Ohio Department of Transportation...Ohio Department of Transportation Central Office • 1980 West Broad Street • Columbus, OH 43223 John Kasich, Governor • Jerry Wray, Director

Ohio Department of Transportation

Central Office • 1980 West Broad Street • Columbus, OH 43223

John Kasich, Governor • Jerry Wray, Director

An Equal Opportunity Employer

Date: April 21, 2017

To: All Current Holders of the Location and Design Manual, Volume 2

Re: Location and Design Manual, Volume Two Revisions

Transmitted herewith are revisions to the Location and Design Manual, Volume 2.

The following revisions have been made:

• Revisions / Additions in Red

• 1008.9 – Updated guidance for Arch or Flat Slab Top Culvert Foundations

The online revisions of the Location and Design Manual, Volume 2 can be found at

http://www.dot.state.oh.us/Divisions/Engineering/Hydraulics/Pages/default.aspx in PDF format.

Technical questions or recommended changes should be directed to Jeff Syar (614) 275-1373 or Matt

Cozzoli (614) 466-3152.

Respectfully,

Jeff Syar, P.E.

Office Administrator, Office of Hydraulic Engineering

NoticeTo ensure proper receipt of future revisions to the manual, please visit the online Design Reference Resource at: http://www.dot.state.oh.us/drrc/Pages/default.aspx

This manual is produced by the Office of Hydraulic Engineering.

Technical questions, recommended changes, or suggestions should be sent to:

Ohio Department of TransportationAttn: Jeffrey Syar, P.E.Administrator, Office of Hydraulic Engineering 1980 West Broad StreetColumbus, Ohio 43223(614) 275-1373

LOCATIONAND

DESIGNMANUAL

VOLUME TWODRAINAGE DESIGN

The OHIO DEPARTMENT of TRANSPORTATION

Table of Contents(Revised April 2017)

Preface........................................................................................................................................................... iOhio Counties............................................................................................................................................... iiiGlossary of Terms........................................................................................................................................ ivDesign Reference Documents ..................................................................................................................... ix1000 Drainage Design Criteria 1001 Hydraulic Design Criteria................................................................................................................10-1

1001.1 Responsibilities...............................................................................................................10-11001.2 Natural Streams..............................................................................................................10-11001.3 Feasibility Study Activities ..............................................................................................10-1

1002 Pipe Criteria....................................................................................................................................10-11002.1 Introduction.....................................................................................................................10-11002.2 General Requirements ...................................................................................................10-21002.3 Conduit Types ................................................................................................................10-3

1003 Hydrology .......................................................................................................................................10-61003.1 Estimation of Magnitude and Frequency of Floods on Ohio Streams ............................10-6

1004 Flood Clearance .............................................................................................................................10-71004.1 General...........................................................................................................................10-71004.2 Design Year Frequency..................................................................................................10-7

1005 Highway Encroachments on Flood Plains ......................................................................................10-71005.1 General...........................................................................................................................10-71005.2 Type of Studies.............................................................................................................10-10

1006 Allowable Headwater....................................................................................................................10-101006.1 Design Storm................................................................................................................10-101006.2 Culvert Headwater Controls .........................................................................................10-101006.3 Bridge Headwater Control ............................................................................................10-111006.4 Controls Specific to Flood Insurance Studies (FIS)......................................................10-12

1007 Pipe Removal Criteria...................................................................................................................10-121007.1 General.........................................................................................................................10-121007.2 Asbestos pipe ...............................................................................................................10-12

1008 Conduit Design Criteria ................................................................................................................10-131008.1 Corrugated and Spiral Rib Steel and Aluminum Pipes, and Corrugated Steel and Aluminum Pipe Arches .............................................................................................................10-131008.2 Rigid Pipe .....................................................................................................................10-141008.3 Thermoplastic Pipe.......................................................................................................10-141008.4 Corrugated Steel and Aluminum Box Culverts and Corrugated Steel Long Span Culverts...................................................................................................................................................10-141008.5 Precast Reinforced Concrete Box Culverts ..................................................................10-141008.6 Precast Reinforced Concrete Three-Sided Flat-Topped Culverts ................................10-151008.7 Precast Reinforced Concrete Arch Sections ................................................................10-151008.8 Precast Reinforced Concrete Round Sections .............................................................10-161008.9 Arch or Flat Slab Top Culvert Foundations ..................................................................10-171008.10 Bridge Foundations ....................................................................................................10-171008.11 Waterproofing Membrane...........................................................................................10-181008.12 Precast Reinforced Concrete Flat Slab Tops, Catch Basin Tops, and Inlet Tops ......10-181008.13 Wingwall Design .........................................................................................................10-18

1009 Subsurface Pavement Drainage...................................................................................................10-181009.1 General.........................................................................................................................10-18

1010 Maintenance of Traffic Drainage ..................................................................................................10-181010.1 General.........................................................................................................................10-18

1011 Temporary Structures...................................................................................................................10-19

1100 Drainage Design Procedures1101 Estimating Design Discharge .........................................................................................................11-1

1101.1 General...........................................................................................................................11-11101.2 Procedures .....................................................................................................................11-1

1102 Open Water Carriers ......................................................................................................................11-41102.1 General...........................................................................................................................11-41102.2 Types of Carriers ............................................................................................................11-41102.3 Ditch Design Criteria - Design Traffic Exceeding 2000 ADT ..........................................11-61102.4 Ditch Design Criteria - Design Traffic of 2000 ADT or Less ...........................................11-91102.5 Design Aids for Ditch Flow Analysis .............................................................................11-10

1103 Pavement Drainage......................................................................................................................11-101103.1 General.........................................................................................................................11-101103.2 Design Frequency ........................................................................................................11-111103.3 Estimating Design Discharge .......................................................................................11-111103.4 Capacity of Pavement Gutters......................................................................................11-121103.5 Pavement Flow Charts .................................................................................................11-121103.6 Bypass Charts for Continuous Pavement Grades........................................................11-121103.7 Grate Catch Basins and Curb Opening Inlets in Pavement Sags ................................11-131103.8 Bridge Deck Drainage ..................................................................................................11-131103.9 Slotted Drains and Trench Drains ................................................................................11-15

1104 Storm Sewers ...............................................................................................................................11-151104.1 General.........................................................................................................................11-151104.2 Design Considerations .................................................................................................11-161104.3 Layout Procedure .........................................................................................................11-171104.4 Storm Sewer Design Criteria ........................................................................................11-181104.5 Hydraulic Design Procedure.........................................................................................11-191104.6 Combined Sanitary Sewer Separation .........................................................................11-19

1105 Roadway Culverts ........................................................................................................................11-201105.1 General.........................................................................................................................11-201105.2 Stream Protection.........................................................................................................11-201105.3 Types of Culvert Flow...................................................................................................11-241105.4 Design Procedure.........................................................................................................11-241105.5 Use of Nomographs......................................................................................................11-251105.6 Design Criteria..............................................................................................................11-251105.7 Special Considerations.................................................................................................11-27

1106 End Treatments ............................................................................................................................11-281106.1 General.........................................................................................................................11-281106.2 Headwall Types ............................................................................................................11-291106.3 Concrete Apron ............................................................................................................11-29

1107 Rock Channel Protection (RCP)...................................................................................................11-301107.1 General.........................................................................................................................11-301107.2 Culvert RCP Types.......................................................................................................11-301107.3 Bridge RCP...................................................................................................................11-30

1108 Agricultural Drainage ....................................................................................................................11-301108.1 Farm Drain Crossings...................................................................................................11-301108.2 Farm Drain Outlets .......................................................................................................11-31

1109 Longitudinal Sewer Location ........................................................................................................11-311109.1 Under Pavement...........................................................................................................11-311109.2 Under Paved Shoulder .................................................................................................11-311109.3 Approval .......................................................................................................................11-31

1110 Reinforced Concrete Radius Pipe and Box Sections ...................................................................11-311110.1 General.........................................................................................................................11-31

1111 Sanitary Sewers ...........................................................................................................................11-321111.1 General.........................................................................................................................11-321111.2 Manholes ......................................................................................................................11-32

1112 Notice of Intent (NOI)....................................................................................................................11-321112.1 General.........................................................................................................................11-321112.2 Routine Maintenance Project .......................................................................................11-33

1112.3 Watershed Specific NOI Requirements........................................................................11-341113 Erosion Control at Bridge Ends ....................................................................................................11-34

1113.1 General.........................................................................................................................11-341113.2 Corner Cone .................................................................................................................11-35

1114 Temporary Sediment and Erosion Control ...................................................................................11-351114.1 General.........................................................................................................................11-351114.2 Cost Estimate for Temporary Sediment and Erosion Control.......................................11-35

1115 Post Construction Storm Water Structural Best Management Practices......................................11-351115.1 General.........................................................................................................................11-351115.2 Project Thresholds for Post-Construction BMP............................................................11-361115.3 Water Quality and Water Quantity Treatment ..............................................................11-361115.4 Water Quality Volume...................................................................................................11-371115.5 Water Quality Flow .......................................................................................................11-381115.6 Project Type - Redevelopment and New Construction.................................................11-38

1116 BMP Selection and Submittals .....................................................................................................11-401116.1 BMP Selection ..............................................................................................................11-401116.2 BMP Submittals ............................................................................................................11-40

1117 BMP Toolbox ................................................................................................................................11-411117.1 Manufactured Systems.................................................................................................11-411117.2 Vegetation Based BMP ................................................................................................11-421117.3 Extended Detention ......................................................................................................11-451117.4 Retention Basin ............................................................................................................11-491117.5 Bioretention Cell ...........................................................................................................11-501117.6 Infiltration ......................................................................................................................11-521117.7 Constructed Wetlands ..................................................................................................11-551117.8 Stream Grade Control ..................................................................................................11-56

1118 Bridge Hydraulics .........................................................................................................................11-561118.1 General.........................................................................................................................11-561118.2 Hydrology and Hydraulics (H&H) Report......................................................................11-56

APPENDIX A – Reproducible FormsAPPENDIX B – Sample Plan NotesAPPENDIX C – Drainage Design Aids

Appendix C has been removed from the printed manual. Drainage Aids can be found at the OHE webpage.

Preface

April 2017 i

Purpose

This Drainage Design Manual has been prepared as a guide for the hydraulic design of highway drainage facilities. Drainage is one of the essential components of roadway design.

Drainage criteria and design outlined in this manual reflects the maximum standard achievable that is based on new project development for traditional design, bid, and build projects. Existing conditions represent the minimum standard, which should always be evaluated against the cost of achieving the maximum standard and the purpose and need of the project. The goal is to make an improvement commensurate with the purpose and need of the project at minimized project costs without negative impacts to safety. Coordinate any proposed deviations from the maximum standard with the Department prior to incorporation into the design. Drainage facilities for most roadway projects account for approximately 25% of the total construction cost of the project. This cost justifies a careful and scientific hydraulic analysis.

Application

Design drainage facilities following the recommended design procedures noted in this manual to minimize the following:

Damage of private property due to flooding Inconvenience to the motorist during moderate to heavy rainfall Disturbance to the environment

Numerous charts have been prepared and are included in the Drainage Design Aids Section of this manual to assist the Drainage Design Engineer with the hydraulic analysis. Other design charts are available in Hydraulic Engineering Circulars and Hydraulic Design Series prepared by the Federal Highway Administration. Reference is made to those charts as required.

This manual is neither a textbook nor a substitute for engineering knowledge, experience, or judgment. It is intended to provide uniform procedures for implementing drainage design decisions and assure quality and continuity in drainage of highways in Ohio. Although the manual is considered a primary source of reference by personnel involved in drainage design in Ohio, it must be recognized that the practices suggested may be inappropriate for some projects because of fiscal limitations or other justifiable reasons.

Consideration must also be given to justifiable hydraulic design standards adopted by city, county, or other local governments when designing facilities under their jurisdiction.

Preparation

The Drainage Design Manual has been developed by the Office of Hydraulic Engineering (OHE). Errors or omissions should be reported to the Administrator, Office of Hydraulic Engineering, Ohio Department of Transportation, 1980 W. Broad Street, Columbus, Ohio 43223.

Format and Revisions

Updating the manual is intended to be a continuous process. Revisions will be issued periodically by OHE and will be available on the Design Reference Resource Center (DRRC) webpage: http://www.dot.state.oh.us/drrc/Pages/default.aspx.

All revisions are shown in red text, and each page has the latest date shown in the bottom corner.

District 11885 N. McCullough St.Lima, OH 45801-0040

419-222-9055fax: 419-222-0438

District 2317 East Poe Rd.

Bowling Green, OH 43402-1330419-353-8131

fax: 419-353-1468

District 3906 Clark Ave.

Ashland, OH 44805-1989800-276-4188 or 419-281-0513

fax: 419-281-0874

District 42088 S. Arlington Rd.

Akron, OH 44306330-786-3100

fax: 330-786-2232

Central O�ce1980 W. Broad Street Columbus, OH 43223

614-466-7170fax: 614-644-8662

ODOT Web Site: www.transportation.ohio.gov

District 9650 Eastern Ave. PO Box 467

Chillicothe, OH 45601888-819-8501 or 740-773-2691

fax: 740-775-4889

District 10338 Muskingum Dr. PO Box 658

Marietta, OH 45750800-845-0226 or 740-568-3900

fax: 740-373-7317

District 112201 Reiser Ave.

New Philadelphia, OH 44663330-339-6633

fax: 330-308-3942

District 125500 Transportation Blvd.

Gar�eld Heights, OH 44125-5396800-732-4896 or 216-581-2100

fax: 216-584-2274

District 59600 Jacksontown Rd.

Jacksontown, OH 43030740-323-4400

fax: 740-323-3715

District 6400 East William St.

Delaware, OH 43015740-833-8000

fax: 740-833-8100

District 71001 St. Marys Ave.

Sidney, OH 45365-0969888-200-9919 or 937-492-1141

fax: 937-497-9734

District 8505 S. State Route 741

Lebanon, OH 45036-9518800-831-2142 or 513-932-3030

fax: 513-932-7651

2

1

7

8 9 10

6

3

5 11

4

12

Ohio Department of TransportationDistricts

Ohio Department of Transportation Districts

Richland

Scioto

Delaware

Pickaway

Washington

Noble

Guernsey

As

hla

nd

Tusc

araw

as

Hamilton

Clinton

Montgom

ery

Marion

Morrow

Auglaize

Miami

Shelby

Hancock

Hardin

Wyandot

Lake

Cuyahoga

Ottawa

Erie

Huron

Lorain

Geauga

Portage

Ashtabula

Trumbull

Medina

Wayne Stark

Sandusky

Seneca

Wood

Lucas

Williams

Defiance

Paulding

Henry

Fulton

Mahoning

Putnam

Van Wert Crawford Allen

Mercer

Darke

Logan

Union

Champaign

Clark

Preble

Butler

Warren

Greene

Madison

Fayette

Knox

Holmes

Columbiana

Carroll

Harrison Jeff

erso

n

Coshocton

Licking

Muskingum Belmont

Monroe

Morgan

Athens

Perry Fairfield

Hocking

Vinton

Meigs

Gallia

Jackson

Ross

Cle

rmo

nt

Brown Adams

Highland

Pike

Lawrence

Su

mm

it Bowling Green

Lima

Sidney

Lebanon

Delaware

Jacksontown

Chillicothe Marietta

Ashland

Gar�eld Hts.

Akron

New Phil.

Franklin

Columbus

Ohio Counties

April 2017 iii

County Code DistrictAdams ADA 9Allen ALL 1Ashland ASD 3Ashtabula ATB 4Athens ATH 10Auglaize AUG 7

Belmont BEL 11Brown BRO 9Butler BUT 8

Carroll CAR 11Champaign CHP 7Clark CLA 7Clermont CLE 8Clinton CLI 8Columbiana COL 11Coshocton COS 5Crawford CRA 3Cuyahoga CUY 12

Darke DAR 7Defiance DEF 1Delaware DEL 6

Erie ERI 3

Fairfield FAI 5Fayette FAY 6Franklin FRA 6Fulton FUL 2

Gallia GAL 10Geauga GEA 12Greene GRE 8Guernsey GUE 5

Hamilton HAM 8Hancock HAN 1Hardin HAR 1Harrison HAS 11Henry HEN 2Highland HIG 9Hocking HOC 10Holmes HOL 11Huron HUR 3

Jackson JAC 9Jefferson JEF 11

Knox KNO 5

Lake LAK 12Lawrence LAW 9

County Code DistrictLicking LIC 5Logan LOG 7Lorain LOR 3Lucas LUC 2

Madison MAD 6Mahoning MAH 4Marion MAR 6Medina MED 3Meigs MEG 10Mercer MER 7Miami MIA 7Monroe MOE 10Montgomery MOT 7Morgan MRG 10Morrow MRW 6Muskingum MUS 5

Noble NOB 10

Ottawa OTT 2

Paulding PAU 1Perry PER 5Pickaway PIC 6Pike PIK 9Portage POR 4Preble PRE 8Putnam PUT\ 1

Richland RIC 3Ross ROS 9

Sandusky SAN 2Scioto SCI 9Seneca SEN 2Shelby SHE 7Stark STA 4Summit SUM 4

Trumbull TRU 4Tuscarawas TUS 11

Union UNI 6

Van Wert VAN 1Vinton VIN 10

Warren WAR 8Washington WAS 10Wayne WAY 3Williams WIL 2Wood WOO 2Wyandot WAY 1

Glossary of Terms

iv April 2017

Aggregate Drain – A trench filled with granular material extending laterally from the pavement base or subbase layer to an outlet on the roadway foreslope with the intent of draining surface and/or ground water away from the pavement base and/or subbase.

Anti-seep Collar – Device that prevents the flow of water through the surrounding soil around a conduit that is used as an outlet for an infiltration, retention, or detention basin.

Apron – Paving at a pipe inlet or outlet, or upstream of a catch basin, constructed along the channel bottom to prevent scour.

Backwater Analysis – The determination of water surface profiles measured at specific locations upstream from a constriction causing an increased flow depth upstream.

Bankfull Discharge – The flow or stage of a stream corresponding to the highest level of active deposition. It is the discharge that, on the average, fills a main channel to the point of overflowing. For simplicity, it is generally considered to be approximately the 2 year discharge.

Bridge – Structure that has a span greater than or equal to 10 feet as measured in a parallel direction to the roadway centerline.

Camber – A slight convex curve constructed into the bottom of a pipe to overcome anticipated settlement problems.

Cast-in-place Structure – A concrete drainage structure which is placed in forms and cured at its final location. Precast beams on cast-in-place foundations are considered cast-in-place structures.

Catch Basin – A structure for intercepting flow from a gutter or ditch and discharging the water through a conduit.

Coefficient of Runoff (C) – A value, varying with the ground and ground cover, which is used in the Rational formula to determine the amount of a rainfall which is directed to streams and not absorbed into the ground.

Conduit – A closed structure such as a pipe that has a span less than 10 feet as measured in a parallel direction to the roadway centerline.

Corner Bearing Pressure – The pressure generated at the corners of pipe arch structures.

Culvert – A structure which is typically designed hydraulically to take advantage of submergence at the inlet to increase hydraulic capacity. A structure used to convey surface runoff through embankments. A structure, as distinguished from a bridge, which is usually covered with embankment and is composed of structural material around the entire perimeter, although some are supported on spread footings with the stream bed serving as the bottom of the culvert.

Cutoff Wall – A wall that extends downward from the end of a structure to below the expected scour depth, or to a scour-resistant material.

Design Discharge (Q) – The peak rate of flow for which a drainage facility is designed. Usually given in cubic feet per second (cfs).

Design Service Life – The average usable life of a pipe or structure. Certain drainage situations require a 50-year life, more stringent situations require a 75-year design life.

Design Storm – A given rainfall amount, areal distribution, and a time distribution, used to estimate runoff. The rainfall amount is either a given frequency (25-year, 50-year, etc.) or a specific large value.

Detention Basin – A structure that holds water for a short period of time before releasing it to the natural water course.

April 2017 v

Diversion Dike – An embankment to control or to deflect water away from a soil bank.

Drainage Area – The area contributing discharge to a stream at a given point.

Drop-down Entrance (Drop inlet) – A type of inlet which conveys the water from a higher elevation to a lower elevation smoothly without a free fall at the inlet.

Elliptical Pipe – Pipe which is manufactured with a span greater than rise to be utilized in shallow cover situations.

Ephemeral Stream – A stream or reach of stream that does not flow for parts of the year. As used here, the term includes intermittent streams with flow less than perennial. It is located above the water table year-round. Ground water is not a source of water supply.

Feasible – Term used to define BMP practicability. BMP shall be: technically feasible, implemented within the procured highway right-of-way, safe for the traveling public and ODOT maintenance personnel, cost effective as compared to the benefit, and will be legal at the State, Federal, and Local levels. FEMA – Federal Emergency Management Agency.

Flood Fringe – The portion of the floodplain outside of the floodway.

Flood Hazard Evaluation – The act of determining if flood levels within a watercourse for a 100-year flood, or other recurrence interval floods have a significantly increased detrimental impact on upstream property.

Flood Insurance Rate Map (FIRM) – The official map of a community on which FEMA has delineated both the special hazard areas and the risk premium zones applicable to the community.

Flood Insurance Study – A book with information regarding flooding in a community that is developed in conjunction with the FIRM. It discusses the engineering methods used to develop the FIRMs.

Flood Plain Culverts – Relief culverts that are placed in addition to a bankfull culvert at a higher elevation across the flood plain to allow multiple outlets for floodwaters.

Flood Plain Study – A more extensive analysis of the effects of flood levels on upstream property than the Flood Hazard Evaluation. This analysis is to be used when upstream properties appear to have been subjected to a significantly increased detrimental effect from the flood flows.

Floodway – The portion of the floodplain which is effective in carrying flow, within which this carrying capacity must be preserved and where the flood hazard is generally highest.

Flowline – see Thalweg

Forebay – Depressed area that offers pretreatment of sediment laden storm water prior to a retention, detention, or infiltration basin.

Friction Slope – The slope of the energy grade line.

Granular Material – A term relating to the uniform size of grains or crystals in rock, larger than sand or pea gravel.

Grate – A type of screen made from sets of bars used to allow the interception of flow, and also to cover an area for pedestrian or vehicular traffic.

Headwall – The structural appurtenance placed at the open end of a pipe to control an adjacent highway embankment and protect the pipe end from undercutting.

April 2017vi

Headwater – That depth of water impounded upstream of a culvert due to the influence of the culvert constriction, friction, and configuration.

Highest Known Water Elevation – The highest known flood water in record.

Hydraulic Grade Line – A line coinciding with the level of flowing water in an open channel. In a closed conduit operating under pressure, a line representing the distance water would rise in a pitot tube at any point along a pipe. The hydraulic grade line is equal to the pressure head (P/γ) along the pipe.

Hydraulic Gradient – The slope of the hydraulic grade line for a storm sewer or culvert.

Idealized Channel Geometry – Physical, geometric, and hydraulic characteristics of a channel determined from empirical relationships.

Impervious Surface – Hardened pavement surface.

Infiltration Rate – The rate at which water penetrates the surface of the soil at any given instant. The rate can be limited by the infiltration capacity of the soil or the rate at which water is applied.

Inlet – A structure for capturing concentrated surface flow. May be located along the roadway, in a gutter, in the highway median, or in the field.

Inlet Control – The situation where the culvert hydraulic performance is controlled by the entrance geometry only.

Intermittent Stream – A stream that is dry for part of the year, ordinarily more than 3 months.

Manhole – A structure by which one may access a closed drainage system.

MS4 Phase II Regulated Area – Area that has been designated by the Ohio EPA that requires a storm water management plan to discharge storm water.

Multiple Cell Culvert – A culvert with more than one barrel.

New Development Project – Projects that change the land use of a site from undeveloped to developed characteristics.

Normal Water Elevation – The water elevation in a stream which has not been affected by a recent heavy rain runoff. The water level which could be found in the stream most of the year. This elevation will be lower than the ordinary high water.

Ordinary High Water – The line on the shore established by the fluctuation of water and indicated by physical characteristics such as: a clear natural line impressed on the bank, shelving, changes in the character of soil, destruction of terrestrial vegetation, or other appropriate means that consider the characteristics of the surrounding areas. This elevation is lower than the highest known water.

Outlet Control – The situation where the culvert hydraulic performance is determined by the controlling water surface elevation at the outlet, the slope, length and roughness of the culvert barrel, as well as the entrance geometry.

Overland Flow – Water which travels over a surface and reaches a stream.

Perennial Stream – A stream that flows continuously for all or most of the year. The water table is located above the stream bed for most of the year.

Permeability – The quality of the soil that enables water to move downward through the soil profile. It is measured in units of inches per hour.

April 2017 vii

pH – The reciprocal of the negative logarithm of the Hydrogen ion concentration. Neutral water has a pH value of 7. A measure of the acidity of a substance, if less than 7; alkalinity if greater than 7.

Pipe Arch – Pipe which is manufactured with a span greater than rise (semicircular crown, small-radius corners, and large radius invert) to be utilized in shallow cover situations.

Pipe Underdrain – A longitudinal subsurface drainage system composed of a perforated pipe at the bottom of a narrow trench filled with permeable material and lined with a geotextile in erodible soils, with the intent of draining surface and/or ground waters away from the pavement base and/or subbase.

Porosity – The volume of voids divided by the total volume and multiplied by 100.

Prefabricated Edge Drain – A longitudinal underdrain system utilizing a narrow trench and a vertically elongated, perforated water carrier with the intent of draining surface and/or ground water away from the pavement base and/or subbase.

Prefabricated Structure – Any drainage structure which is manufactured off site and transported to the location of intended use. It may be of various materials, including concrete, clay, metal, thermoplastics, etc. It may be of various shapes including circular, elliptical, rectangular, arched, etc.

Premium Joints – Watertight joints.

Pretreatment – Preliminary filtering of sediment laden storm water prior to secondary treatment through a structural best management practice.

Rainfall Intensity (i) – The amount of rainfall occurring in a unit of time, normally given in inches per hour.

Reference Reach – A length of channel with stable geometric, physical, and hydraulic characteristics. A representation of the desired outcome of a restored channel.

Retention Basin – A structure that holds water on a permanent basis.

Roughness Coefficient (n) – The measure of texture on the surface of channels and conduits. Usually represented by the “n-value” coefficient used in Manning’s open channel flow equation.

Runoff – That part of the precipitation which runs off the surface of a drainage area after all abstractions are accounted for.

Sanitary Sewer – A conduit or pipe system which carries household and/or industrial wastes. Sanitary sewers do not convey storm water.

Sediment Basin – A basin or tank in which stormwater containing settleable solids is retained, to remove by gravity or filtration a part of the suspended matter.

Sediment Dam – A dam that is designed to allow suspended sediment to settle out of flowing water in a controlled area.

Short-circuiting – The act of storm water bypassing the intended route.

Soil Bioengineering – The use of live and dead plant materials, in combination with natural and synthetic support materials, for slope stabilization, erosion reduction, and vegetative establishment.

Spring Line – The locus of the horizontal extremities of a transverse section of a conduit.

Step Backwater or Standard Step Method – An iterative use of the energy equation for determining the water surface profile of an open channel.

April 2017viii

Storm Sewer – A conduit or pipe drainage system that conveys storm water, subsurface water, condensate, or similar discharge, but not household or industrial wastes.

Thalweg – The lowest bed elevation in a natural channel cross section. Also used in reference to the profile line extending down a channel along the lowest bed elevation.

Tailwater – The depth of flow in the stream directly downstream of a drainage facility, measured from the invert at the culvert outlet. Often calculated for the discharge flowing in the natural stream without the highway constriction. Term is usually used in culvert design and is the depth measured from the downstream flow line of the culvert to the water surface.

Time of Concentration (tc) – Time required for water to flow from the most distant point on a drainage area to the measurement or collection point.

TMDL (total maximum daily load) Regulated Stream – An Impaired water body as defined by the Ohio EPA that can still meet water quality standards if the daily maximum pollutant load is regulated.

Two Stage Channel – A channel that contains a cross sectional area for low and high discharges. Water of The United States – Water bodies subject to Army Corps of Engineers jurisdiction through Section 404 of the Clean Water Act. They include all interstate waters such as lakes, rivers, streams (including intermittent streams) and wetlands. Ephemeral streams are included if they have a clearly defined channel.

Design Reference Documents

April 2017 ix

Highway Hydrology (FHWA Hydraulic Design Series No. 2)

Design Charts for Open Channel Flow (FHWA Hydraulic Design Series No. 3)

Hydraulic Design of Highway Culverts (FHWA Hydraulic Design Series No. 5)

River Engineering For Highway Encroachments (FHWA Hydraulic Series No. 6)

Design of Stable Channels with Flexible Linings (Federal Highway Engineering Circular No. 15)

Evaluating Scour at Bridges (FHWA Hydraulic Engineering Circular No. 18)

Stream Stability at Highway Structures (FHWA Hydraulic Engineering Circular No. 20)

Urban Drainage Design Manual Second Edition (FHWA Hydraulic Engineering Circular No. 22)

Bridge Scour and Stream Instability Countermeasures Experience, Selection, and Design Guidance (FHWA Hydraulic Engineering Circular No. 23)

Estimation of Peak-Frequency Relations, Flood Hydrographs, and Volume - Duration - Frequency Relations of Ungaged Small Urban Streams in Ohio (USGS Open-File Report 93-135)

Estimation of Flood Volumes and Simulation of Flood Hydrographs for Ungaged Small Rural Streams in Ohio (USGS Water Resources Investigations Report 93-4080)

Culvert Durability Study (ODOT/L&D/82-1)

Internal Energy Dissipators for Culverts (FHWA/OH-84/007)

Standard Construction Drawings (ODOT)

Construction and Material Specifications Handbook (ODOT)

Rainwater and Land Development, Ohio’s Standards for Stormwater Management Land Development and Urban Stream Protection (Third Edition, 2006).

Stream Corridor Restoration: Principles, Practices and Processes (United States Department of Agriculture), October 1998 Additional design resources can be found at the FHWA website at:http://www.fhwa.dot.gov/engineering/hydraulics/

Bankfull Characteristics of Ohio Streams and Their Relation to Peak Streamflows (Scientific Investigations Report 2005-5153)

A Streamflow Statistics (StreamStats) Web Application for Ohio (Scientific Investigations Report 2006-5312

FHWA Ultra Urban BMP webpage. https://www.environment.fhwa.dot.gov/ecosystems/ultraurb/index.asp

USEPA National Pollutant Discharge webpage http://water.epa.gov/polwaste/npdes/swbmp/

Urban Runoff Quality Management, WEF Manual of Practice No. 23, 1998, published jointly by the WEF and ASCE.

Ohio Environmental Protection Agency http://www.epa.state.oh.us

Table of Contents(Revised April 2017)

1000 Drainage Design Criteria1001 Hydraulic Design Criteria................................................................................................................10-1

1001.1 Responsibilities...............................................................................................................10-11001.2 Natural Streams..............................................................................................................10-11001.3 Feasibility Study Activities ..............................................................................................10-1

1002 Pipe Criteria....................................................................................................................................10-11002.1 Introduction.....................................................................................................................10-1

1002.1.1 Deviation by ODOT Districts...........................................................................10-11002.1.2 Deviation by Local ..........................................................................................10-1

1002.2 General Requirements ...................................................................................................10-21002.2.1 Pipe Materials.................................................................................................10-21002.2.2 Outlet Velocity Control ....................................................................................10-21002.2.3 Special Shapes...............................................................................................10-21002.2.4 Structure File Number/Culvert File Number ...................................................10-2

1002.3 Conduit Types ................................................................................................................10-31002.3.1 Type A Conduits .............................................................................................10-31002.3.2 Type B Conduits .............................................................................................10-31002.3.3 Type C Conduits.............................................................................................10-41002.3.4 Type D Conduits.............................................................................................10-41002.3.5 Type E Conduits .............................................................................................10-41002.3.6 Type F Conduits .............................................................................................10-41002.3.7 Culvert Rehabilitation .....................................................................................10-5

1003 Hydrology .......................................................................................................................................10-61003.1 Estimation of Magnitude and Frequency of Floods on Ohio Streams ............................10-6

1003.1.1 General ...........................................................................................................10-61003.1.2 Alternate Discharge Sources for Bridges .......................................................10-61003.1.3 Limitations ......................................................................................................10-6

1004 Flood Clearance .............................................................................................................................10-71004.1 General...........................................................................................................................10-71004.2 Design Year Frequency..................................................................................................10-7

1005 Highway Encroachments on Flood Plains ......................................................................................10-71005.1 General...........................................................................................................................10-7

1005.1.1 Flood Data and Flood Insurance Studies (FIS) ..............................................10-81005.1.2 Proposed Construction in FEMA Zones .........................................................10-81005.1.3 Exceptions ......................................................................................................10-91005.1.4 ODOT Self-Permit Process ............................................................................10-9

1005.2 Type of Studies.............................................................................................................10-101005.2.1 Hazard Evaluation for Watercourses without a Defined FEMA SFHA .........10-101005.2.2 Detailed Study ..............................................................................................10-10

1006 Allowable Headwater....................................................................................................................10-101006.1 Design Storm................................................................................................................10-101006.2 Culvert Headwater Controls .........................................................................................10-10

1006.2.1 Design Storm Controls .................................................................................10-101006.2.2 Check Storm Controls ..................................................................................10-111006.2.3 Limitations ....................................................................................................10-111006.2.4 Controls Specific to Flood Plain Insurance Studies......................................10-11

1006.3 Bridge Headwater Control ............................................................................................10-111006.4 Controls Specific to Flood Insurance Studies (FIS)......................................................10-12

1007 Pipe Removal Criteria...................................................................................................................10-121007.1 General.........................................................................................................................10-121007.2 Asbestos pipe ...............................................................................................................10-12

1008 Conduit Design Criteria ................................................................................................................10-131008.1 Corrugated and Spiral Rib Steel and Aluminum Pipes, and Corrugated Steel and Aluminum Pipe Arches .............................................................................................................10-13

1008.1.1 Material Durability.........................................................................................10-13

1008.1.2 Designation and Thickness ..........................................................................10-131008.1.3 Cambered Flow Line ....................................................................................10-131008.1.4 Height of Cover.............................................................................................10-131008.1.5 Foundation Reports ......................................................................................10-13

1008.2 Rigid Pipe .....................................................................................................................10-141008.2.1 General .........................................................................................................10-141008.2.2 Height of Cover.............................................................................................10-14

1008.3 Thermoplastic Pipe.......................................................................................................10-141008.3.1 Height of Cover.............................................................................................10-14

1008.4 Corrugated Steel and Aluminum Box Culverts and Corrugated Steel Long Span Culverts...................................................................................................................................................10-14

1008.4.1 Designation and Thickness ..........................................................................10-141008.4.2 Height of Cover.............................................................................................10-141008.4.3 Foundation Reports ......................................................................................10-14

1008.5 Precast Reinforced Concrete Box Culverts ..................................................................10-141008.5.1 Designation...................................................................................................10-141008.5.2 Height of Cover.............................................................................................10-15

1008.6 Precast Reinforced Concrete Three-Sided Flat-Topped Culverts ................................10-151008.6.1 Designation...................................................................................................10-151008.6.2 Height of Cover.............................................................................................10-151008.6.3 Foundation Reports ......................................................................................10-15

1008.7 Precast Reinforced Concrete Arch Sections ................................................................10-151008.7.1 Designation...................................................................................................10-151008.7.2 Height of Cover.............................................................................................10-161008.7.3 Foundation Reports ......................................................................................10-16

1008.8 Precast Reinforced Concrete Round Sections .............................................................10-161008.8.1 Designation...................................................................................................10-161008.8.2 Height of Cover.............................................................................................10-161008.8.3 Foundation Reports ......................................................................................10-17

1008.9 Arch or Flat Slab Top Culvert Foundations ..................................................................10-171008.10 Bridge Foundations ....................................................................................................10-171008.11 Waterproofing Membrane...........................................................................................10-181008.12 Precast Reinforced Concrete Flat Slab Tops, Catch Basin Tops, and Inlet Tops ......10-181008.13 Wingwall Design .........................................................................................................10-18

1009 Subsurface Pavement Drainage...................................................................................................10-181009.1 General.........................................................................................................................10-18

1010 Maintenance of Traffic Drainage ..................................................................................................10-181010.1 General.........................................................................................................................10-18

1011 Temporary Structures...................................................................................................................10-19

1000 Drainage Design Criteria

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1001 Hydraulic Design Criteria

1001.1 Responsibilities

The Office of Hydraulic Engineering (OHE) is responsible for the hydraulic design standards for all surface drainage systems and bridge structures owned and maintained by the Department. Further responsibility includes: conduit durability, culvert inspection and inventory, post construction storm water best management practices, and the Department’s Municipal Separate Storm Sewer System (MS4) program.

1001.2 Natural Streams

Channel designs and channel relocations of all natural streams passing through a proposed highway facility will be the responsibility of the owner. All other channel designs and channel relocations of natural streams are the responsibility of OHE.

1001.3 Feasibility Study Activities

Encroachments on floodplains for transportation projects are governed in part by the Code of Federal Regulations (CFR), Part 650, Subpart A. The Project Development Process (PDP) and hydraulic design criteria function to satisfy the requirements of this regulation.

1002 Pipe Criteria

1002.1 Introduction

The Departments Pipe Criteria governs the determination of the size and type of pipe specified or permitted for the various items of highway drainage financed totally or in part with state or federal funds.

Deviations from this Pipe Criteria concerning type of pipe or pipe placement must be based on sound engineering judgment and/or life cycle cost analysis. Deviations involving the specification of only one type of pipe material where special conditions prevail must include sound engineering judgment such as:

Excessive cover for a rigid pipe. Where a larger corrugated pipe would require a higher pavement grade to satisfy minimum cover

requirements or require more cells than a rigid alternate. Where a metal pipe arch would be required as an alternate to a round rigid pipe. The outfall velocity would require an energy dissipater. Site conditions prevented the existing conduit material to meet design service life. Verification that

the existing conduit material had been correctly designed to ODOT durability design needs to be documented.

If a structure type study is performed and the cost analysis indicates a lower cost.

The use of a single material type is subject to the approval of OHE. 1002.1.1 Deviation by ODOT Districts

ODOT Districts may submit a written request for deviation from this Pipe Criteria. Include documentation that justifies the deviation and the completed Drainage Criteria form (see Appendix A). Submit the documentation to the Administrator of OHE.

1002.1.2 Deviation by Local

Proposed deviations from this Pipe Standard and/or construction specifications by local political subdivisions or agencies will be considered for all portions of the project that are maintained by the political subdivision or agency.

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ODOT Districts may permit a deviation from this Pipe Standard provided the local political subdivision or agency agrees to fund any additional costs inferred due to the conduit material selection. The deviation requires alternate bid items, per Section 1307.2.7 of L&D Volume 3, to determine the additional costs. The alternatives include ODOT’s Pipe Standard/construction methods and the local’s material selection/construction methods. Add additional notes or details as required by the local.

1002.2 General Requirements

1002.2.1 Pipe Materials

The type of pipe materials listed under the various conduit types in Section 611.02 of the Construction and Material Specifications are considered equal within their size, structural and material durability limitations.

1002.2.2 Outlet Velocity Control

When permissible pipe alternates have different velocity characteristics, the design specified for erosion control will satisfy the most severe velocity condition of the permissible alternates. In this case, “erosion control” refers to controls placed in the stream channel at the outlet end of the pipe such as rock channel protection, and does not refer to energy dissipaters.

Where the calculated culvert outlet velocity exceeds 20 feet per second or 15 feet per second in areas of poor soil such as fine sand or sandy silt, roughness elements (protruding concrete rings inside the pipe) may be specified at the outlet end of the alternates to reduce the velocity below the maximum allowable.

The design of internal energy dissipator ring chambers is provided in report FHWA/OH-84/007 “Internal Energy Dissipators for Culverts”. This report and ring chamber details can be obtained from OHE.

Where the outlet velocity for a corrugated pipe is less than 20 feet per second while the outlet velocity for a smooth pipe requires a ring chamber, the corrugated pipe may be specified exclusively.

1002.2.3 Special Shapes

Special shaped conduits (elliptical concrete, corrugated metal arch or pipe arch, or prefabricated box or three-sided structures) are generally limited for use under shallow cover installations or extremely low or restrictive headwater control otherwise requiring multiple circular conduits to satisfy allowable headwater conditions. Generally elliptical concrete and corrugated metal pipe arch of the required size to satisfy hydraulic conditions are to be shown on the plan.

Special shaped conduits may be provided to conform to the cross-sectional geometry of sensitive streams identified in the environmental documentation.

Where corrugated metal and structural plate pipe arches are specified or permitted, a foundation investigation shall be submitted as required by Section 1008.1.5.

1002.2.4 Structure File Number/Culvert File Number

Structures having an opening measured along the centerline of roadways of 10’ or greater require a Structure File Number (SFN). Multiple openings where the extreme ends of the openings are 10’ or greater also require a SFN, where the clear distance between opening is less than half of the smaller contiguous opening.

Structures having an opening measured along the centerline of roadway of less than 10’ require a Culvert File Number (CFN). A new CFN is generated by the Culvert Collector application.

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1002.3 Conduit Types

1002.3.1 Type A Conduits

Type A conduits shall be designated for soil-tight, sealed-joint, open-ended cross drains under pavements and paved shoulders. The minimum size culvert (or cross drain) to be specified shall be based on the roadway type and depth of fill from the flowline to roadway surface.The minimum required round (or equivalent deformed) pipe sizes are listed in Figure 1002-1. For culverts under freeways or high fills (16 feet), the size shall be increased one pipe size over the required size to allow for future repair. Ensure the pipe is only upsized once.

All hydraulically adequate pipe alternates which provide the required service life shall be shown on the plans and listed in the pertinent pay item. In the applicable size ranges, alternates should include, vitrified clay, concrete, plastic, corrugated steel, and corrugated aluminum. For corrugated metal pipe, the corrugation profile which requires the thinnest metal shall be listed. Where durability requires increased thicknesses of the corrugated steel alternate, the 1-inch corrugation profile should be specified for pipe diameters over 48 inches. For the steel corrugation profile specified, all combinations of thickness and protection providing the required service life shall be specified.

If the alternates listed in the plan are different sizes, show the pipe length associated with the smallest pipe size.

When extending existing Type A conduits, ensure the extensions match the existing material in kind.

Furnish all Type A conduits under State and Federal routes with a minimum service life of 50 years. Use a service life of 75 years at sites that have one of the following characteristics:

1. Fill Height ≥ 16 feet (measured from flowline to finished grade)

2. Freeways

3. Structures defined as a Bridge

The pH of the normal stream flow and the presence of abrasive flow conditions are factors that determine the material durability and service life. Measure the pH of the normal stream flow in the field using a calibrated pH meter capable of measuring to a tenth. Determine if the streambed material is abrasive by observation. Presence of sand, pea gravel, or sharp cobbles where a stream gradient or flow is sufficient to cause movement of the material would be an indicator that the site is abrasive. Otherwise, the site should be considered non-abrasive. Field measurement of pH is required. Use Figures 1002-2 and 1002-3 if flow is not present in the conduit.

Use Figures 1002-4, 5 and 6 to determine the pipe materials for the design service life. These tabulations are based on the ODOT Culvert Durability Study and later reports. Ensure the pH and abrasiveness determination is included in the plans in accordance to L&D, Volume 3.

If it is known that future flow conditions will be more corrosive than existing conditions, specify protection that is greater than what is currently required. Submit documentation of the known future flow condition and the proposed additional protection. 1002.3.2 Type B Conduits

Type B conduits shall be designated for soil-tight, sealed joint sewers under pavements, paved shoulders, and commercial or industrial drives. In areas with highly erodible soils (e.g., fine sands or silts), premium joints shall be provided.

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Additional protection (epoxy coating as per 706.03 for concrete pipe and polymer coating per 707.04 for asphalt paved corrugated steel pipe) shall be provided for storm sewers carrying corrosive flow.

Conduit placed through MSE walls or in the fill of MSE walls are limited to 706.02 with joints per 706.11.

The design service life for all Type B conduit is 75 years. No additional design considerations are required to achieve the design service life.

1002.3.3 Type C Conduits

Type C conduits shall be designated for soil-tight, sealed joint sewers not under pavements, paved shoulders, or commercial or industrial drives.In areas with highly erodible soils (e.g., fine sands or silts), premium joints shall be provided.

Additional protection (epoxy coating as per 706.03 for concrete pipe and polymer coating per 707.04 for asphalt paved corrugated steel pipe) shall be provided for storm sewers carrying corrosive flow.

The design service life for all Type C conduit is 75 years. No additional design considerations are required to achieve the design service life.

1002.3.4 Type D Conduits

Type D conduits shall be designated for pipes under driveways and bikeways. The minimum size required is 12 inches. For sizes 24 inches and larger, it will be necessary to submit calculations and specify pipe sizing required to satisfy the hydraulic controls. Such analyses shall be submitted with the Drainage Review plans. The design frequency used to analyze the hydraulic performance of the Type D conduit is the same as that used for the flow capacity of the connected ditch or channel and the headwater for that frequency shall not exceed a point 1 foot below the edge of the pavement. If potential exists for the drive pipe headwater to encroach on the adjacent roadway, the drive pipe shall be sized utilizing a design frequency as per 1004.2. Generally, the pipe alternates listed in 611.02 of the Construction and Material Specifications are applicable, except that equal size corrugated pipe will provide satisfactory alternates for sizes smaller than 24 inches. If the control is critical, a hydraulic analysis will be required to determine the proper size of pipe alternates.

Drive pipes under commercial or industrial drives shall be designed for material durability as per 1002.3.1. Additional protection for residential and field drives may be specified if conditions warrant.

1002.3.5 Type E Conduits

Type E conduits shall be designated for farm drain headers inside or outside of the right-of-way lines. Headers are ordinarily provided to intercept small, closely spaced lines in a tiled field thereby precluding the need for numerous field tile outlets through the backslope of the highway ditch.

1002.3.6 Type F Conduits

Type F conduits shall be designated where a butt joint or a short length jointed pipe would be undesirable as noted below:

A. For the steep portion of a median outlet under an embankment slope 4:1 or steeper, including any necessary pipe bends.

B. For the outlets of underdrains or farm drains through the slope or connecting to a drainage structure. When used for underdrain outlets, the following pay item description shall be used: Item 611 " Conduit, Type F for Underdrain Outlets. Provide 10 feet of conduit at each outlet into a drainage structure.

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C. For farm drains larger than 12 inches that outlet through slopes flatter than 4:1, provide a 20 foot length of Type F Conduit with an animal guard at the outlet.

D. For pipe underdrains that span the trench of a lower conduit, unless the crossing is more than 12 inches above the granular backfill of the lower conduit, provide a minimum length of 10 feet of Type F Conduit.

Type F conduits may be used beyond the paved shoulder to eliminate a ditch in front of a yard where such ditch elimination can be justified. When required by hydraulic analysis, all proper sized alternates shall be specified.

1002.3.7 Culvert Rehabilitation

A range of material applications and solutions are available for culvert rehabilitation. These solutions are used to extend the service life of existing conduits by adding durability or in some cases structural strength. The following specifications or methods are available:

CMS 611.11 – Field Paving of Existing Pipe

Supplemental Specification 833 – Conduit Renewal Using Spray Applied Structural Liner

Supplemental Specification 834 – Conduit Renewal Using Resin Based Liner

Supplemental Specification 837 – Liner Pipe (various material)

Supplemental Specification 841 – Conduit Renewal Using Spiral Wound Liner

Plan Note – Cured In Place Pipe (CIPP)

Field paving of existing conduits has been a solution to add durability to conduits for many years. This solution is a cost effective way to add many years of service life to an existing conduit provided the culvert has good structural shape and is structurally sound (i.e.: not moving). This solution should always be evaluated first.

Supplemental Specification 833 – Conduit Renewal Using Spray Applied Structural Liner is a solution that provides structural rehabilitation to existing conduits via a spray application. The interior of the conduit is spray lined with a factory blended cementitious geopolymer or resin based material.

Supplemental Specification 834 – Conduit Renewal Using Resin Based Liner is a solution that adds durability by placing a resin based material on the interior of the existing conduit via a spray application. This solution will add service life to an existing conduit. Supplemental Specification 837- Liner Pipe offers a solution that lines an existing conduit with another conduit. This specification requires the slip-lined conduit to be grouted in-place and in some cases would be considered a structural solution if the slip-lining material is designed accordingly. Supplemental Specification 938 is an additional material option utilized by Supplemental Specification 837.

Ensure all available Liner Pipe materials in Supplemental Specification 837 are shown in the plans if they satisfy the hydraulic conditions. Ensure the hydraulic calculations are evaluated for the alternative slip-line materials. Submit all Liner Pipe projects to OHE for review and approval if one material alternative is specified in the plans. Furnish a cost analysis verifying the use of a single material option.

Supplemental Specification 841 – Conduit Renewal Using Spiral Wound Liner is a unique solution that may be used to line various shaped conduits such as: Round, Elliptical, Box, or Pipe Arch. This solution custom manufactures the conduit on site from polyvinyl chloride material with either a special machine or by manual labor. The manufactured conduit is placed into the existing conduit and the void is filled with grout. This solution adds durability to the existing host conduit. Use of this solution requires approval from OHE. The

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culvert rehabilitation method shall be designed to match existing headwater conditions. Appropriate erosion control measures shall be designed for increased outlet velocities.

If the proposed design does not meet the existing headwater conditions or the outside diameter constraint described above, contact OHE for approval.

Plan Note – Cured in Place Pipe (CIPP) offers a structural rehabilitation solution that lines an existing conduit with a form fitting liner. The resin saturated liner is inserted into the conduit. Once in place the liner is expanded and cured to mold itself to the host conduit. Ensure adequate hydraulic capacity is maintained. While CIPP can be used for culvert rehabilitation other techniques in this section should be explored first. CIPP is best suited for closed systems such as storm sewers.Additional information and guidance for culvert rehabilitation can be found at: http://www.dot.state.oh.us/Divisions/Engineering/Hydraulics/Pages/default.aspx

1003 Hydrology

1003.1 Estimation of Magnitude and Frequency of Floods on Ohio Streams

1003.1.1 General

USGS Water Resources Investigations Report 89-4126 “Techniques for Estimating Flood-Peak Discharges of Rural Unregulated Stream in Ohio” was developed cooperatively by the United States Geological Survey and the State of Ohio. This bulletin is an update of Bulletin 32 (1959), Bulletin 43 (1969), and Bulletin 45 (1977). This report provides the latest hydrologic information for determining the magnitude and frequency of floods for rural streams in Ohio. USGS Report 06-5312 “StreamStats” is a USGS web based application for estimating stream flow statistics and basin characteristics on unregulated streams. Use StreamStats or the techniques presented in Report 03-4164 to determine the design peak discharge for hydraulic structures designated by or for ODOT. When applying this technique, the tributary with the largest contributing drainage area, not the longest reach, should be considered. USGS Water Resources Investigation Report 93-4080 “Estimation of Flood Volumes and Simulation of Flood Hydrographs for Ungaged Small Rural Streams in Ohio” shall be used to determine flood volumes and hydrographs for rural areas within the limits prescribed in the report.

1003.1.2 Alternate Discharge Sources for Bridges

Discharge estimates may be calculated by other methods for comparisons against verified flood elevations and other known river data to ensure that the most realistic discharge for the area is used for the design of the waterway opening. Submit calculations and comparisons to the Office of Hydraulic Engineering for review.

Flood Insurance Studies (FIS); U.S. Corps of Engineer Flood Studies; U.S. Soils Conservation Studies; U.S. Water Resources Data and other reliable sources may be used as reference information in estimating discharges and flood elevations. However, for waterway crossings located in a FIS area, the base discharge (Q100) from the FIS takes precedence over all other calculated discharges.

Where a U.S. Geological Survey estimate is in conflict with that of another agency, contact the agency in order to resolve the discrepancy. In general, the U.S. Geological Survey estimate is given preference.Design proposed structures upstream or downstream from a flood control facility for discharges as supplied by the U.S. Corps of Engineers, Ohio Department of Natural Resources or the agency responsible for the flood control facility.

1003.1.3 Limitations

Specific limitations on the use of the USGS regression equations can be found in each report. The USGS Report 89-4126 and USGS 2006-5312 were developed for flood-peak discharge estimates for unregulated streams draining rural basins.

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USGS Open File Report 2432 "Estimation of Peak-Frequency Relations, Flood Hydrographs, and Volume - Duration - Frequency Relations of Ungauged Small Urban Streams in Ohio” may be used in the design of culverts, detention basins, large storm sewers, and large open channels with urban drainage areas within the limits prescribed in the report.

Use the rational method (Section 1101.2.2) in the design of pavement inlets, roadway ditches, culverts, and small storm sewers. Use this method for drainage areas up to a maximum of 200 acres where no well defined natural channel exists and sheet flow prevails.

For additional guidance on the proper use of USGS regression equations see Transportation Research Record 1319 Report “Information Needs for the Proper Application of Hydrologic Regional Regression Equations”.

1004 Flood Clearance

1004.1 General

Where a new highway crosses or is located in a flood plain, the highway grade shall normally be set such that the low edge of the pavement will clear the design water surface profile for existing conditions by 3 feet, and bridges (low chord) will generally clear the water surface profile of the design year frequency flood. These clearances may be reduced where an economic comparison of alternatives shows that a reduction in clearance will result in significant savings, giving full consideration to future flood-related costs relative to: highway operation, maintenance, and repair; highway-aggravated flood damage to other property; and for additional or interrupted highway travel.

Flood clearances may also be reduced to protect important ecological resources as identified in the environmental documentation. An economic comparison of alternatives shall be performed to determine the future flood-related costs relative to: highway operation, maintenance, and repair; highway-aggravated flood damage to other property; and for additional or interrupted highway travel. 1004.2 Design Year Frequency

Freeways or other multi-lane facilities with limited access.…..….. 50 YearOther Highways (2000 ADT and over) and Freeway Ramps……..25 YearOther Highways (under 2000 ADT)………………………….…....... 10 Year*Bicycle pathway………………………………………………..……… 5 Year

* Unless otherwise approved by OHE.

1005 Highway Encroachments on Flood Plains

1005.1 General

All highways that encroach on floodplains, bodies of water or streams, shall be designed to permit conveyance of the 100-year flood without causing significant damage to the highway, the watercourse, body of water or other property.

Hydraulically design structures and/or channels to convey the design-year discharge. Ensure the structure and/or channel will convey the 100-year discharge without causing property damage. Inundation of the highway is acceptable for the 100-year discharge, but it is not permitted for the design-year discharge. Water surface elevations caused by existing structures do not have to be lowered to meet the 100-year discharge.

Longitudinal highway encroachments require alternative location studies to be summarized in the Feasibility Study (L&D Section 1403.3).

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1005.1.1 Flood Data and Flood Insurance Studies (FIS)

Flood hazard areas are delineated on Flood Insurance Rate Maps (FIRM) and Flood Insurance Studies (FIS) as Special Flood Hazard Areas (SFHA). SFHAs are defined as the areas that will be inundated by a flood having a 1-percent chance of occurring in any given year (also known as the 100-year flood). The water surface elevation of the 1-percent annual chance flood is referred to as the Base Flood Elevation (BFE). The SFHA is typically comprised of two components, the floodway and fringe.

The floodway is the channel of a watercourse and the adjacent land areas that must be reserved in order to discharge the 1-percent annual chance flood (or base flood) without cumulatively increasing the water surface elevation more than a designated height. The flood fringe is the portion of the floodplain, outside of the floodway, that contains slow-moving or standing water (see figure 1006.1).

The limits of the floodway are created by a computer model (HEC-RAS) that conveys the base flood discharge within artificial encroachments placed within the floodplain until an allowable water surface surcharge is established. The allowable surcharge for the National Flood Insurance Program (NFIP) is set at one (1) foot, however local authorities may reduce the allowable surcharge below the one foot criteria.

Special consideration must be given when designing a structure located within a reach of channel that is part of an FIS. Perform a step backwater analysis of the floodplain to the extent required by FEMA.

SFHAs are labeled as different Zones. Flood Insurance Zone designations may be accessed at the following web site: https://msc.fema.gov/portal

The more common FIS Risk zones are as follows:

ZONE DESCRIPTION

AAreas subject to inundation by the 1-percent-annual-chance flood. Detailed hydraulic analyses have not been performed, no BFE or flood depth is shown. Use hydrology methods outlined in 1003.Areas subject to inundation by the 1-percent-annual-chance flood determined by detailed study methods. BFEs are shown within these zones. (Zone AE is used on new and revised maps in place of Zones A1-A30). An existing hydraulic model should be available from FEMA. Use the 100 year discharge found in the FEMA model for the analysis.

AE, A1-A30 AE (BFEs WITH Floodway): BFEs and floodways have been determined and depicted on the FIRM.AE (BFEs WITHOUT Floodway): BFEs have been determined, but no floodway has been generated (and is not delineated on the FIRM). In SFHAs with BFEs, but no floodway, a hydrologic and hydraulic (H&H) analysis is required demonstrating that the cumulative effect of proposed development, when combined with all other existing and anticipated development will not increase the water surface elevation of the base flood by more than the allowable surcharge.

1005.1.2 Proposed Construction in FEMA Zones

Construction within FEMA Zone A requires documentation through the ODOT self-permit process and coordination with the Local Floodplain Coordinator. A BFE has not been established. Limit the allowable water surface surcharge to the requirements from the Local Floodplain Coordinator or one (1) foot, whichever is less. Contact OHE if the allowable surcharge required by the Local Floodplain Coordinator is not feasible. Construction within FEMA Zones AE or A1-A30 requires documentation through the ODOT self-permit process, coordination with FEMA, ODNR, and the Local Floodplain Coordinator. Where a floodway is established, ensure the proposed construction spans the floodway if feasible. A No-Rise condition is preferred if construction is performed within the floodway. If proposed construction within the floodway

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creates any increase in the water surface elevation above the BFE, a variance is required and approval through the appropriate FEMA map revision processes will be necessary. Where no floodway is established and the proposed construction creates any increase in the water surface elevation above the BFE + Allowable Surcharge, a variance is required and approval through the appropriate FEMA map revision processes will be necessary.

The Ohio Department of Natural Resources Floodplain Management Program (FMP) coordinates the National Flood Insurance Program (NFIP) throughout the State of Ohio as specified in Section 1521 of the Ohio Revised Code. The FMP works as a liaison between communities that participate in the NFIP and the Federal Emergency Management Agency (FEMA), who administers the program nationally. Additional information can be found at: http://water.ohiodnr.gov/water-use-planning/floodplain-management

Locally administered projects are required to obtain a permit from the Local Floodplain Coordinator for proposed work within a FEMA SFHA. A current list of Floodplain Coordinators can be found at:http://soilandwater.ohiodnr.gov/portals/soilwater/pdf/floodplain/Floodplain%20Manager%20Community%20Contact%20List_10_14.pdf

1005.1.3 Exceptions

ODOT has determined that the following types of projects will have no impact upon the BFE and a hydraulic analysis is not required:

a. Bridge Paintingb. Bridge maintenance (i.e.: bridge deck or superstructure replacement) that is performed where the

existing low chord of the bridge has freeboard over the BFE including the allowable surcharge.c. Any bridge or culvert maintenance that does not change the alignment, grade, or hydraulic capacity

of the existing structure as determined by the District Hydraulic Engineer

1005.1.4 ODOT Self-Permit Process

Compliance with federal, state and local floodplain standards is required; however, obtaining a permit from the Local Floodplain Coordinator is not required for work administered by or for the Department (ORC 1521.13 D). The Department will self-permit under this process. In order to maintain and verify compliance, thorough documentation is necessary.

The Local floodplain coordinator must be contacted early in the process to obtain any local standards that may be more restrictive than FEMA requirements (i.e.: allowable surcharge, compensatory storage, etc.). Ensure all documentation requesting Local requirements is kept in the project file.

For construction within the following FEMA Zones, provide a copy of the following documentation to the Local Floodplain Coordinator and the project file.

Zone A:a. Letter of Notification (Form LD-52)b. Letter of Compliance (Form LD-51), note if a variance requesting relief from local standards is

required.c. Calculations demonstrating the carrying capacity of the stream is maintained.d. If a variance is requested for relief from local standards, further coordination is required between

ODOT, the Local Floodplain Coordinator, ODNR and FEMA. Contact OHE if a variance is required.

Zone AE, without Floodway:a. Letter of Notification (Form LD-52)b. Letter of Compliance (Form LD-51), note if a variance requesting relief from local standards is

required.c. Hydrologic and Hydraulic calculations.

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10-10 April 2017

d. If a variance is requested for relief from local standards, further coordination is required between ODOT, the Local Floodplain Coordinator, ODNR and FEMA. Contact OHE if a variance is required.

Zone AE, with Floodway:a. Letter of Notification (Form LD-52)b. Letter of Compliance (Form LD-51), note if a variance requesting relief from local standards is

required.c. Hydrologic and Hydraulic calculations.d. No-Rise Certification (Form LD-50), if applicable.e. If a variance is requested for relief from local standards, further coordination is required between

ODOT, the Local Floodplain Coordinator, ODNR and FEMA. Contact OHE if a variance is required.

1005.2 Type of Studies

1005.2.1 Hazard Evaluation for Watercourses without a Defined FEMA SFHA

A flood hazard evaluation is required for all watercourse involvements except for FEMA Zone A, AE, or A1-A30 zones or where roadway culverts are provided to satisfy minimum size requirements. . A Flood Hazard Evaluation is a condition statement regarding the nature of the upstream area, the extent of upstream flooding, and whether buildings are in the 100 year frequency flood plain. Perform the following for a flood hazard evaluation:

A. Determine the water surface elevation of the design year and 100-year flood.

B. Delineate the inundation area for the peak water surface elevation for the design year and 100-year flood on a topographic map or a digital map.

C. Evaluate the impacts of any increase in the flooding limits.

1005.2.2 Detailed Study

If the Hazard Evaluation indicates a significant increase in the flooding of upstream property, a Detailed Study is required. Furnish a Detailed Study in highly urbanized areas where the potential for flooding cannot be accurately assessed without an analysis of the entire floodplain. For pre-fabricated structures, the Detailed Study, including a step-backwater analysis, will be authorized after review of the Hazard Evaluation, by OHE.

1006 Allowable Headwater

1006.1 Design Storm

The frequency of the design storm shall be as stated in Section 1004.2.

1006.2 Culvert Headwater Controls

1006.2.1 Design Storm Controls

Headwater depth for all culverts (Type A Conduits) shall not exceed any of the following controls for the design storm:

A. 2 feet below the near, low edge of the pavement for drainage areas 1000 acres or greater and 1 foot below for culverts draining less than 1000 acres.

B. 2 feet above the inlet crown of the culvert or above a tailwater elevation that submerges the inlet crown

in flat to rolling terrain.C. 4 feet above the inlet crown of a culvert in a deep ravine.

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April 2017 10-11

D. 1 foot below the near edge of pavement for bicycle pathways.

1006.2.2 Check Storm Controls

Headwater depth for all culverts (Type A Conduits) shall not exceed any of the following controls for the applicable check frequency storm.

A. 2 feet below the lowest ground elevation adjacent to an occupied building for a 50-year storm (it is not intended, however, to lower existing high water elevations around buildings).

B. The designer should generally limit the maximum 100-year headwater depth to twice the diameter or rise of the culvert.

C. A replacement structure should be sized to prevent overtopping by the 100-year flood where such overtopping would not occur with the existing structure.

D. A replacement structure should be sized such that flooding of upstream productive land is not increased for the 100-year flood when compared to the existing structure. Judgment shall be used in implementing this criteria, considering the type of upstream property and sensitivity to the accuracy of the computed flood stages.

E. No increase in 100-year headwater elevation shall occur in a FEMA designated floodway.

1006.2.3 Limitations

1006.2.1 B and C; and 1006.2.2 B, are arbitrary headwater controls. When 1006.2.1 B is applicable, use smooth pipe to establish the allowable headwater in feet. When 1006.2.1 C controls, use corrugated pipe to establish the headwater and thereby permit the same headwater elevation regardless of type of pipe. More heading will be considered if pipe sizes can be reduced and not cause flooding damage upstream or excessive outlet velocity.

1006.2.1 B and C are arbitrary controls and generally apply to small culverts. Where large structures (greater than or equal to 10 feet in span) are involved, the structure should be sized to pass the design storm while maintaining a free water surface through the structure, unless tail water controls.

The near low edge of pavement is the location where roadway overtopping will occur. This may or may not be located directly over the culvert. Where the overtopping point on the roadway is outside the watershed break, the ditch break overflow elevation should be utilized as a headwater control in lieu of 1006.2.1 A.

1006.2.4 Controls Specific to Flood Plain Insurance Studies

When making an encroachment on a NFIP designated floodplain in the floodway fringe, the rise in the water surface above the natural 100 year flood elevation is limited by the community. Contact the community to determine the allowable rise.

No increase in the 100 year water surface is allowed when encroaching on a NFIP designated floodway.

1006.3 Bridge Headwater Control

Evaluate the headwater generated by a bridge in accordance to a flood hazard evaluation. Ensure the headwater meets the following:

A. Match the existing headwater for a bridge replacement for the design storm and the check flood to the maximum extent practicable. Any increase in headwaters verify the upstream impacts.

B. Design flood does not contact the low chord for new structures on new alignment.

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C. Regulations from Conservancy Districts if they are more restrictive than the Departments.

D. Controls specific to a FIS.

1006.4 Controls Specific to Flood Insurance Studies (FIS)

Contact the Local Floodplain Coordinator early in the design process to determine the allowable headwater increase and or the permitting requirements. A current list of Floodplain Coordinators may be found at: http://soilandwater.ohiodnr.gov/portals/soilwater/pdf/floodplain/Floodplain%20Manager%20Community%20Contact%20List_10_14.pdf

When making an encroachment on a FIS designated floodplain in the floodway fringe, the rise in the water surface above the natural 100 year flood elevation is limited by the community. See Figure 1006-1 for a graphical definition of the floodway, floodway fringe, and flood plain.

No increase in the 100 year water surface is allowed when encroaching on a FIS designated floodway.

1007 Pipe Removal Criteria

1007.1 General

Use the following guidelines to determine whether an existing pipe, regardless of type, being taken out of service should be abandoned or removed.

A. Pipes 8 inches in diameter or rise, or less, regardless of depth or height of fill, may be abandoned in place.

B. Pipes 10 inches through 24 inches in diameter or rise with less than 3 feet of final cover should be removed or filled; with more than 3 feet of final cover they may be abandoned in place. (The designer should use discretion in removing small pipes based on roadway importance, pipe material longevity and if the pipe is under existing rigid pavement or base which is to remain in place.)

C. Pipes over 24 inches in diameter or rise should generally be removed. (The designer should use discretion in removing any pipe with more than 10 feet of cover.)

1007.2 Asbestos pipe

Asbestos pipe is a regulated material. Designers should make reasonable efforts to identify existing asbestos pipes in the plans and, when necessary, provide appropriate removal quantities.

In the past, pipe containing asbestos was allowed on ODOT, LPA and utility projects under the following specifications:

ASTM C663 Asbestos-Cement Storm Drain Pipe AASHTO M217 AWWA C400 AWWA C603 ASTM C296 Asbestos-Cement Pressure Pipe ODOT CMS 707.09 Asbestos Bonded Bituminous Corrugated Steel Pipe and Pipe Arches

(Circa 1983) ODOT CMS 706.15 Asbestos Cement Perforated Underdrain Pipe (Circa. 1973)

Transite is a common brand name for a type of asbestos pipe. Asbestos can also be found in insulation wrapped around water pipes.

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Reasonable efforts to identify asbestos pipes would include the following:

A. Examination of original construction plans and specifications.

B. Contact with the owner of the pipe (e.g., utility company or LPA).

C. Inspection of the pipe for markings when the pipe is exposed during routine maintenance operations.

Removal of asbestos pipe is specified in the most current CMS as Item 202 Asbestos Pipe Removed. For projects to be constructed under the 1997 CMS, use Item 202 Pipe Removed, As Per Plan and indicate that the pipe must be removed by a certified asbestos contractor.

Asbestos is a hazard only when it becomes airborne. Pipes that are otherwise unaffected by ODOT work do not need to be removed simply because they contain asbestos.

Not all asbestos pipes will be identified by a records search. Construction inspectors are being advised to test suspicious pipe for asbestos. If asbestos pipe is identified, the contractor will be compensated by change order.

1008 Conduit Design Criteria

1008.1 Corrugated and Spiral Rib Steel and Aluminum Pipes, and Corrugated Steel and Aluminum Pipe Arches

1008.1.1 Material Durability

The Criteria outlined in Section 1002 specifying types of protective coatings and/or extra metal thickness shall be followed.

1008.1.2 Designation and Thickness

The corrugation profile and required metal thickness for structural strength is furnished by the Manufacturer in accordance to Construction and Material Specifications Handbook (CMS) Item 611.

1008.1.3 Cambered Flow Line

Where soil conditions at the site indicate that appreciable settlement is expected, provide a cambered flow line. Show the cambered flow line as a vertical curve following the Manufacturer recommendation.

1008.1.4 Height of Cover

See General Notes for Figures 1008-1 through 1008-6 and 1008-15 through 1008-19 for minimum height of cover.

1008.1.5 Foundation Reports

Conduct an investigation of the supporting foundation material to estimate the bearing capacity of the material and determine that no settlement will occur. A foundation investigation is required for all proposed metal pipe installations with 100 feet of fill or more and all pipe arch installations. Submit the foundation report with the Stage 1 review.

Refer to section 1008.9 for information on foundation types.

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1008.2 Rigid Pipe

1008.2.1 General

Where soil conditions at the site indicate that appreciable settlement is expected, provide a cambered flow line. Show the cambered flow line as a vertical curve following the Manufacturer recommendation.

1008.2.2 Height of Cover

The maximum allowable height of cover is measured from the top of the pipe to the pavement surface. The minimum cover, from the top of the pipe to the top of the subgrade, or finish grade for pipe not under pavements, is 9 inches; however, in no installation shall the distance from the top of the pipe to the pavement surface be less than 15 inches.

1008.3 Thermoplastic Pipe

1008.3.1 Height of Cover

The maximum allowable height of cover is measured from the top of the conduit to the pavement surface or to finished grade for pipes not under pavement. The minimum cover, from the top of the pipe to the top of the subgrade, is 12 inches; however, in no installation shall the distance from the top of the pipe to the pavement surface, or finish grade for pipes not under pavement, be less than 18 inches.

1008.4 Corrugated Steel and Aluminum Box Culverts and Corrugated Steel Long Span Culverts.

1008.4.1 Designation and Thickness

The corrugation profile and metal thickness required shall be in accordance with the AASHTO LRFD Bridge Design Specifications design methodologies. Structural strength design is furnished by the Manufacturer in accordance to Construction and Material Specifications Handbook (CMS) Item 611.

The skew of the structure relative to the roadway shall be given in 1° increments and typically should not exceed 15°.

1008.4.2 Height of Cover

In no case shall the minimum cover, measured from the trough of the corrugation profile to the pavement surface, be less than 18 inches. In addition to the above requirements, corrugated steel and aluminum box culverts shall be provided with adequate cover to ensure that the culvert rib stiffeners are located completely within the subgrade.

1008.4.3 Foundation Reports

Conduct an investigation of the supporting foundation material and estimate the bearing capacity of the foundation material. Submit the foundation report for all proposed metal box and long span culvert installations with the Stage 1 review.

1008.5 Precast Reinforced Concrete Box Culverts

1008.5.1 Designation

The allowable sizes of precast reinforced concrete box culverts shall be as given in Figure 1008-14. The pay item description shall include the height of cover (design earth cover), rounded to the highest 1 foot.

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Structures with a span of 12 feet or less shall be designed as per ASTM C 1577.

Structures with spans 14 feet or greater require a special design. CMS Item 706.05 refers to SS 940 which lists the special designs for each span and fill height (design cover).

1008.5.2 Height of Cover

The maximum allowable height of cover is measured from the top of the culvert to the pavement surface. The maximum height of cover will be limited to 10 feet. Greater covers may be provided contingent upon the approval of the Manufacturer. A special design is required.

1008.6 Precast Reinforced Concrete Three-Sided Flat-Topped Culverts

1008.6.1 Designation

Precast reinforced concrete three-sided, flat-topped culverts shall have a minimum clear span of 14 feet and minimum opening rise of 4 feet; and a maximum clear span of 34 feet and maximum opening rise of 10 feet. The individual culvert units may be skewed in 5° increments with a maximum skew of 30°. Designate the skew of the structure relative to the roadway in 1° increments with a maximum skew of 30°.

The minimum deck thickness for the culvert units is 12 inches and the minimum leg thickness for the culvert units is 10 inches. The design should be based on these dimensions.

1008.6.2 Height of Cover

The maximum allowable height of cover is measured from the top of the culvert to the pavement surface. The maximum height of cover should be limited to 5 feet. Greater covers may be provided contingent upon the approval of the Manufacturer.

1008.6.3 Foundation Reports

Conduct an investigation of the supporting foundation material and estimate the bearing capacity of the foundation material. Submit the foundation report for all proposed flat-topped, three-sided culvert installations with the Stage 1 review.

Show the footing and/or pedestal wall vertical and horizontal unfactored reaction forces in the plans.

Refer to section 1008.9 for information on foundation types.

1008.7 Precast Reinforced Concrete Arch Sections

1008.7.1 Designation

Precast reinforced concrete arch sections have a clear span of 12 to 34, 36, 42, 48, 54, 60 feet and an opening rise of 4 feet through 13 feet (maximum). Use of other sizes requires that a Proprietary Waiver Request (Proprietary Product Approval Request) be completed and signed by the contracting agency. This form may be found at the following web site:http://www.dot.state.oh.us/Divisions/Planning/LocalPrograms/Forms/Forms/AllItems.aspx

Designate the skew of the structure relative to the roadway in 1° increments with a maximum skew of 30°. Individual culvert sections may only be skewed with written permission from OSE.

Obtain the deck thickness and leg thickness for the culvert units from the manufacturer. Show the maximum and minimum cover on the plans. Design the footing keyway based on the leg thickness plus 6 inches. Design the guardrail post length based on the deck thickness and cover.

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Precast reinforced concrete arch sections may only be used for roadway grade separation structures with written approval from the OSE. Standard design modifications, including but not limited to increased concrete thickness, concrete admixtures, epoxy coating of concrete surfaces and epoxy coating of reinforcing steel may be required for approval for use as roadway grade separation structures.

1008.7.2 Height of Cover

The maximum allowable height of cover is measured from the top of the culvert to the finished surface. The maximum height of cover is limited to 12 feet. Cover greater than 12 feet may be provided contingent upon the approval of the Manufacturer.

The minimum cover, from the top of the arch sections to the top of the pavement is 12 inches. However, in no case shall the top of the arch sections be located above the top of subgrade.

1008.7.3 Foundation Reports

Conduct an investigation of the supporting foundation material and estimate the bearing capacity of the foundation material. Submit the foundation report for all precast reinforced concrete arch section culvert installations with the Stage 1 review.

Show the footing and/or pedestal wall vertical and horizontal unfactored reaction forces in the plans.

Refer to section 1008.9 for information on foundation types.

1008.8 Precast Reinforced Concrete Round Sections

1008.8.1 Designation

Precast reinforced concrete round sections are one or two piece structures with a clear span of 12, 16, 20, 24, 30, 36, 42, 48, 54, 60, 66, 72, 78 and 84 feet available in various rises and shapes. Use of other sizes requires that a Proprietary Waiver Request (Proprietary Product Approval Request) be completed and signed by the contracting agency. This form may be found at the following web site:http://www.dot.state.oh.us/Divisions/Planning/LocalPrograms/Forms/Forms/AllItems.aspx

Designate the skew of the structure relative to the roadway in 1° increments with a maximum skew of 30°. Individual culvert sections may only be skewed with written permission from OSE.

Obtain the section thickness for the sections from the manufacturer. Show the maximum and minimum cover on the plans. Design the footing keyway based on the section thickness plus 8 inches. Design the guardrail post length based on the section thickness and cover.

Precast reinforced concrete round sections may only be used for roadway grade separation structures with written approval from OHE. Standard design modifications, including but not limited to increased concrete thickness, concrete admixtures, epoxy coating of concrete surfaces and epoxy coating of reinforcing steel may be required for approval for use as roadway grade separation structures.

1008.8.2 Height of Cover

The maximum allowable height of cover is measured from the top of the round sections to the finished surface. The maximum height of cover is limited to 12 feet. Cover greater than 12 feet may be provided contingent upon the approval of the Manufacturer.

The minimum cover, from the top of the round sections to the top of the pavement is 12 inches. However, in no case should the top of the arch sections be located above the top of subgrade.

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April 2017 10-17

1008.8.3 Foundation Reports

Conduct an investigation of the supporting foundation material and estimate the bearing capacity of the foundation material. Submit the foundation report for all precast reinforced concrete round section installations with the Stage 1 review. Include with the foundation report a letter from the manufacturer stating the reactions for foundation design.

Show the footing and/or pedestal wall vertical and horizontal unfactored reaction forces in the plans.

Refer to section 1008.9 for information on foundation types.

1008.9 Arch or Flat Slab Top Culvert Foundations

Arch or flat slab topped culverts are supported on either spread footings or deep foundations such as piles or drilled shafts. When a series of precast, three-sided structures are used to produce a multiple span structure over a waterway, spread footings are not permitted.

Provide deep foundations according to the Bridge Design Manual (BDM). Refer to the Office of Geotechnical Engineering (OGE) for the design of foundations on spread footings.

Reasonable and prudent hydraulic analysis of a bridge design requires that an assessment be made of the proposed bridge’s vulnerability to undermining due to potential scour. Because of the extreme hazard and economic hardships posed by a rapid bridge collapse, special considerations must be given to selecting appropriate flood magnitudes for use in the analysis.The hydraulics engineer must always be aware of and use the most current scour forecasting technology.

Reference HEC-23, Volume 2, Section 6, Design Guideline 18, to estimate scour depths for three sided structures, for all flow conditions. Use Kr of 0.38, for the riprap sizing equation (18.1). Use Type C Rock Channel Protection as a minimum. Access and/or download the HEC-23 publication from the publications section of the FHWA Hydraulics Library web site: http://www.fhwa.dot.gov/engineering/hydraulics/library_listing.cfm

Provide a cost comparison justification study between alternative structure types, including bridges, when utilizing a deep foundation. Submit the cost comparison justification study during the preliminary engineering phase.

Provide a keyway in the foundation to set the arch or flat slab topped culverts into. The width of the keyway is a minimum of 6 inches wider than the precast leg (3 inches on both sides of the leg). The depth of the keyway is a minimum of 3 inches.

1008.10 Bridge Foundations

Perform a scour evaluation for all bridges not founded on scour resistant bedrock. When evaluating scour for a replacement structure, review all inspection reports for evidence of stream degradation (lowering of stream bed), scour or previous scour countermeasures. Compute scour depths with the equations in HEC-18 (Hydraulic Engineering Circular No. 18, Pub. No. FHWA NHI 01-001), “Evaluating Scour at Bridges”.

Consider scour depth in the design of the substructures and the location of the bottom of footings and minimum tip elevations for piles and drilled shafts.

All major rehabilitation work requires a scour evaluation. The scour evaluation may consist of determining what the bridge is founded on. For example, for a bridge rehabilitation, noting that the bridge is founded on scour resistant bedrock or deep foundations to bedrock, would constitute the scour evaluation. As a minimum, piles shall be embedded 15 ft. below the streambed elevation.

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Provide a narrative of findings and recommended scour counter-measures in the Structure Type Study. Include a statement regarding the susceptibility of the stream banks and flow line to scour, and also the susceptibility of the piers and abutments to scour.

1008.10.1 Scour Design Flood Frequencies Bridge foundations are designed to withstand the effects of scour caused by hydraulic conditions from floods larger than the design flood. The frequencies for the scour design flood and the scour check flood are determined by the hydraulic design flood frequency used to hydraulically size the bridge. Use the following table to determine the flood frequency for scour:

Hydraulic Design Flood Frequency

Scour Design Flood Frequency

Scour Check Flood Frequency

Q10 Q25 Q50Q25 Q50 Q100Q50 Q100 Q500

1008.11 Waterproofing Membrane

Apply an external waterproofing membrane to all precast reinforced concrete box culverts, three-sided flat-topped culverts, arch culverts and round sections. Use Item 512 Waterproofing, Type 2 along the vertical sides and Type 2 or 3 across the top of the structure. Type 3 waterproofing shall be used if pavement is to be used directly on top of the structure. Provide an overlap of a minimum of 12 inches of the top membrane to the vertical membrane.

1008.12 Precast Reinforced Concrete Flat Slab Tops, Catch Basin Tops, and Inlet Tops

Precast Reinforced Concrete Flat Slab Tops, Catch Basin Tops, and Inlet Tops shall be designed in accordance with ASTM C478. When the structure is under pavement and the span is greater than 10 feet, the design loading for the structural design shall be HL-93.

1008.13 Wingwall Design

When not using the standard construction drawings or design data sheets, design wingwalls in accordance to the current AASHTO LRFD Bridge Design Specifications. Assume no passive forces are acting on the toe of the wall.

1009 Subsurface Pavement Drainage

1009.1 General

Subsurface pavement drainage is required on all projects except when located in an area having a granular subgrade. See the Pavement Design Manual, Section 205 Subsurface Pavement Drainage for guidance.

1010 Maintenance of Traffic Drainage

1010.1 General

Positive drainage during Maintenance of Traffic (MOT) operations is furnished under items 614 and 615 of the CMS for most projects. Evaluate MOT drainage for projects on Interstates and Expressways that have one or more of the following or as directed by the District:

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A. Multi-phased MOT operations B. Profile changes in the roadway that temporarily create a sag point different than the final designC. Traffic maintained adjacent to concrete barrier with less than 2 feet clear distance from the edge of lane

to the edge of barrier

Furnish a minimum dry lane width of 10 feet for each travelled lane. Determine the spread of water on the pavement using a 2 year design frequency unless a different frequency is specified by the District.

Provide MOT drainage by utilizing permanent drainage items for final design and temporary drainage items. Temporary drainage items may include items such as inlets, storm sewers, culverts, ditches, perforated conduits, catch basins, conduits jacked and bored, opening cuts in concrete barrier, French drains, pavement saw cut openings, etcetera. These drainage items may conflict with future MOT phases and may require removal quantities in subsequent MOT phases.

Use permanent drainage items for final design where feasible. Furnish a minimum diameter of 12 inches for temporary storm sewer and 18 inches for temporary culverts. Provide temporary drainage items on the MOT plan per plan note D124.

1011 Temporary StructuresThe design year and other hydraulic requirements for temporary structures are defined in CMS 502.02. Ensure scour depth is accounted for in the in the design of a temporary bridge and foundation.

Show the water surface elevation (“high water”) and velocity of the design year discharge on the temporary structure plans. Ensure the design year discharge does not contact the lowest portion of the superstructure of a temporary bridge.

Culvert pipes may be used in lieu of a bridge structure provided controls specified in Section 1006 are not exceeded for the design year discharge.

Refer to Section 500 of the Bridge Design Manual for other details regarding temporary structures.

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1000 Drainage Design Criteria – List of Figures

April 2017

Figure Subject

1002-1 Minimum Culvert Sizes

1002-2 Water pH Contours - Average for Counties

1002-3 Water pH Contours - Values of Individual Culverts

1002-4 Requirements for Concrete Pipe Protection

General Notes for Figures 1002-5 and 1002-6

1002-5(50) Requirements for Corrugated Metal Pipe Thickness and Protection at Non-Abrasive Sites - 50-year Design Service Life

1002-5(75) Requirements for Corrugated Metal Pipe Thickness and Protection at Non-Abrasive Sites - 75-year Design Service Life

1002-6(50) Requirements for Corrugated Metal Pipe Thickness and Protection at Abrasive Sites - 50-year Design Service Life

1002-6(75) Requirements for Corrugated Metal Pipe Thickness and Protection at Abrasive Sites - 75-year Design Service Life

1006-1 Floodway Schematic

General Notes for Figures 1008-1 through 1008-9

1008-1 Minimum Height of Cover - Corrugated Steel Pipe

1008-2 Minimum Height of Cover - Corrugated Steel Pipe Arches

1008-3 Minimum Height of Cover - Structural Plate Corrugated Steel Pipe

1008-4 Minimum Height of Cover - Structural Plate Corrugated Steel Pipe Arches (18-inch Corner Radius)

1008-5 Minimum Height of Cover - Structural Plate Corrugated Steel Pipe-Arches (31-inch Corner Radius)

1008-6 Minimum Height of Cover - Corrugated Steel Spiral Rib Pipe

1008-7 Table Deleted January 2013

1008-8 Table Deleted January 2013

1008-9 Table Deleted January 2013

General Notes for Figures 1008-10 through 1008-14

1008-10 Table Deleted January 2013

1008-11 Reinforced Concrete Circular Pipe

1000 Drainage Design Criteria – List of Figures

April 2017

Figure Subject

1008-12 Reinforced Concrete Elliptical Pipe

1008-13 Table Deleted January 2013

1008-14 Maximum Allowable Height of Cover - Reinforced Concrete Box Culverts

General Notes for Figures 1008-15 through 1008-19

1008-15 Minimum Height of Cover - Corrugated Aluminum Pipe

1008-16 Minimum Height of Cover - Corrugated Aluminum Pipe Arches

1008-17 Minimum Height of Cover - Structural Plate Corrugated Aluminum Pipe

1008-18 Minimum Height of Cover - Structural Plate Corrugated Aluminum Pipe Arches

1008-19 Minimum Height of Cover - Corrugated Aluminum Spiral Rib Pipe

General Notes – Figures 1002-5 and 1002-6

Tables 1002-5(50) & 1002-5(75)

Tables 1002-5(50) and 1002-5(75) are based on equations 6 and 8 from the ODOT Location & Design publication 82-1, “Culvert Durability Study” including:

A 15-year service life for Bituminous Coating with Invert Paving for culverts 54” and larger.

A 25-year service life for Bituminous Coating with Invert Paving for culverts 48” and smaller.

A 35-year service life for Aluminum Coating with pH above 5.0

A 50-year service life for Polymeric Coating

All base metals must provide a minimum of 10 years of service life.

Corrugated aluminum alloy pipe (707.21 and 707.22) and aluminum alloy structural plate pipe (707.23) are acceptable with the minimum thickness required to satisfy cover conditions for all non-abrasive sites with a pH between 5.0 and 9.0

A blank space in the table indicates that a gage, which satisfies the design service life, is not available.

Tables 1002-6(50) & 1002-6(75)

Tables 1002-6(50) and 1002-6(75) are based on equations 7 and 9 from the ODOT Location & Design publication 82-1, “Culvert Durability Study” including:

A 15-year service life for Bituminous Coating with Invert Paving for culverts 54” and larger.

A 25-year service life for Bituminous Coating with Invert Paving for culverts 48” and smaller.

A 35-year service life for Aluminum Coating with pH above 5.0.

A 50-year service life for Polymeric Coating

All base metals must provide a minimum of 10 years of service life.

Corrugated aluminum alloy pipe (707.21 and 707.22) with Concrete Field Paving and aluminum alloy structural plate pipe (707.23) with Concrete Field Paving are acceptable with the minimum thickness required to satisfy cover conditions for all abrasive sites with a pH between 5.0 and 9.0

A blank space in the table indicates that a gage, which satisfies the design service life, is not available.

Abbreviations and Symbols

* Concrete field paving shall be epoxy coated per 706.03 for pH < 5.0

** Externally coated per AASHTO M243

w/CFP With concrete field paving of invert

General Notes - Figures 1008-1 through 1008-9

Thickness

The following table shows the available commercial thicknesses for metallic coated steel and the corresponding gage number:

Metal Thickness (Inches)

Gage Number

0.064 160.079 140.109 120.138 100.168 80.188 70.218 50.249 30.280 1

The maximum available sheet thickness for aluminum coated corrugated steel pipe (707.01, 707.02, 707.05, 707.07; all with aluminum coating) or polymer coated corrugated steel pipe (707.04) is 0.138.

Minimum Cover

The minimum cover is measured from the top of the pipe or pipe-arch to the top of subgrade; however, in no installation shall the distance from the top of the pipe or pipe-arch to the top of the wearing surface or finished grade be less than the figure values plus 6 inches.

Maximum Cover

The maximum height of cover is measured from the top of the pipe or pipe-arch, to the top of the wearing surface.

Pipe Diameter

(inches)

12

15

18

21

24

27

30

36

42

48

54

60

66

72

78

84

36

42

48

54

60

66

72

78

84

90

96

102

108

114

120

Minimum Cover

18

MINIMUM HEIGHT OF COVER TABLE 1CORRUGATED STEEL PIPE

1008-1

Pipe

Des

igna

tion

HEIGHT OF COVER TABLE 1

(inches)

12

12

18

12

Revised July 2014

Corrugated Steel Pipe

Reference Section1008.1.2

12

12

12

12

12

12

12

12

12

12

12

18

12

12

12

12

12

12

18

707.

01, 7

07.0

4, 7

07.0

5, 7

07.1

1 an

d 70

7.13

(2

2/3

" x 1

/2" C

orru

gatio

ns)

707.

02, 7

07.0

4, 7

07.0

7, 7

07.1

1 an

d 70

7.14

(5" x

1" C

orru

gatio

ns)

12

12

12

12

12

12

12

Pipe DimentionsSpan X Rise

(inches)

17 x 13

21 x 15

24 x 18

28 x 20

35 x 24

42 x 29

49 x 33

57 x 38

64 x 43

71 x 47

77 x 52

83 x 57

40 x 31

46 x 36

53 x 41

60 x 46

66 x 51

73 x 55

81 x 59

87 x 63

95 x 67

103 x 71

112 x 75

117 x 79

128 x 83

137 x 87

142 x 91

Revised July 2014

1008-2Reference Section

1008.1.2

Pipe

12

12

(inches)

12

12

Corrugated Steel Pipe Arches

Minimum Cover

15

15

15

15

12

12

12

18

18

21

18

18

18

24

707.

01, 7

07.0

4, 7

07.0

5, 7

07.1

1 an

d 70

7.13

(2 2

/3" x

1/2

" Cor

ruga

tions

)70

7.02

, 707

.04,

707

.07,

707

.11

and

707.

14

(5" x

1" C

orru

gatio

ns)

21

24

24

MINIMUM HEIGHT OF COVER TABLE 2 CORRUGATED STEEL PIPE ARCHES

Pipe

Des

igna

tion

HEIGHT OF COVER TABLE 2

12

15

12

12

12

12

Pipe Pipe Diameter Diameter

(inches) (feet-inches)

60 5'0"

66 5'6"

72 6'0"

78 6'6"

84 7'0"

90 7'6"

96 8'0"

102 8'6"

108 9'0"

114 9'6"

120 10'0"

126 10'6"

132 11'0"

138 11'6"

144 12'0"

150 12'6"

156 13'0"

162 13'6"

168 14'0"

174 14'6"

180 15'0"

186 15'6"

192 16'0"

198 16'6"

204 17'0"

210 17'6"

216 18'0"

222 18'6"

228 19'0"

234 19'6"

240 20'0"

246 20'6"

252 21'0"

Revised July 2014

1008-3Reference Section

1008.1.2

HEIGHT OF COVER TABLE 3

707.03 Structural Plate Corrugated Steel Pipe

Minimum Cover

(inches)

12

12

12

12

12

12

12

18

18

18

18

18

18

18

18

30

24

24

24

24

24

24

24

24

30

36

30

30

30

30

30

MINIMUM HEIGHT OF COVER TABLE 3 707.03 STRUCTURAL PLATE CORRUGATED

STEEL PIPE

36

30

Pipe

Dimentions

Span X Rise

(feet-inches)

6'1" x 4'7"

6'4" x 4'9"

6'9 x 4'11"

7'0" x 5'1"

7'3" x 5'3"

7'8" x 5'5"

7'11" x 5'7"

8'2" x 5'9"

8'7" x 5'11"

8'10" x 6'1"

9'4" x 6'3"

9'6" x 6'5"

9'9" x 6'7"

10'3" x 6'9"

10'8" x 6'11"

10'11" x 7'1"

11'5" x 7'3"

11'7" x 7'5"

11'10" x 7'7"

12'4" x 7'9"

12'6" x 7'11"

12'8" x 8'1"

12'10" x 8'4"

13'5" x 8'5"

13'11" x 8'7"

14'1" x 8'9"

14'3" x 8'11"

14'10" x 9'1"

15'4" x 9'3"

15'6" x 9'5"

15'8" x 9'7"

15'10" x 9'10"

16'5" x 9'11"

16'7" x 10'1"

Revised January 2013

MINIMUM HEIGHT OF COVER TABLE 4

707.03 STRUCTURAL PLATE

CORRUGATED STEEL PIPE ARCHES

1008-4

Reference Section

1008.1.2

HEIGHT OF COVER TABLE 4

707.03 Structural Plate Corrugated Steel Pipe (18-inch Corner Radius)

Minimum Cover

(inches)

18

18

18

18

18

18

18

18

18

18

18

18

18

18

18

18

18

18

18

18

18

24

24

24

24

24

24

24

24

24

24

36

36

24

Pipe

Dimentions

Span X Rise

(feet-inches)

13'3" x 9'4"

13'6" x 9'6"

14'0" x 9'8"

14'2" x 9'10"

14'5" x 10'0"

14'11" x 10'2"

15'4" x 10'4"

15'7" x 10'6"

15'10" x 10'8"

16'3" x 10'10"

16'6" x 11'0"

17'0" x 11'2"

17'2" x 11'4"

17'5" x 11'6"

17'11" x 11'8"

18'1" x 11'10"

18'7" x 12'0"

18'9" x 12'2"

19'3" x 12'4"

19'6" x 12'6"

19'8" x 12'8"

19'11" x 12'10"

20'5" x 13'0"

20'7" x 13'2"

Revised January 2013

MINIMUM HEIGHT OF COVER TABLE 5

707.03 STRUCTURAL PLATE CORRUGATED

STEEL PIPE ARCHES

1008-5

Reference Section

1008.1.2

HEIGHT OF COVER TABLE 5

707.03 Structural Plate Corrugated Steel Pipe (31-inch Corner Radius)

Minimum Cover

(inches)

24

24

24

24

24

24

24

24

24

36

36

36

36

36

36

36

36

36

36

36

36

36

36

36

Pipe

Diameter

(inches)

18

21

24

30

36

42

48

54

60

66

72

78

84

90

Revised January 2013

Reference Section

1008.1.2

HEIGHT OF COVER TABLE 6

Corrugated Steel Spiral Rib Pipe

MINIMUM HEIGHT OF COVER TABLE 6

FOR CORRUGATED STEEL

SPIRAL RIB PIPE

1008-6

707.12

(3/4" x 7 1/2" Corrugations)

18

18

18

12

12

18

18

15

15

15

15

(inches)

12

12

12

Pipe

Designation

Minimum Cover

General Notes - Figures 1008-10 through 1008-14

Minimum Cover

See Section 1008.2.2

Maximum Cover

The maximum height of cover is measured from the top of the pipe or elliptical pipe to the top of the wearing surface.

Pipe

Diameter

(inches)

12

15

18

21

24

27

30

36

42

48

54

60

66

72

78

84

90

96

102

108

114

120

126

132

144

4

2.5

2.75

3

3.25

3.5

7.5

4.5

5

5.5

6

6.5

7

8.5

9

9.5

10.5

11

12

(inches)

2

2.25

8

8

8.5

Revised January 2013

REINFORCED CONCRETE

CIRCULAR PIPE

1008-11

Reference Section

1008.2.1

706.02 Reinforced Concrete Circular Pipe

Wall Thickness

10

Equivalent Pipe Equivalent Pipe

Round Rise X Span Round Rise X Span

Diameter Diameter

(inches) (inches) (inches) (inches) (inches) (inches)

18 14x23 2.75 36 45x29 4.5

24 19x30 3.25 42 53x34 5

27 22x34 3.5 48 60x38 5.5

30 24x38 3.75 54 68x43 6

36 29x45 4.50 60 76x48 6.5

42 34x53 5 66 83x53 7

48 38x60 5.5 72 91x58 7.5

54 43x68 6 78 98x63 8

60 48x76 6.5 84 106x68 8.5

66 53x83 7 90 113x72 9

72 58x91 7.5 96 121x77 9.5

78 63x98 8 102 128x82 9.75

84 68x106 8.5 108 136x87 10

90 72x113 9 114 143x92 10.5

96 77x121 9.5 120 151x97 11

102 82x128 9.75 132 166x106 12

108 87x136 10 144 180x116 13

114 92x143 10.5

120 97x151 11

132 106x166 12

144 116x180 13

Wall

Thickness

Wall

Thickness

Revised January 2013

REINFORCED CONCRETE

ELLIPTICAL PIPE

1008-12

Reference Section

1008.2.1

706.04 Reinforced Concrete Elliptical Pipe

Box

Span 4 5 6 7 8 9 10

(ft)

8 10 10 10 10 - - -

10 - 10 10 10 10 10 -12 10 - 10 - 10 - 10

14 10 10 10 10 10 10 10

16 10 10 10 10 10 10 10

18 10 10 10 10 10 10 10

20 10 10 10 10 10 10 10

Revised January 2014

1008-14Reference Section

1008.5

MAXIMUM ALLOWABLE HEIGHT OF COVER - REINFORCED CONCRETE

BOX CULVERTS

706.05 Precast Reinforced Concrete Box Culverts

Box Rise (ft)

*Height of Fill (Maximum)

Approval of OHE is required for sizes other than those listed above.

Spans 14' or greater shall be designed for HL93 live load with an additonal 60psf for a future wearing surface.

General Notes - Figures 1008-15 through 1008-19

Thickness

The following table shows the available commercial metal thicknesses for aluminum pipe:

Metal Thickness(Inches)

707.21, 707.22 & 707.24

Metal Thickness(Inches)707. 23

0.060 0.1000.075 0.1250.105 0.1500.135 0.1750.164 0.200

0.2250.250

Minimum Cover

The minimum cover is measured from the top of the pipe or pipe arch to the top of subgrade; however, in no installation shall the distance from the top of the pipe or pipe arch to the top of the wearing surface or finished grade be less than the figure values plus 6 inches.

Maximum Cover

The maximum height of cover is measured from the top of the pipe or pipe arch to the top of the wearing surface.

Table of Contents(Revised April 2017)

1100 Drainage Design Procedures1101 Estimating Design Discharge .........................................................................................................11-1

1101.1 General...........................................................................................................................11-11101.2 Procedures .....................................................................................................................11-1

1101.2.1 Statistical Methods .........................................................................................11-11101.2.2 Rational Method .............................................................................................11-11101.2.3 Coefficient of Runoff .......................................................................................11-31101.2.4 Rainfall Intensity .............................................................................................11-4

1102 Open Water Carriers ......................................................................................................................11-41102.1 General...........................................................................................................................11-41102.2 Types of Carriers ............................................................................................................11-4

1102.2.1 Standard Roadway (Roadside) Ditches .........................................................11-41102.2.2 Special Ditches...............................................................................................11-41102.2.3 Median Ditches...............................................................................................11-51102.2.4 Channel Relocations ......................................................................................11-51102.2.5 Channel Linings and Bank Stabilization .........................................................11-5

1102.3 Ditch Design Criteria - Design Traffic Exceeding 2000 ADT ..........................................11-61102.3.1 Design Frequency ..........................................................................................11-61102.3.2 Ditch Protection ..............................................................................................11-61102.3.3 Roughness .....................................................................................................11-81102.3.4 Catch Basin Types .........................................................................................11-81102.3.5 Calculated Catch Basin Spacing ....................................................................11-91102.3.6 Arbitrary Maximum Catch Basin Spacing .......................................................11-9

1102.4 Ditch Design Criteria - Design Traffic of 2000 ADT or Less ...........................................11-91102.4.1 Design Frequency ..........................................................................................11-91102.4.2 Shear Stress Protection..................................................................................11-91102.4.3 Roughness ...................................................................................................11-101102.4.4 Catch Basin Types .......................................................................................11-10

1102.5 Design Aids for Ditch Flow Analysis .............................................................................11-101102.5.1 Earth Channel Charts ...................................................................................11-101102.5.2 Rectangular Channel Charts ........................................................................11-10

1103 Pavement Drainage......................................................................................................................11-101103.1 General.........................................................................................................................11-101103.2 Design Frequency ........................................................................................................11-111103.3 Estimating Design Discharge .......................................................................................11-111103.4 Capacity of Pavement Gutters......................................................................................11-121103.5 Pavement Flow Charts .................................................................................................11-121103.6 Bypass Charts for Continuous Pavement Grades........................................................11-12

1103.6.1 Curb Opening Inlets......................................................................................11-131103.6.2 Grate or Combination Grate and Curb Opening Inlet ...................................11-13

1103.7 Grate Catch Basins and Curb Opening Inlets in Pavement Sags ................................11-131103.8 Bridge Deck Drainage ..................................................................................................11-131103.9 Slotted Drains and Trench Drains ................................................................................11-15

1104 Storm Sewers ...............................................................................................................................11-151104.1 General.........................................................................................................................11-151104.2 Design Considerations .................................................................................................11-16

1104.2.1 Storm Sewer Depth ......................................................................................11-161104.2.2 Storm Sewer Access ....................................................................................11-171104.2.3 Rock Excavation for Storm Sewer................................................................11-17

1104.3 Layout Procedure .........................................................................................................11-171104.3.1 Plan ..............................................................................................................11-171104.3.2 Profile ...........................................................................................................11-18

1104.4 Storm Sewer Design Criteria ........................................................................................11-181104.4.1 Design Frequency ........................................................................................11-18

1104.4.2 Hydraulic Grade Line....................................................................................11-181104.4.3 Coefficient of Runoff .....................................................................................11-181104.4.4 Time of Concentration ..................................................................................11-191104.4.5 Pipe Roughness Coefficient .........................................................................11-191104.4.6 Minimum Storm Sewer Pipe Size .................................................................11-191104.4.7 Maximum Storm Sewer Slope ......................................................................11-19

1104.5 Hydraulic Design Procedure.........................................................................................11-191104.6 Combined Sanitary Sewer Separation .........................................................................11-19

1105 Roadway Culverts ........................................................................................................................11-201105.1 General.........................................................................................................................11-201105.2 Stream Protection.........................................................................................................11-20

1105.2.1 Bankfull Discharge Design ...........................................................................11-211105.2.2 Depressed Culvert Inverts ............................................................................11-221105.2.3 Paved Depressed Approach Aprons ............................................................11-231105.2.4 Flood Plain Culverts .....................................................................................11-231105.2.5 Energy Control Structures ............................................................................11-23

1105.3 Types of Culvert Flow...................................................................................................11-241105.4 Design Procedure.........................................................................................................11-24

1105.4.1 General .........................................................................................................11-241105.4.2 Hydraulic Analysis ........................................................................................11-24

1105.5 Use of Nomographs......................................................................................................11-251105.5.1 Outlet Control ...............................................................................................11-251105.5.2 Inlet Control ..................................................................................................11-25

1105.6 Design Criteria..............................................................................................................11-251105.6.1 Design Frequency ........................................................................................11-251105.6.2 Maximum Allowable Headwater ...................................................................11-251105.6.3 Method Used to Estimate Storm Discharge .................................................11-251105.6.4 Scale of Topographic Mapping Used to Delineate Contributing Drainage Areas.....................................................................................................................................11-251105.6.5 Manning’s Roughness Coefficient “n”...........................................................11-261105.6.6 Entrance Loss Coefficient “ke” ......................................................................11-261105.6.7 Minimum Cover ............................................................................................11-261105.6.8 Maximum Cover ...........................................................................................11-261105.6.9 Maximum Allowable Outlet Velocity .............................................................11-261105.6.10 Headwall Type............................................................................................11-261105.6.11 Contacts With County Engineer .................................................................11-261105.6.12 Minimum Pipe Size.....................................................................................11-261105.6.13 Ordinary High Water Mark..........................................................................11-26

1105.7 Special Considerations.................................................................................................11-271105.7.1 Tailwater .......................................................................................................11-271105.7.2 Multiple Cell Culverts....................................................................................11-271105.7.3 Improved Inlets .............................................................................................11-27

1106 End Treatments ............................................................................................................................11-281106.1 General.........................................................................................................................11-28

1106.1.1 Usage ...........................................................................................................11-281106.1.2 End Treatment Grading ................................................................................11-28

1106.2 Headwall Types ............................................................................................................11-291106.2.1 Half-Height Headwalls ..................................................................................11-291106.2.2 Full-Height Headwalls...................................................................................11-29

1106.3 Concrete Apron ............................................................................................................11-291107 Rock Channel Protection (RCP)...................................................................................................11-30

1107.1 General.........................................................................................................................11-301107.2 Culvert RCP Types.......................................................................................................11-301107.3 Bridge RCP...................................................................................................................11-30

1108 Agricultural Drainage ....................................................................................................................11-301108.1 Farm Drain Crossings...................................................................................................11-301108.2 Farm Drain Outlets .......................................................................................................11-31

1109 Longitudinal Sewer Location ........................................................................................................11-31

1109.1 Under Pavement...........................................................................................................11-311109.2 Under Paved Shoulder .................................................................................................11-311109.3 Approval .......................................................................................................................11-31

1110 Reinforced Concrete Radius Pipe and Box Sections ...................................................................11-311110.1 General.........................................................................................................................11-31

1111 Sanitary Sewers ...........................................................................................................................11-321111.1 General.........................................................................................................................11-321111.2 Manholes ......................................................................................................................11-32

1112 Notice of Intent (NOI)....................................................................................................................11-321112.1 General.........................................................................................................................11-321112.2 Routine Maintenance Project .......................................................................................11-331112.3 Watershed Specific NOI Requirements........................................................................11-34

1113 Erosion Control at Bridge Ends ....................................................................................................11-341113.1 General.........................................................................................................................11-341113.2 Corner Cone .................................................................................................................11-35

1114 Temporary Sediment and Erosion Control ...................................................................................11-351114.1 General.........................................................................................................................11-351114.2 Cost Estimate for Temporary Sediment and Erosion Control.......................................11-35

1115 Post Construction Storm Water Structural Best Management Practices......................................11-351115.1 General.........................................................................................................................11-351115.2 Project Thresholds for Post-Construction BMP............................................................11-361115.3 Water Quality and Water Quantity Treatment ..............................................................11-361115.4 Water Quality Volume...................................................................................................11-371115.5 Water Quality Flow .......................................................................................................11-381115.6 Project Type - Redevelopment and New Construction.................................................11-38

1115.6.1 Redevelopment Projects ..............................................................................11-381115.6.2 New Construction Projects ...........................................................................11-381115.6.3 Pedestrian Facilities and Shared Use Paths ................................................11-381115.7 Treatment Requirements for Projects..............................................................11-39

1116 BMP Selection and Submittals .....................................................................................................11-401116.1 BMP Selection ..............................................................................................................11-401116.2 BMP Submittals ............................................................................................................11-40

1117 BMP Toolbox ................................................................................................................................11-411117.1 Manufactured Systems.................................................................................................11-411117.2 Vegetation Based BMP ................................................................................................11-42

1117.2.1 Vegetated Filter Strip....................................................................................11-421117.2.2 Vegetated Biofilter ........................................................................................11-43

1117.3 Extended Detention ......................................................................................................11-451117.3.1 Detention Basin ............................................................................................11-451117.3.2 Underground Detention ................................................................................11-481117.3.3 Design Check Discharge ..............................................................................11-49

1117.4 Retention Basin ............................................................................................................11-491117.4.1 Water Quality Basin and Weir ......................................................................11-50

1117.5 Bioretention Cell ...........................................................................................................11-501117.5.1 Level bioretention cell in an open area with grassed side slopes.................11-501117.5.2 Sloped bioretention cell within a grassed ditch.............................................11-501117.5.3 Bioretention Cell Design Procedure .............................................................11-51

1117.6 Infiltration ......................................................................................................................11-521117.6.1 Infiltration Trench..........................................................................................11-531117.6.2 Infiltration Basin ............................................................................................11-54

1117.7 Constructed Wetlands ..................................................................................................11-551117.8 Stream Grade Control ..................................................................................................11-56

1118 Bridge Hydraulics .........................................................................................................................11-561118.1 General.........................................................................................................................11-561118.2 Hydrology and Hydraulics (H&H) Report......................................................................11-56

1118.2.1 Analysis ........................................................................................................11-571118.2.2 Narrative .......................................................................................................11-57

1100 Drainage Design Procedures

April 2017 11- 1

1101 Estimating Design Discharge

1101.1 General

In order to properly design highway drainage facilities, it is essential that a reasonable estimate be made of the design and check discharges. Some of the more important factors affecting runoff are duration, intensity and frequency of rainfall; and the size, imperviousness, slope, and shape of the drainage area.

Use suitable topographic mapping to determine the contributing drainage area. For drainage areas over 100 acres, a 7.5 minute U.S. Geological Survey Quadrangle will ordinarily suffice. For smaller areas, or where discharges are calculated using the rational method, smaller scale maps (1”=50’ to 1”=800’) may be more appropriate.

Other methods that use Geographic Information Systems (GIS) such as USGS Stream Stats are acceptable. The use of contours generated from LiDAR data collected through the Ohio Statewide Imagery Program (OSIP) is also acceptable.

A proper evaluation should be made of the land use throughout the drainage area. Changes in land use within the drainage area which will occur in the immediate future shall be taken into account when determining design discharges. However, probable land use changes beyond this should not be assumed when determining design discharges. It is the responsibility of the local permitting/zoning agency to ensure proper land and water management techniques are utilized. These techniques will minimize the adverse effects of a change in land use. Post Construction Storm Water Best Management Practices are used on roadway projects in an effort to minimize quality and quantity impacts as well (see section 1115). 1101.2 Procedures

1101.2.1 Statistical Methods

See Section 1003.

1101.2.2 Rational Method

The rational method is considered to be more reliable for estimating runoff from small drainage areas, less than the acreage for the USGS Regions; and for areas that contribute overland flow and shallow concentrated flow to the roadway ditch or pavement. The design discharge “Q” is obtained from the equation:

Q = CiA

Where:Q = Discharge in cubic feet per second C = Coefficient of runoffI = Average rainfall intensity in inches per hour, for a given

storm frequency and for a duration equal to the time of concentration.

A = Drainage area in acres

The time of concentration is the time required for runoff to flow from the most remote point of the drainage area to the point of concentration. The point of concentration could be a culvert, catch basin or the checkpoint in a roadway ditch used to determine the need for velocity protection. Time of concentration is designated by “tc” and is the summation of the time of overland flow “to”, the time of shallow concentrated flow "ts" and the time of pipe or open channel flow “td”.

Drainage Design Procedures

11-2 April 2017

Overland flow is that flow which is not carried in a discernible channel and maintains a uniform depth across the sloping surface. It is often referred to as sheet flow. The time of overland flow may be obtained from Figure 1101-1, a similar overland flow chart, or from the equation:

to 1.8(1.1- C) L1/2

s1/3

Where:to = Time of overland flow in minutesC = Coefficient of runoffL = Distance to most remote location in

drainage area in feet (300 ft. max)s = Overland slope (percent)

These methods should not be used to determine the time of travel for gutter, swale, or ditch flow.

This equation and Figure 1101-1 assume a homogeneous drainage area. Where the overland flow area is composed of segments with varying cover and/or slopes, the summation of the time of concentration for each segment will tend to over-estimate the overland flow time, “to”. In this case it may be more appropriate to use an average runoff coefficient "C" and an average ground slope in the Overland Flow Chart.

Sheet flow is assumed to occur for no more than 300 feet after which water tends to concentrate in rills and then gullies of increasing proportion. This type of flow is classified as shallow concentrated flow. The velocity of shallow concentrated flow can be estimated using the following relationship:

V = 3.281ks0.5

Where:V = Velocity in fpsk = Intercept coefficient

(see Table 1101-1)s = Overland slope (percent)

Table 1101-1

Types of SurfaceIntercept

Coefficient “k”

Forest with heavy ground litter 0.076 Min. tillage cultivated; woodland 0.152 Short grass pasture 0.213 Cultivated straight row 0.274 Poor grass; untilled 0.305 Grassed waterways 0.457 Unpaved area; bare soil 0.491 Paved area 0.619

Shallow concentrated flow generally empties into pipe systems, drainage ditches, or natural channels. The velocity of flow in an open channel or pipe can be estimated using the Manning's equation.

Drainage Design Procedures

April 2017 11-3

The travel time for both shallow concentrated flow and open channel or pipe flow is calculated as follows:

ts or td = L60V

Where:ts = Travel time for shallow concentrated

flow in minutestd = Travel time for open channel or pipe

flow in minutesL = Flow length in feet V = Velocity in fps

Where a contributing drainage area has its steepest slope and/or highest "C" value in the sub-area nearest the point of concentration, the rational method discharge for this sub-area may be greater than if the entire contributing drainage area is considered. The maximum runoff rate for a sub-area should be considered only if greater than that for the entire area. 1101.2.3 Coefficient of Runoff

The coefficient of runoff is a dimensionless decimal value that estimates the percentage of rainfall that becomes runoff. The recommended values for the coefficient of runoff for various contributing surfaces are shown in Table 1101-2. Where two values are shown, the higher value ordinarily applies to the steeper slopes.

For Residential areas, lot size should also be considered in choosing the appropriate value for the coefficient of runoff. Generally, a higher value should be associated with smaller lots and a lower value should be associated with larger lot sizes. The selected coefficient should be based upon an estimation of the typical slope, lot size, and lot development.

The total width contributing flow to a given point usually consists of surfaces having a variable land cover and thereby requires a weighted coefficient of runoff “C”. The weighted coefficient is obtained by averaging the coefficients for the different types of contributing surfaces, as noted in the following example:

Table 1101-2

Types of Surface Coefficient of Runoff “C”

Pavement & paved shoulders 0.9 Berms and slopes 4:1 or flatter 0.5 Berms and slopes steeper than 4:1 0.7 Contributing areas Residential (single family) 0.3-0.5 Residential (multi-family) 0.4-0.7 Woods 0.3 Cultivated 0.3-0.6

Contributing Width “W” Land Use “C” “CW”

20 feet Paved Area 0.9 1840 feet Earth Berms & Slopes 0.7 28

140 feet Residential Area 0.6 84200 feet Summations 130

Weighted “C” = 130/200 = 0.65

Drainage Design Procedures

11-4 April 2017

1101.2.4 Rainfall Intensity

The average rainfall intensity “i” in inches per hour may be obtained from the Intensity-Duration-Frequency curves shown on Figure 1101-2. Each set of curves applies to a specific geographic area, A, B, C, or D as shown on the Rainfall Intensity Zone Map, Figure 1101-3. The geographic areas were established from an analysis of rainfall records obtained from Weather Bureau stations in Ohio. Some political subdivisions may have developed curves for their specific area similar to Figure 1101-2. Such curves may be based on a much longer period of record and provide more reliable information. Any local curves proposed by the designer should be cleared with the Office of Hydraulic Engineering (OHE) prior to incorporating that information in the drainage calculations.

1102 Open Water Carriers

1102.1 General

Open water carriers generally provide the most economical means for collecting and conveying surface water contributing to the roadway. The required capacity of a water carrier involves a determination of the velocity and depth of flow for a given discharge. These characteristics can best be obtained from charts that are based on Manning’s equation. Channel flow charts have been prepared for all the common water carrier shapes and are included in the Drainage Design Aids. A ditch computation sheet similar to that provided in the Appendix shall be used to perform or summarize ditch calculations. As a guideline, the relative minimum roadway ditch grades should be 0.50% with a recommended absolute minimum of 0.25%. Lower grades may be used on large channels as necessary. Open water carriers should maintain a constant slope wherever possible. The proper location of a ditch outfall is quite important. Existing drainage patterns should be perpetuated insofar as practicable. Care should be taken to not capture an existing stream with the roadside ditch. If this is necessary, the designed ditch shall be in accordance to Section 1102.2.4.

1102.2 Types of Carriers

1102.2.1 Standard Roadway (Roadside) Ditches

The various roadside ditches shown in Volume I, Roadway Design, have proven to be safe and to provide adequate flow capacity. A ditch is considered to be standard when the centerline is parallel to the edge of the pavement and the flowline is a uniform distance below the edge of pavement. A modification of the above is required when the grade of the pavement is too flat to provide acceptable ditch flow, thereby creating the need for a special ditch. Channel charts, Drainage Design Aid Figures 1100-1 through 1100-10, are included for use in determining velocity and depth of flow for standard ditches having variable side slopes.

1102.2.2 Special Ditches

Special ditches other than the modified standard roadway ditch described in Section 1102.2.1 above, include the following:

A. The steep ditch beyond the toe of the embankment used to carry the flow from a cut section to the valley floor.

B. Toe of fill ditch which is separated from the toe of fill by a minimum 10 foot wide bench, having a minimum transverse slope of ½ inch per foot toward the ditch.

C. Deep parallel side ditches separated from the pavement by a wide bench or earth barrier.

The special ditches described in A, B and C above are ordinarily trapezoidal in shape and appropriate charts for the hydraulic analysis are included in this section of the manual or in the FHWA publication “Design Charts for Open Channel Flow”’ Hydraulic Design Series No. 3. It is required that the calculated flowline elevation be shown on each special ditch cross section.

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1102.2.3 Median Ditches

The median ditches that are an integral part of all earth medians have the same shape and capacity features as the standard roadside radius ditch and the appropriate ditch chart is applicable for the hydraulic analysis. The fully depressed earth median provides adequate hydraulic capacity and the appropriate flow charts in the Drainage Design Aid Figures 1100-11, 1100-12 and 1100-13 have been developed for that shape. The rounding shown on the charts varies from 8 feet to 4 feet, depending on the width of the median. The slight discrepancy in the rounding from that shown in Volume I, Roadway Design, is not considered to affect the accuracy of the charts.

1102.2.4 Channel Relocations

Major channel relocations should be avoided. However, if it becomes necessary to relocate a channel adhere to the following:

The design year frequency used for channel relocations shall be that given in Section 1004.2. All channel relocations shall carefully be designed to preclude erosion or unreasonable changes in the environment.

Whenever possible, channel relocations shall be restricted to the downstream end of proposed culverts.

The relocated channel shall be of a similar cross-section. Where the existing channel exhibits a two-stage cross section morphology, it shall be replaced with like kind. The two-stage channel is comprised of two distinct areas. The first of these is a meandering bankfull width that carries the channel-forming discharge. The second area is the flood plain width. See Figure 1102-2 for a graphical representation of the major channel features. The proposed channel should be designed such that it matches the existing channel as closely as possible in regards to existing geomorphic conditions (e.g., channel slope and length, velocity, depth of flow, cross-sectional geometry, channel sinuosity, energy dissipation, etc.). The existing channel geometry and physical characteristics should be established from reference reaches and idealized geometry. The reference reaches should be selected from stable channel reaches close to the relocated section or in locations with similar watershed and valley conditions.

The relocated channel should be designed to duplicate the existing hydraulic properties for the bankfull design frequency. The flood clearance criteria given in Section 1005 should also be met.

Additional information on the design of relocated channels can be found in the United States Department of Agriculture publication, “Stream Corridor Restoration: Principles, Practices and Processes”. The principals given in this publication utilize idealized channel geometry. The actual design should be refined using the channel geometry and physical characteristics of reference reaches. 1102.2.5 Channel Linings and Bank Stabilization

The use of soil bioengineering should be used to stabilize banks for relocated or impacted channels when practicable. Native plant species should be used when feasible.

Bank stabilization using bioengineering is covered in the previously referenced USDA publication as well as the AASHTO Model Drainage Manual and the USDA Engineering Field Handbook, chapter 16, part 650. The design procedures and methods for determining the effectiveness of the traditional channel linings are covered in the Federal Highway Administration Hydraulic Engineering Circular No. 15 “Design of Stable Channels with Flexible Linings”.

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1102.3 Ditch Design Criteria - Design Traffic Exceeding 2000 ADT

1102.3.1 Design Frequency

Determine the depth of flow using a 10-year frequency storm, and determine the shear stress and width of the ditch lining (if required) using a 5-year frequency storm. Where a flexible ditch lining is required for calculated stresses exceeding the allowable for seed, the minimum width of the lining shall be 7.5 feet. Additional required width is in increments of 3.5 feet. The installed width of all ditch linings is centered on the flow line of the ditch. The depth of flow shall be limited to an elevation 1 foot below the edge of pavement for the design discharge. The depth of flow in toe of slope ditches shall be further limited such that the design year discharge does not overtop the ditch bank.

1102.3.2 Ditch Protection

The shear stress for the five-year frequency storm shall not exceed the values shown in Table 1102-1 for the various flexible linings.

Table 1102-1Permanent Protection

Protective Lining Allowable Shear Stress (lbs/ft2)

Seed (659) 0.40Sodding, Ditch

Protection (660) 1.0

Temporary ProtectionDitch Erosion Protection

Mat Type___ (670)A 1.25B 1.50C 2.0E 2.25F 0.45G 1.75

The temporary linings will reach a value of 1.0 psf upon vegetation establishment. Use the temporary lining shear stress values in Table 1102-1 on a temporary basis only (6 months or less).

Calculate the actual shear stress by the following equation:

ac = 62.4 ∙ D ∙ S

Where: D = Water surface depth ft S = Channel slope ft/ft ac = Actual shear stress lbs/ft2

If the calculated shear stress exceeds that shown in table 1102-1 then use the following permanent shear stress values within the stated limitations:

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A. Seeding and Erosion Control with Turf Reinforcing Mat (Supplemental Specification 836) where the ditch slope is less than 10%. Allowable shear stress for each type is as follows:

Turf Reinforcing Mat Shear StressType Allowable Shear Stress (lbs/ft2)

1 22 33 5

B. Type B, C or D Rock Channel Protection may be used to line the ditch if the nearest point of the lining is outside the design clear zone or located behind guardrail or barrier. The actual shear stress is based upon the parameters of the channel slope and depth of flow for the 5-year discharge. The shear equation is valid for discharges less than 50 cfs with slopes less than 10%. Allowable shear stress for each type is as follows:

RCP Shear StressType Allowable Shear Stress (lbs/ft2)

B 6C 4D 2

C. Type B or C RCP may be utilized for lining ditches on steep grades (slopes from 10%- 25%) that carry flow from the end of a cut section down to the valley floor. Use HEC-15 procedures with a safety factor of 1.5 for steep gradient channels (refer to HEC-15). Contact OHE for further guidance of RCP usage for 5-year discharges greater than or equal to 50 cfs.

D. Tied concrete block mat protection (601) may be used for slopes and swales with 2:1 or flatter side slopes with profile grades at 25% or less. The matting may be used within the clear zone provided that the top of the blocks are flush with the finished grade. Install per the manufacturers recommendations. The allowable shear stress for each type is as follows:

Tied Concrete Block Mat Shear StressType Allowable Shear Stress (lbs/ft2)

1 32 53 7

E. Articulating concrete block revetment system (601) may be used for slopes and channels with 2:1 or flatter side slopes. The revetment may be used within the clear zone provided that the top of the blocks are flush with the finished grade. Install per the manufacturers recommendations. The allowable shear stress for each type is as follows:

Articulating Concrete Block Revetment System Shear Stress

Type Allowable Shear Stress (lbs/ft2)1 172 203 23

F. A concrete lining should be considered only as a last resort. Contact OHE, before using a concrete lining.

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1102.3.3 Roughness

Suggested values for Manning’s Roughness Coefficient “n” for the various types of open water carriers are listed in Table 1102-2.

Table 1102-2Manning’s Roughness Coefficient

Type of Lining n Bare Earth 0.02 Seeded 0.03 Sod 0.04 Item 670 0.04 Concrete 0.015 Bituminous 0.015 Grouted Riprap 0.02 Tied Concrete Block Mat 0.03

Rock Channel Protection 0.06 for ditches 0.04 for large channels

1102.3.4 Catch Basin Types

The Standard No. 4, 5, and 8 Catch Basins are suitable for the standard roadside designs covered in Volume I, Roadway Design. The tilt built into the basin top provides a self-cleaning feature when the basins are used on continuous grades and the wide bar spacing minimizes clogging possibilities, thereby resulting in an efficient design. The bases of the 4, 5 and 8 Catch Basins can be expanded to accommodate larger diameter conduits by specifying Standard Construction Drawing CB-3.4. The bar spacing can be decreased, when desirable for safety reasons, by specifying Grate “E” for the No. 4 and Grate “B” for the No. 5. Provide 150 feet of ditch erosion protection upstream of all No. 4, 5 and 8 Catch Basins, regardless of velocity. The following catch basin types are generally recommended based on the size and shape of the ditch.

A. Standard No. 4 for depressed medians wider than 40 feet.

B. Standard No. 5 for 40 foot radius roadside or median ditches. (Use Grate “B” where pedestrian traffic may be expected.)

C. Standard No. 8 for 20 foot radius roadside or depressed medians 40 feet or less in width.

D. Standard No. 2-2-A may be used in trapezoidal toe ditches where the basin is located in a rural area. The basin should also be located outside the design clear zone or behind guardrail where the protruding feature of the basin is not objectionable. The capacity of the side inlet catch basin window, for unsubmerged conditions, may be determined by the standard weir equation:

Q = C ∙ L ∙ H3/2

Where C is a weir coefficient, generally 3.0, L is the length of opening in feet, H is the distance from the bottom of the window to the surface of the design flow in feet. The catch basin grate is considered as an access point for the storm sewer and its capacity to admit flow is ignored for continuous grades.

E. Standard No. 2-2-B should be used where minor, non-clogging flows are involved such as yard sections and the small triangular area created by the guardrail treatment for a depressed median at bridge terminals. Standard No. 2-3 through No. 2-6 catch basins should be provided where a larger base is required to accommodate pipes larger than 21 inches in span or sewer junctions, or where a No. 2-2-B catch basin will not provide adequate access to the sewer.

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F. In urban areas, Standard Side Ditch Inlets should be used to drain small areas of trapped water behind curbs and/or between driveways.

1102.3.5 Calculated Catch Basin Spacing

Catch basins must be provided to intercept flow from open water carriers when the depth of flow or velocity exceeds the maximum allowable for the design storm for all highway classifications. The standard ditch catch basins, designated Catch Basin No. 4, Catch Basin No. 5, and Catch Basin No. 8, include an earth dike. The dike is approximately 12 inches above the flowline of the grate, immediately downstream from the catch basin and serves to block the flow on continuous grades and create a sump condition.

When the calculated depth of flow or velocity exceeds the maximum allowable at the checkpoint in the ditch, a catch basin or ditch lining will be required. However, the capacity of the catch basin may be less than the capacity of the ditch and thereby control the catch basin spacing. Figure 1102-1 may be used to check the capacity of a catch basin grate in a sump. To use Figure 1102-1, the calculated discharge at the ditch checkpoint shall be doubled to compensate for possible partial clogging of the grate.

In cut sections, the accumulated ditch flow shall be carried as far as the capacity, allowable depth, or velocity of flow will permit. The first catch basin in the roadside or median ditch will determine the need for a storm sewer system required for the remainder of the cut. Velocity control should be extended as far as inexpensive flexible ditch linings will permit. Consideration should also be given to providing positive outlets for underdrains and providing access to longitudinal sewer systems when locating ditch catch basins.

1102.3.6 Arbitrary Maximum Catch Basin Spacing

Catch basins are required at the low point of all sags and the earth dike noted in Section 1102.3.5 shall be omitted. The maximum distance between catch basins in depressed medians in fill sections shall be as follows:

Depressed Median Catch Basin Spacing (Fill Sections)Median Width (ft) Desirable Spacing (ft) Maximum Spacing (ft)

84 1250 150060 1000 125040 800 1000

Where underdrains are utilized, catch basins shall be provided at a maximum spacing of 1000 feet (500 feet with free draining base) to provide a positive outlet for underdrains.

1102.4 Ditch Design Criteria - Design Traffic of 2000 ADT or Less

1102.4.1 Design Frequency

A 5-year frequency storm shall be used to determine the depth of flow, and a 2-year frequency to determine the shear stress of flow and width of ditch lining, where needed. The depth of flow shall be limited to an elevation 9 inches below the edge of pavement for the design discharge. The depth of flow in toe of slope ditches shall be further limited such that the design year discharge does not overtop the ditch bank. The minimum width of lining shall be in accordance with Section 1102.3.1.

1102.4.2 Shear Stress Protection

Shear stress protection shall be in accordance with 1102.3.2 except that a 2-year frequency event shall be used.

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1102.4.3 Roughness

The roughness used for the hydraulic analysis shall be based on the Manning's Roughness Coefficient values shown in Table 1102-2.

1102.4.4 Catch Basin Types

Standard No. 5 Catch Basins, No. 2-2-A Catch Basin (within their safety limitations as discussed in Section 1102.3.4(D)) and No. 2-2-B Catch Basins should be considered for the lower ADT highways. Standard No. 4 Catch Basins should be used where additional capacity is required.

1102.5 Design Aids for Ditch Flow Analysis

1102.5.1 Earth Channel Charts

Standard radius roadside ditch charts have been prepared, based on the Manning’s equation, to facilitate the hydraulic analysis of ditch flow and are included in the Drainage Design Aids. Some of the more commonly used trapezoidal channel charts are also included.

Other trapezoidal channel charts (with 2:1 - 2:1 side slopes and bottom widths varying from 2 feet to 20 feet are available in the Federal Highway Administration publication referenced in section 1102.2.2.

All earth channel charts have been prepared using a Manning's Coefficient of Roughness of 0.03, which is recommended for a seed lining (Construction and Material Specifications Item 659). Qn and Vn scales have been included on all channel charts so that the channel flow may be analyzed for any value of “n” depending on the roughness of the channel or lining.

1102.5.2 Rectangular Channel Charts

Vertical side channel charts that can be used to analyze the open channel flow in box culverts are included in the Federal Highway Administration publication “Design Charts for Open Channel flow,” previously referred to.

1103 Pavement Drainage

1103.1 General

When curbs are provided at the edge of pavement or paved shoulder, (primarily in urban areas), it is necessary to determine the proper type of pavement inlet (or catch basin) to control the spread of water and depth of flow on the pavement. Present day geometric design has resulted in relatively flat transverse and longitudinal pavement slopes. These slopes require more pavement inlets (or catch basins) and consequently result in an appreciable increase in the drainage cost. To alleviate the above, where curb is permissible, standard curb and gutter should be used adjacent to the pavement. On normal section multi-lane highways where three (3) or more lanes are sloped in the same direction, it is desirable to counter the resulting increase in flow depth by increasing the cross slope of the outermost lanes. The two (2) lanes adjacent to the crown line should be pitched at the normal slope of 1.6 percent, and successive lane pairs or portions thereof outward, should be increased by 0.4 percent. Refer to Location and Design - Volume 1, Roadway design for additional geometric design criteria.

If paved shoulders are provided, the drainage cost will be decreased appreciably due to the large volume of flow that can be carried on the pavement shoulder without exceeding the allowable depth of 1 inch below the top of curb or a maximum of 5 inches; a maximum depth of 6 inches is permissible where a barrier shape is provided adjacent to the pavement.

Furnish a drainage design that will reduce the need for bridge scuppers by intercepting the flow prior to the bridge.

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A pavement drainage computation sheet similar to that provided in the Appendix shall be used to perform or summarize necessary computations.

Additional information concerning pavement drainage can be obtained from the Federal Highway Administration Hydraulic Engineering Circular No. 22, "Urban Drainage Design Manual."

1103.2 Design Frequency

Pavement inlets (or catch basins) shall be spaced to limit the spread of flow on the traveled lane (considered to be 12 feet wide) as shown in Table 1103-1. The allowable spread may be increased slightly for streets carrying predominantly local traffic and with design speeds less than 45 mph. Design shall be based upon the following frequencies:

Facility Design (years)

Freeways 10 High volume highways (Over 6000 ADT Rural or 9000 ADT Urban) 5

All other Highways 2

For underpasses or other depressed roadways where ponded water can be removed only through the storm sewer system, the spread shall be checked for a 50-year storm for Freeways and high volume highways as defined above, and for a 25-year storm for other multiple lane highways. Typically, this criteria does not apply to 2-lane facilities. Contact OHE if encountered. The ponding will be permitted to cover all but one through lane of a multiple lane pavement. The depth of flow at the curb shall not exceed 1 inch below the top of the curb for the design discharge regardless of the type of highway. A maximum depth of 6 inches is permissible where a barrier shape is provided adjacent to the pavement.

Table 1103-1

FacilityAllowable Pavement

Spread* (ft) Freeways 0 High Volume Highways (Over 6000 ADT Rural or 9000 ADT Urban)

≥ 45 mph 4< 45mph 2 lanes 6

≥4 lanes 8 All other Highways

2 lanes 6≥4 lanes 8

*Pavement spread applies to the through lane only

1103.3 Estimating Design Discharge

Runoff contributing to curbed pavements shall be estimated by the rational method, as explained in Sections 1101.2.2, 1101.2.3 and 1101.2.4.

The time of concentration “tc” shall be the actual time of concentration calculated according to Section 1101.2.2 with an absolute minimum time of 10 minutes.

In urban areas, where justifiable (e.g. contributing drainage area would be difficult to determine), the “strip method” may be used to determine contributing drainage areas. The strip method assumes a contributing drainage area of 150 feet taken on each side of the roadway centerline.

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1103.4 Capacity of Pavement Gutters

A pavement gutter has a right triangular shape, with the curb forming the vertical leg and the straight pavement slope, the gutter plate of a curb and gutter, or a paved shoulder forming the hypotenuse. A standard curb and gutter adjacent to a straight pavement slope, or paved shoulder, forms a composite gutter section which complicates the flow analysis. In most cases, the top width of the water surface in a pavement gutter far exceeds the height of the curb. The hydraulic radius does not accurately describe the gutter cross section in this situation, thereby requiring a modification to the Manning’s equation to analyze the gutter flow. The accepted modification results in the following equation:

𝑄 = 0.56𝑍𝑆1/2𝑑8/3

𝑛

Where:Q = Discharge in cubic feet per secondZ = Reciprocal of the pavement cross

slopen = Manning’s Coefficient of Roughness(Table 1102-2)

s = Longitudinal pavement sloped = Depth of flow in gutter section at

curb in feet

Figure 1103-1 provides a graphical solution for the above equation and its use is comparatively simple for straight transverse pavement slopes. However, the use of the Nomograph to determine depth of flow at the curb and resulting spread on the pavement for composite sections is much more involved.

1103.5 Pavement Flow Charts

Charts have been prepared for the more commonly used curbed pavement typical sections, and they are included in the Drainage Design Aids. The charts are particularly helpful for determining the flow for composite pavement sections where the spread can be read directly from the appropriate Pavement Flow Chart.

To use the charts, enter with a predetermined design discharge (total flow) Qt in the gutter in cubic feet per second and proceed vertically to intersect the longitudinal gutter slope line. At that intersection, read the spread in feet shown on the diagonal spread lines.

The spread of flow will generally control the pavement inlet or catch basin spacing, where the transverse and longitudinal slope of the pavement is relatively flat. The above is prevalent in long flat sag vertical curves, where a flanking inlet (or catch basin) should arbitrarily be provided on both sides of the low point in a pavement sag. This is particularly so for Freeways. Three inlets or catch basins in a sag can be justified only on the basis of need for other highway classifications. Usually a Standard 6 foot pavement inlet or No. 3A catch basin will be adequate, and they should be placed where the grade elevation is approximately 0.20 feet higher than at the low point. Furnish a CB-No. 3 at the sump.

Inlets or catch basins should arbitrarily be placed upstream of all intersections, bridges and pedestrian ramps. When justified, inlets (or catch basins) should be located a minimum of 10 feet off drive aprons, intersection return radii, pedestrian ramps or curb termini.

1103.6 Bypass Charts for Continuous Pavement Grades

Bypass charts are included for the standard pavement inlets and catch basins in the Drainage Design Aids. Bypass for a given structure can be read directly from the chart (At the intersection of the spread, determined in Section 1103.5, and the longitudinal gutter slope, read the bypass flow Qb on the abscissa). Experience has proven that, for greater efficiency, inlets should be sized to bypass a minimum of 10% to 15% of the design discharge. This criterion should be used to determine the type or length of inlet to be

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used in a given location. It is not intended to establish the required spacing. The most efficient design maintains the allowable spread on continuous grades and at the sag.

The bypass for a catch basin or inlet should be added to the total flow in the adjacent downstream gutter section.

1103.6.1 Curb Opening Inlets

The flow bypassing a standard curb opening inlet, for pavement transverse slopes or combination of slopes differing from the charts included in the Drainage Design Aids, may be obtained from Figure 1103-2. The use of curb opening inlets should be avoided where bicycle traffic is expected.

1103.6.2 Grate or Combination Grate and Curb Opening Inlet

The standard pavement catch basin in this category is considered to intercept all the flow over the grate when used on continuous grades. A portion of the flow outside of the edge of the grate will also be intercepted, the amount varying with the depth of flow “y” along the edge of the grate. The depth “y” can be determined from Figure 1103-1, and the resulting flow spilling over the edge of the grate from Figure 1103-2, using a ½ inch local depression for straight transverse pavement slopes, or no local depression for a composite gutter section. The local depression mentioned above is at the front face of the grate closest to the centerline of the roadway. This depression is not the same depression identified in the in the standard construction drawings. The curb opening of a combination catch basin on a continuous grade will admit some flow, particularly if there is a partial clogging of the grate; however, the additional capacity should be considered as a factor of safety only.

1103.7 Grate Catch Basins and Curb Opening Inlets in Pavement Sags

The spread determined from the pavement flow charts need not be checked any closer than 25 to 50 feet on either side of the sag, well beyond the limits of the local depression. The spread in the sag should be determined from the depth of flow at the edge of grate using Figure 1103-3 and should include the total flow (contributions from each side of the sag vertical curve) reaching the inlet or catch basin.

Standard No. 3 catch basins should be used in pavement sags. The capacity of the grates to admit flow is based on the depth of ponding around the grates. The capacity of the grates shown in Figure 1103-3 is based on weir flow over the edge of the grate, up to a depth of 0.4 feet. For greater depths, the total area of grate opening is considered, with no deduction made for possible clogging. When evaluating the spread in a depressed sag for a 25-year or 50-year event, the capacity of the window shall be considered. This capacity may be obtained from Figure 1103-4. The curb opening capacity should be added to the grate capacity for submerged conditions.

Where the low point of a sag vertical curve occurs in a drive, a No. 6 catch basin should be provided at the low point with flanking No. 3A catch basins as per Section 1103.5.

No. 6 catch basins may be used along curbed roadways and medians provided that the grate capacity is not exceeded.

1103.8 Bridge Deck Drainage

Furnish a minimum longitudinal grade of 0.3% for the bridge deck surface when using concrete parapets.

Minimize or eliminate the number of scuppers. Calculate the allowable spread of flow using procedures described in Section 1103. On flatter longitudinal slopes, scuppers will intercept a portion of flow slightly wider than the width of the scupper (side flow), while on steeper longitudinal slopes, a portion of the flow in the gutter section occupied by the scupper (frontal flow) may splash over the grate. Assuming side capture and splash over are negligible, the frontal flow ratio is considered equal to the inlet efficiency. The fraction of flow captured by the scupper can be determined by the following equation:

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𝐸 = 1 ‒ (1 ‒𝑊𝑇 )2.67

Where:E = Scupper efficiencyW = Width of scupper in feetT = Total width of spread in feet

The scupper bypass flow can be determined by the following equation:

𝑄𝑏 = 𝑄(1 ‒ 𝐸)

Where:Qb = Bypass discharge in cubic feet per secondQ = Total discharge in gutter in cubic feet per secondE = Scupper efficiency

A spreadsheet to determine scupper bypass flow has been created and can be found on the Office of Hydraulic Engineering website at the following location:http://www.dot.state.oh.us/Divisions/Engineering/Hydraulics/Additionsl%20Resources/Pages/default.aspx

Use a computation sheet, similar to that provided in the link above to perform scupper calculations.

Information concerning bridge deck drainage can be obtained from the Federal Highway Administration Hydraulic Engineering Circular No. 21, “Design of Bridge Deck Drainage.” Software utilizing methods outlined in HEC-21 are also acceptable for scupper analysis.

Locate scuppers inside the fascia beam unless the parapet and beam spacing make this impractical. Furnish scuppers with vertical drops or nearly vertical drops when feasible. If a scupper pan is required, angle the pan as steeply as possible.

Furnish an uncollected / free fall as per SCD GSD-1-96. Substitute heavy duty cast iron deck drains as currently manufactured by Neenah or equal, when SCD GSD-1-96 will not physically fit due to parapet, beam line and the deck overhang. If a drainage collection system is required ensure that it meets the following:

A. System is sloped greater than or equal to 15 degrees

B. Bends have a minimum radius of 18 inches

C. Bends have angles greater than 90 degrees

D. Cleanout plugs are easily and safely accessible

E. Furnish drainage collection when using finger joints or sliding plates. Provide a neoprene drainage trough under finger joints. Show the necessary deck drainage outlet locations on the preliminary structure site plan. Include this information in the Structure Type Study (BDM 201).

Place scuppers with drainage collection systems as close as feasible to the substructure unit which drains them. Place uncollected / free fall scupper downspouts as far away from any part of the structure as possible.

See Section 1113 for bridge bypass flow.

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1103.9 Slotted Drains and Trench Drains

Slotted and Trench drains are used to capture sheet flow in areas where curb is not present to collect and direct flow to a catch basin such as a gore area.

Trench drains and slotted drain systems are susceptible to clogging and are not recommended where significant sediment or debris load is present. Locate trench drains and slotted drains longitudinally with the edge of pavement. Ensure the drain and any surrounding concrete is outside of the travelled way. Locate trench drains at the end of commercial drives to intercept large flows before entering into the travelled way.

Outlet the drains to a Catch Basin No.6 to aid in cleanout.

Furnish a Catch Basin No. 6 at minimum 100 ft. intervals to facilitate cleanout for slotted drains. Refer to SCD DM-1.3 for slotted drain details. Furnish Plan Note D120 when utilizing slotted drain.

Specify supplemental specification 839 and 939 when using trench drain.

1104 Storm Sewers

1104.1 General

Storm sewer systems are designed to collect and carry storm water runoff from the first pavement or ditch inlet, or catch basin to the predetermined outlet. (Further reference to inlets infers either inlets or catch basins). Long cut sections often result in the need for longitudinal trunk sewers to accept the flow from a series of inlets. The proper location of a sewer outlet is important. Existing drainage patterns should be perpetuated insofar as practicable. Careful consideration should be given to the possibility of actionable damage for the diversion of substantial volumes of flow. Long fill sections requiring median or pavement drains may best be served by transverse sewers that outlet independently at the toe of fill ditch.

Storm sewer systems shall be sized to convey the current flow from areas naturally contributing to the highway or from intercepting existing storm sewers. Adherence to Local drainage criteria and standards is not applicable for ODOT owned and maintained drainage assets. Storm sewer systems may be oversized at the request of a local government entity to convey flow from areas beyond those considered highway responsibility or increased flows from anticipated development with the approval of the OHE. The additional cost to construct the increased sized storm sewer system will be the responsibility of the local government. The proration of project funds and local government funds will be determined from estimated construction costs. The project funding participation will be determined as a percentage of the total cost of the affected plan items. The percentage will be computed by dividing the estimated cost to construct a highway responsibility system only by the estimated cost to construct the oversized system. The affected plan items and participation percentage will be noted in the plan general summary.

Type B conduit shall be specified for storm sewers under pavement, paved shoulders and commercial or industrial drives and Type C conduits for storm sewers beyond those limits. However, the type of conduit shall not be changed for a short run of conduit which would ordinarily require a change in conduit type.

As an example of the above, Type B should be used for a transverse conduit that is required to drain an earth median catch basin in an embankment section under the pavement to a point approximately 10 feet from the embankment slope. A concrete collar, as per Standard Construction Drawing DM-1.1, should be provided to connect the Type B and a Type F Conduit, located back of, and parallel to, the embankment slope. Type F conduit, 707.05 Type C or 707.21 shall be provided for the pipe specials required to negotiate the bend at the top and bottom of the embankment. A detail is provided in Figure 1104-1.

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The Construction and Material Specifications stipulate the permissible pipe shapes and materials. Storm sewer designs will be based on round pipe, and the choice of the permissible material types for the conduit specified will be the contractor’s option. When extending existing Type B & C conduits, the extensions will match the existing material in kind. The length of conduit to be paid for will be the actual number of linear feet, measured from center-to-center of appurtenant small structures. No deduction will be made for catch basins, inlets or manholes that are 6 feet or less across, measured in the direction of flow. Conduits placed on slopes steeper than 3:1 or with beveled or skewed ends are measured along the invert.

Changes to grade may occur at existing manholes due to proposed work. With a decrease in grade of not more than 6 inches or an increase in grade of not more than 12 inches the existing structure may be Adjusted to Grade. Where grade elevation changes are greater, the existing structure should be Reconstructed to Grade.

For examples of storm sewer detail sheets, reference Sample Plan Sheets 1312-4 and 1312-5, maintained by the Office of CADD and Mapping. These provide a useful resource for preparation of hydraulic plans in terms of layout and content.

1104.2 Design Considerations

1104.2.1 Storm Sewer Depth

Keep a storm sewer system as shallow as possible, consistent with the following controls:

A. Provide a minimum cover of 9 inches from the top of a rigid pipe to the bottom of the pavement subbase; however, in no installation shall the distance from the top of the rigid pipe to the pavement surface be less than 15 inches. Provide a minimum cover of at least 18 inches for pipe not under pavement.

B. Provide a minimum cover of 12” from the top of flexible pipe to the bottom of the pavement subbase; however, in no installation shall the distance from the top of the flexible pipe to the pavement or ground surface be less than 24”.

C. Provide a minimum cover of 4” from the top of extra strength pipe to the bottom of the pavement subbase; however, in no installation shall the distance from the top of the extra strength pipe to the pavement surface be less than 10 inches. Provide a minimum cover of at least 4” if not under the pavement. If the minimum cover cannot be provided, check with OHE to determine the required extra strength.

D. Provide a sufficient depth to permit the use of precast inlets, catch basins and manholes. Refer to the Standard Construction Drawings for this information. In no installation shall the top of pipe be in the precast top section of the inlet, catch basin or manhole. See Table 1104-1 for maximum storm sewer pipe thicknesses.

E. Provide a sufficient depth to avoid interference with existing utilities such as sanitary sewers, the grade of which cannot be changed.

F. Provide a sufficient depth to create a positive outlet for underdrains. It is desirable to maintain the underdrain outlet 12 inches above the flow line of the outlet structure with 6 inches as a minimum.

G. Provide sufficient slope to maintain a minimum velocity of 3 feet per second, for self-cleansing. This velocity is calculated using the “just full” Manning’s Equation.

H. Match the crown of a smaller upstream pipe in a longitudinal trunk sewer to the crown of the adjacent

downstream pipe.

I. Minimum invert elevation = finished grade – minimum cover – wall thickness (per Table 1104-1) – inside diameter

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Table 1104-1Dimensions of Wall Thickness for Storm Sewer

Inside Diameter (inch)

Wall Thickness (inch)

Outside Diameter

(inch)12 2 1615 2-1/4 19-1/218 2-1/2 2321 2-3/4 26-1/224 3 3027 3-1/4 33-1/230 3-1/2 3736 4 4442 4-1/2 5148 5 5854 5-1/2 6560 6 7266 6-1/2 7972 7 86

Where proposed highway storm sewers or ditches will interfere with existing private drains carrying treated or untreated sanitary flow, submit the names and addresses of the affected property owners to the District Deputy Director. Obtain the above information well in advance of the Field Drainage Review so the appropriate provisions of Directive No. 22-A can be followed (found in the Appendix A).

1104.2.2 Storm Sewer Access

Most standard catch basins and pavement inlets will provide sufficient access to small shallow sewers. Catch basin or pavement inlets can be used to negotiate changes in sewer sizes or minor horizontal or vertical direction changes within the size limitation of the structure, but more pronounced changes may require manholes.

It may be necessary, or desirable to locate longitudinal trunk sewers away from the curb to provide for a utility strip between the curb and the sidewalk and to avoid a conflict with the underdrain system. This will require properly spaced manholes in the sewer line. Small sewers (under 36 inches in diameter) located under or near the edge of pavement, should be accessible at intervals not to exceed 300 feet. For sewers sized 36 to 60 inches manholes should be spaced every 500 feet maximum. Manholes should be provided every 750 to 1000 feet maximum for larger sewers.

1104.2.3 Rock Excavation for Storm Sewer

If it is known that bedrock will be encountered in the excavation for storm sewer installation, relocate the storm sewer. If bedrock cannot be avoided, separate the quantities of the storm sewer in rock and include “611, As Per Plan” in the plans.

1104.3 Layout Procedure

1104.3.1 Plan

A print of the plan sheets involved should be used to spot catch basins and inlets that are required to drain the project and satisfy maximum allowable depth and/or spread of flow. A strip map showing the delineated drainage area and topography is required. The map will provide the designer with a means of determining the drainage area and the weighted coefficient of runoff for the individual areas contributing flow to the required storm sewer system.

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1104.3.2 Profile

A profile of the existing and proposed pavement or ground line over the proposed sewer location should be plotted. On the same profile, plot the locations of catch basins, inlets and manholes, along with a tentative storm sewer system.

1104.4 Storm Sewer Design Criteria

1104.4.1 Design Frequency

All storm sewers shall be sized to flow just full (i.e. depth of flow for maximum discharge) for a 10-year frequency storm. The size is determined by working downstream from the first sewer run. It will be acceptable to use a discharge of a more frequent occurrence if consistent with local criteria (depending upon the design ADT of the roadway) or to avoid extensive replacement of an existing downstream drainage system.

1104.4.2 Hydraulic Grade Line

Starting at the storm sewer system outlet and working upstream, the elevation of the hydraulic grade line at the upper end of each sewer run should be determined using a 25-year frequency. It will be acceptable to use a discharge of a more frequent occurrence if consistent with local criteria (depending upon the design ADT of the roadway) or to avoid extensive replacement of an existing downstream drainage system. Ordinarily, the hydraulic grade line will be above the top of the pipe, causing the system to operate under pressure. If, however, any run in the system does not flow full, (pipe slope steeper than the friction slope) the hydraulic grade line will follow the friction slope until it reaches the normal depth of flow in the steep run. From that point, the hydraulic grade line will coincide with the normal depth of flow until it reaches a run flatter than the friction slope for that run.

The starting elevation for the hydraulic grade line determination should be the higher of either: the downstream tail water channel water surface elevation or (dc+D)/2 at the system outlet. Section 1105.6.1

The intensity “i” in the rational equation Q=CiA [Q=CiA/360] used to determine the check discharge (25-year frequency) shall be the same for all sewer runs as that calculated for the last, or downstream run, in a continuous sewer system. The hydraulic grade line shall not exceed the following for any roadway with greater than 2000 ADT:

A. 12 inches below the edge of pavement for sections without curb.

B. The elevation of a curb opening inlet or grate elevation of a pavement catch basin.

Consideration shall be given to a reduction in the design frequency and to more liberal hydraulic grade line controls for less important highways than those noted above.

The check discharge, to determine the elevation of the hydraulic grade line for highways having depressed sags that must be drained by storm sewers, shall be based on a 50-year frequency. One directional lane of a multiple lane highway or one-half of a lane on a 2-lane highway should be passable when the sewer system is discharging the 50-year storm.Storm sewers for all highways shall satisfy a 50-year check to preclude flooding of buildings or extensive flooding of private property.

If the hydraulic grade line exceeds the limits noted above, the controlling sewer size shall be increased. (These criteria are not intended to lower existing high water elevations)

1104.4.3 Coefficient of Runoff

The weighted coefficient of runoff shall be determined as explained in Section 1101.2.3

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1104.4.4 Time of Concentration

The time shall be determined as explained in Section 1101.2.2. A minimum time of concentration of 15 minutes to the first ditch catch basin and 10 minutes to the first pavement inlet shall be used. The actual calculated time of concentration shall be used when values greater than these minimums occur.

1104.4.5 Pipe Roughness Coefficient

A Manning’s “n” of 0.015 shall be used for sewers 60 inches in diameter and under, and 0.013 for larger sewers. The basic “n” value for smooth pipe, concrete, vitrified clay, bituminous lined corrugated steel or thermoplastic is 0.012. The increased values are recommended for sewers to compensate for minor head losses incurred at catch basins, inlets and manholes located in a storm sewer system.

1104.4.6 Minimum Storm Sewer Pipe Size

A minimum pipe diameter of 15 inches shall be used for Freeways and Freeway ramps (Where an existing storm sewer is to remain in service, it is not necessary to replace, hydraulically adequate pipes to meet this criterion) and 12 inches for other highways.

1104.4.7 Maximum Storm Sewer Slope

For storm sewers designated as Type B or Type C, the maximum slope is 25%. For storm sewers with slopes that exceed 25%, designate as Type F. 1104.5 Hydraulic Design Procedure

With the layout suggested in Section 1104.3, start with the upper catch basin or inlet and determine the value of CA for the contributing flow (CA is the product of the weighted coefficient of runoff and the drainage area). Next, determine the time of concentration for the first area and the corresponding rainfall intensity “i” from the proper curve shown on Figure 1101-2. The design discharge “Q” to use to determine the required size of the first sewer from MH No. 1 to MH No. 2 is the product of Ca x i [0.0028CA x i]. At manhole No. 2, determine the value of CA for the additional area contributing at that point and add to the CA for MH No. 1.

Compute the time of flow in the storm sewer from MH No.1 to MH No. 2 in minutes and add to the time of concentration at MH No. 1. Check the time of concentration for the area contributing to MH No. 2, and use the larger of the two as the duration for the new value of rainfall intensity for computing the design flow from MH No. 2 to MH No. 3.

It is obvious that the process is quite involved, and a storm sewer computation sheet similar to that provided in the Appendix shall be used to tabulate the required information. The calculations for lateral connections to the longitudinal trunk sewer should be tabulated separately from the trunk sewer calculations. Software developed by ODOT (CDSS) is available online and can be used for these calculations. StormCAD may also be used for these calculations. Other software packages may be utilized with approval from OHE. 1104.6 Combined Sanitary Sewer Separation

When the Combined Sanitary Authority is under court order to address frequent overflow of the sanitary system due to storm sewer impacts, every effort should be made to furnish an exclusive outfall for the storm sewer when feasible. Coordination with the Local is required. While adherence to Local drainage standards is not applicable for ODOT owned and maintained drainage assets it may be possible for the Department to incorporate the needs of the local entity subject to review and approval of OHE.The Department will fund storm sewer conduit and drainage structures to ensure positive drainage of the roadway when a separation is feasible. Conduit and structures required for sanitary sewer will be funded by the Local. All conduit located outside of the Department owned right-of-way will be funded by the Local. Conduit will be furnished for the most feasible and direct route of storm or sanitary sewer as determined by the Department.

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1105 Roadway Culverts

1105.1 General

A culvert generally carries a natural stream under the highway embankment. The culvert horizontal and vertical alignment should approximate that of the natural channel and thereby minimize stream impacts and the need for channel relocations. Ensure the upstream invert is not below the natural channel unless the culvert has depressed inverts, a paved depressed approach apron, or an improved inlet.

Optimum culvert design (i.e., best hydraulic performance and least environmental impacts) occurs when the roadway alignment is normal to the flow in the channel and is located on a relatively straight and stable section of the channel. Roadway alignment needs to be considered early in the design process to provide optimum culvert design. The proposed roadway should avoid stream confluences. Culverts should not be placed on skews in excess of 45º or as further limited in Section 1008.

Check the design with a single-cell round pipe as a first choice. In cases where required cover or discharge precludes a round pipe, select a shape that reduces the vertical requirements while maintaining the hydraulic capacity. Check the design with the following shapes in order of minimum cost to increasing cost: single-cell elliptical concrete, metal pipe-arch, prefabricated box culvert or three-sided structure. For justification of multiple cell culverts, see Section 1105.7.2.

In general, maintain the existing upstream and downstream hydraulics when replacing an existing culvert. In cases where these parameters must be modified, evaluate any upstream and downstream impacts. Culvert location should perpetuate existing drainage patterns (depth of flow, direction of flow, overbank flow) to the maximum extent practicable. Diversion of substantial volumes of flow requires regulatory consideration and possible actionable damage.

Label the depth or elevation of the Ordinary High Water Mark (OHWM) for jurisdictional waterways on the Culvert Detail Sheet for all culverts. The depth is measured from the centerline of the waterway. The OHWM is calculated per Section1105.6.13 or determined by the Office of Environmental Services.

For examples of culvert detail sheets, reference Sample Plan Sheets Section 1312 – Drainage Details, maintained by the Office of CADD and Mapping. These provide a useful resource for preparation of hydraulic plans in terms of layout and content.

1105.2 Stream Protection

Stream protection practices are provided to improve stream channel stability. Erosion of the stream channel can migrate upstream and downstream without proper protection at the structure.

Provide stream protection practices (water quantity treatment) for all culvert projects when the project earth disturbing acreage exceeds the thresholds for post-construction Best Management Practices (BMP) outlined in Section 1115.2. Exceptions for providing stream protection to meet post-construction BMP requirements are noted in Section 1115.3. In addition to post-construction BMP requirements, waterway permit conditions and site specific features may require the use of practices described throughout this Section.

Stream protection for culvert projects is provided through the use of the following practices and is only applicable to grade control within Waters of the United States:

Bankfull discharge design Depressed culvert inverts Paved depressed approach aprons Flood plain culverts

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Only the project areas that drain to a grade control structure will receive treatment credit. If the treatment provided by a grade control structure does not meet the required percentage of treatment, provide treatment in the areas not draining to the grade control structure for the remaining amount required.

For existing culvert replacements, inspect the channel for erosion that has caused undercutting or downcutting at the inlet of the culvert. At locations with evidence of undercutting or downcutting, provide a concrete apron according to Section 1106.3 at the inlet and outlet of the culvert to restore previous stream elevations and provide stream protection.

The use of each stream protection practice is limited based on project specific conditions.

If the stream protection practices listed above are not applicable or available based on project type, site constraints or limitations, the project is not exempt from providing stream protection BMP. Other methods of stream protection must be used.

In addition to the stream protection practices described within this Section, the following post-construction storm water BMP may be utilized within available right-of-way or right-of-way being obtained for roadway purposes to provide stream protection and treat storm water runoff when the project earth disturbed area is equal to or exceeds one acre:

Extended Detention (See Section 1117.3) Retention Basin (See Section 1117.4) Bioretention Cell (See Section 1117.5) Infiltration Methods (See Section 1117.6) Constructed Wetlands (See Section 1117.7)

See Sections 1115 through 1117 for further information concerning post-construction storm water BMPs.

1105.2.1 Bankfull Discharge Design

Culverts utilizing Bankfull Discharge Design are required to convey the bankfull discharge with minimum change in the stream energy for the adjoining channel sections when compared to the existing conditions.

The proposed culvert will minimize the impact to the stream channel by closely matching the existing depth of flow with the proposed depth of flow for the bankfull discharge.

Provide Bankfull Discharge Design for all culverts conveying streams with the following exceptions:

The culvert is a replacement structure (permitted under the Regional General Permit for ODOT or a Nationwide Permit #3 - Maintenance).

The culvert rise is 30" or less. The culvert is located on bedrock. The culvert slope exceeds 1%.

If multiple cell culverts are provided, ensure only one culvert conveys the bankfull discharge. Place the invert of additional culverts at the water surface elevation generated by the bankfull discharge. Use the following design steps when performing a bankfull discharge design:

1. Determine the bankfull discharge using USGS report 2005-5153, “Bankfull Characteristics of Ohio Streams and Their Relation To Peak Streamflows”. Use the regression equation that utilizes USGS map-based explanatory variables. The report can be obtained from USGS at:http://pubs.usgs.gov/sir/2005/5153/

2. Determine the culvert size from traditional culvert hydraulic design.

3. Depress the culvert invert according to Section 1105.2.2.

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4. Determine the depth of flow for the pre-developed channel using the bankfull discharge at locations 25 feet before the culvert inlet, at the culvert, and 25 feet beyond the culvert outlet. Determine the depth of flow for the bankfull discharge based on field-obtained stream cross-sections and the use of a standard step-backwater water-surface profile model such as HEC-RAS or the use of other software capable of calculating depth of flow based on Manning’s equation.

5. Determine the depth of flow for the post-developed channel using the bankfull discharge at the same locations identified in Step 4 through use of a standard step-backwater water-surface profile model such as HEC-RAS or the use of other software capable of calculating depth of flow based on Manning’s equation. The cross section at the culvert will reflect the geometry of the culvert.

6. Compare the depth of flow from step 4 to step 5. Adjust the culvert dimensions until the post-developed condition flow depth (Step 5) is approximately equal to the pre-developed flow depth (Step 4).

7. Add flood plain culverts if required (see section 1105.2.4).

8. Determine if the culvert meets the required hydraulic design controls. Upsize the culvert as required

1105.2.2 Depressed Culvert Inverts

Provide depressed inverts for all culverts designed to convey the Bankfull Discharge Design.

Depressed culvert inverts will produce a natural channel bottom within the culvert. The natural channel bottom provides a substrate for passage of migratory species.

The depressed culvert will fill naturally, such that the channel bed in the culvert will be continuous with the adjacent channel sections.

Verify that the culvert meets the required hydraulic design controls realizing that the portion of the culvert depressed will eventually fill with natural substrates. Upsize the culvert as required.

End treatments for culverts with depressed inverts consist of Item 601 Riprap, 6” Reinforced Concrete Slab with a cutoff wall on both inlet and outlet ends. See standard construction drawing DM-1.1 for details.

Depress the culvert invert according to Table 1105-1: Table 1105-1

Type A Conduit Invert DepressionPipe Diameter or

Rise (inch)Depression

(inch)< 36 None

36 - 60 666 - 120 12

126 - 180 18186 - 252 24

> 252 30

Modifications to the standard headwalls are not necessary for the depression depths noted above.

Depressed inverts are not required for precast reinforced concrete three-sided flat-topped culverts with a natural channel bottom.

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1105.2.3 Paved Depressed Approach Aprons

In many cases, the hydraulic operation of a culvert can be improved by depressing the flowline at the entrance below the channel flowline. The drop-down will alleviate a minimum cover condition, provide for additional headwater depth, and decrease the culvert outlet velocity by reducing the culvert slope.

The abrupt change in natural channel slope is effected with a short length of concrete paving to prevent downcutting of the stream. The dimensions of the slab are site specific. However, for ease of construction, a 2:1 downslope should be used as the maximum descending slope. A 3-foot length of paving should be provided along the natural channel slope prior to the drop-down. A cut-off wall must be provided at the upstream end.

In general, limit drop-down entrances to 4 feet, or one pipe diameter or rise, whichever is greater.

The Federal Highway Administration has conducted extensive research and studies of paved depressed approach aprons, and recommended design procedures are included in Hydraulic Design Series No. 5, "Hydraulic Design of Highway Culverts."

1105.2.4 Flood Plain Culverts

For all new bankfull culvert installations, consider the use of flood plain culverts. In wide flood plains, the installation of a new single culvert constricts the flow of water at the entrance section. The concentrated outflow from the culvert can initiate downstream channel degradation. Flood plain culverts can be used to minimize the effects of this new concentrated discharge by spreading the discharge throughout the flood plain or flood prone area on the outlet side of the culvert.

Provide flood plain culverts when the flood plain width is greater than two (2) times the width produced by the bankfull discharge design.

Flood plain culverts are installed adjacent to the single culvert. Place flood plain culvert inverts at the water surface elevation that is generated by the bankfull discharge design. Locate the flood plain culverts within the flood plain at a location well beyond the single culvert. Furnish a minimum of two flood plain culverts. Figure 1102-2 illustrates the location of flood plain culverts with respect to the bankfull channel and flood plain.

Flood plain culverts are not hydraulically designed or accounted for in the hydraulic design of the single culvert. Use Figure 1002-1 (“other” column) to determine the required diameter. The line and grade of the culvert should approximate that of the natural flood plain.

1105.2.5 Energy Control Structures

Provide energy control structures for all culverts with an outlet velocity greater than five feet per second. The use of energy control structures does not constitute water quantity treatment for post-construction BMP purposes.

An energy control structure reduces the amount of erosive energy generated by a culvert. Use the following for an energy control structure:

Broken-Back Culvert Rock Channel Protection Energy dissipator (Riprap Basin) Drop Structure

Provide an energy dissipator when the outlet velocity exceeds the values shown in Figure 1107-1. Energy dissipaters create a forced hydraulic jump within the structure or immediately downstream of the structure, thus reducing the flow velocity. FHWA Hydraulic Engineering Circular No. 14 provides design guidance and procedures for various energy dissipators. A riprap basin is the most cost effective energy dissipator.

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Contact OHE prior to using an energy dissipator.

1105.3 Types of Culvert Flow

Laboratory tests sponsored by the FHWA have established two general types of culvert flow: (1) flow with inlet control, or (2) flow with outlet control. Nomographs have been prepared for use in the determination of culvert headwater for the appropriate control.

Under inlet control, the headwater “HWI” is directly related to the cross-sectional area of the culvert barrel and the inlet geometry. Under outlet control, the headwater “HWO” is further influenced by tailwater depth in the outlet channel and the slope, length and roughness of the culvert barrel. As shown in Figure 1105-3, culverts operate with a free water surface if the headwater is equal to or less than 1.2D, and with a submerged entrance if the headwater is greater than 1.2D, where D is the diameter or rise of the pipe.

1105.4 Design Procedure

1105.4.1 General

The design of a culvert involves a determination of the appropriate design and check discharges. The process begins with a delineation of the drainage area, in acres [hectares], on a suitable topographic map. The design discharge “Q” for most culvert drainage areas will be obtained by procedures described in Section 1003.1.2 of this manual. The Rational method should be used to obtain the discharge from small and other unusual drainage areas as noted in Section 1101.2.2

A representative cross-section of the embankment at the proposed culvert site, along with a profile of the natural stream or ground line, will be required to determine the approximate length and slope of the culvert.

1105.4.2 Hydraulic Analysis

The hydraulic analysis of a culvert, including a determination of the headwater depth and outlet velocity for the design discharge, is simplified by the use of Pipe Flow Charts and the headwater and head nomographs noted in Section 1105.4. The charts are included with the Drainage Design Aids, beginning with Figure 1100-200.

To preclude the need for a determination of the probable type of flow under which a culvert will operate for a given set of conditions, the headwater depths may be computed using the nomographs for both inlet and outlet control. The size of pipe is then selected by using the control giving the higher headwater limitation.

The relationship of the headwater to the diameter or height of the culvert “HW/D” is read directly from the inlet control nomograph and the HWI equals that value multiplied by D. HWO is computed by the equation HWO=H+ho - SoL.;/ The loss of head “H” is read from the flowing-full nomograph and the tailwater depth “ho”, is the greater of either the normal depth of flow in the outlet channel or the depth as flow passes through the outlet of the pipe, calculated as (dc+D)/2. D is the diameter or rise of the culvert and dc is the critical depth of flow which may be read from the critical depth curve shown on each Pipe Flow Chart.

The above procedure is reasonably accurate for the majority of culvert flow conditions. For culverts operating with outlet control (see Figure 1105-1, Class 1-A and 1-B), where the calculated headwater (using the appropriate nomograph) is less than 0.75D, a backwater analysis can be justified and is recommended.

A culvert analysis sheet similar to that provided in the Appendix shall be used to tabulate all the pertinent factors required to determine the controlling headwater for each culvert type being considered for a given location. The analysis sheet includes other information valuable to the reviewer and it is to be included with other supporting data for required review submissions.

Hydraulic analysis of culverts may also be performed utilizing the Federal Highway Administration Hydraulic Design Series No. 5, Hydraulic Design of Highway Culverts. Computer programs such as FHWA HY-8 or ODOT’s CDSS software package may be used. CDSS may be downloaded from the Hydraulics website.

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For replacement projects, an analysis of the existing structure shall be performed. Use the same analysis method when comparing the existing and proposed structures. For bridge replacements, the acceptable method of hydraulic analysis is HEC-RAS.

1105.5 Use of Nomographs

1105.5.1 Outlet Control

To determine the loss of head “H” for a given concrete pipe culvert with a grove-end entrance and discharge “Q”, proceed as follows: By straight line, connect culvert size with ke=0.2 (length scale) and obtain a point on the turning line. Connect the turning line point with the computed discharge “Q” and read the head loss “H”. Follow the same procedure for a corrugated metal pipe except using ke=0.9 (length scale). The ke value for additional shapes can be found in the Federal Highway Administration publication referenced in Section 1105.3.1.

Should the roughness coefficient “n” of the proposed pipe differ from that shown on the chart, adjust the measured culvert length by the length factor given on Design Aid Figure 1100-247. For an example, see Drainage Design Aid Figure 1100-247.

The Federal Highway Administration publication referenced in Section 1105.3.1 offers nomographs for culvert shapes not available in the Drainage Design Aids. Their use is recommended for special culvert shapes.

1105.5.2 Inlet Control

To determine the headwater “HW” for a given discharge “Q”, size and type of culvert, proceed as follows using appropriate Figures 1100-245, 1100-246 (Drainage Design Aids). Use Figure 1100-245 for a round corrugated metal pipe culvert and Figure 1100-246 for a round smooth-lined pipe culvert. By a straight line, connect the culvert size with the discharge “Q”, extend a diagonal line to Scale (1) and thence by horizontal line to Scale (3). Based on a groove-end entrance and a Standard HW-2.1 headwall recommended for concrete pipe culverts, the HW/D relationship is obtained by an average of the (2) and (3) Scale values. Follow the same procedure for a corrugated metal pipe with a Standard HW-2.2 headwall, where HW/D is the average values read from Scales (1) and (3). Use Scale (2) for the HW/D relationship for concrete box culverts.

1105.6 Design Criteria

1105.6.1 Design Frequency

The design frequency shall be as stated in Section 1004.2It should be noted that a Flood Hazard Evaluation using a check discharge based on the 100-year flood frequency shall be made for all culverts as noted in Section 1005.2.1.

1105.6.2 Maximum Allowable Headwater

See Section 1006.

1105.6.3 Method Used to Estimate Storm Discharge

See Sections 1003 and 1101.

1105.6.4 Scale of Topographic Mapping Used to Delineate Contributing Drainage Areas

See Section 1101.1

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1105.6.5 Manning’s Roughness Coefficient “n”

The “n” values for corrugated metal pipe are given in Figure 1105-2. The “n” value for all smooth flow pipe is 0.012. Use a weighted Manning’s n for bankfull designed culverts or analyzing older culverts with sediment deposition.

1105.6.6 Entrance Loss Coefficient “ke”

See Table 1105-2 or Appendix D of Federal Highway Hydraulic Design Series No. 5, "Hydraulic Design of Roadway Culverts.

Table 1105-2Type A Conduit

Entrance Loss Coefficient ke

Type of Pipe Headwall TypeFull One-Half None

Concrete, Vitrified (thick wall) * 0.2 0.2 0.2

Corrugated Metal (thin wall) 0.25** 0.9 0.9

* groove end entrance** beveled entrance

Plastic conduits without a welded bell inlet will be designed as a corrugated metal conduit. Plastic conduits with a welded bell inlet will be designed as a concrete conduit. In both cases, the Manning’s “n” value for plastic is 0.012.

1105.6.7 Minimum Cover

See Section 1008

1105.6.8 Maximum Cover

See Section 1008

1105.6.9 Maximum Allowable Outlet Velocity

See Figure 1107-1

1105.6.10 Headwall Type

See Section 1106.2

1105.6.11 Contacts With County Engineer

Contact the County Engineer at the beginning of the design process to review the proposed location, both horizontal and vertical, in order to ascertain ditch cleanout grades. Use Form LD-33 (available in the Appendix) to document approval.

1105.6.12 Minimum Pipe Size

As specified in Section 1002.3.1

1105.6.13 Ordinary High Water Mark

Determine the elevation and lateral extents of the OHWM following the USACE RGL No. 05-05.

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1105.7 Special Considerations

The following are special conditions that will be encountered in the hydraulic design of culverts that warrant clarification. Apply appropriate stream protection practices as described in Section 1105.2 when using special design considerations.

1105.7.1 Tailwater

Tailwater at a culvert outlet can greatly affect the size of culvert required at a specific site. For this reason a proper evaluation shall be made of the outlet channel so that a reasonable estimate of the tailwater can be calculated.

A determination of the normal depth of flow in the outlet channel, when the culvert is discharging the design flow, normally establishes the culvert tailwater. A close examination of the downstream channel may however, reveal a temporary or permanent obstruction that will control the operation of the culvert. In some cases, the culvert will outlet near a river or other fluctuating water surface stream that could control its operation.

Where that drainage area of the culvert is very much less than the receiving watercourse (i.e. 100 times) the effect of the receiving watercourse generally may be disregarded.

Where the drainage areas of the culvert and receiving watercourse are nearly equal, concurrent flood peaks may be assumed.

Where there is a significant, but not excessive, difference in the drainage area of the culvert and receiving stream, the following design procedure should be used and the culvert sized using the combination that results in the highest headwater.

A. Compute the culvert headwater using the proper design frequency for the culvert and a lesser frequency for the receiving stream water surface elevation (i.e. culvert tailwater elevation) depending upon the difference in drainage areas; say a 25-year culvert and a 10-year stream.

B. Use 10-year frequency for the culvert and 25-year for the stream.

In some locations, a high tailwater will control the operation of a culvert to such an extent that a substantial increase in pipe size will be required for a negligible decrease in the headwater elevation. For this case, the culvert size should be based on a practical tailwater elevation (e.g. [dc+D]/2).

1105.7.2 Multiple Cell Culverts

A single-cell culvert should be the designer’s first choice within practical limitations.

Occasionally, low headwater requirements, high fills, or bankfull design will create the need for multiple cells. For these cases, it is desirable to limit the number of cells to two. Experience has proven that multiple cells well aligned with a relatively straight channel, will operate satisfactory. However, a bend in the immediate upstream channel may cause the inside cell to collect debris during normal periods of runoff and thereby substantially reduce the capacity of the culvert.

1105.7.3 Improved Inlets

Consider improved inlets attached to the entrance end of the culvert to reduce headwater or culvert size. The improved inlet will alleviate a minimum cover condition and provide for additional headwater depth.

Culverts on relatively steep slopes and controlled by inlet control can see a reduction in the culvert size by furnishing an improved inlet.

Consider the following two general types of inlets in the following order:

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A. Side-taper - A tapered end section from a round to an oval shape for a pipe, or a square to a rectangular shape for a prefabricated box. The length of the taper section is usually made 1.5 times the diameter or rise of the culvert.

B. Slope-taper - A combination of side-taper preceded by a drop in the culvert flow line. The drop can be similar to a paved drop-down entrance or a more sophisticated reinforced concrete drop provided by a formed cast-in-place section with vertical sides.

The improved inlet has the advantage of admitting more flow and thereby tending to fill the culvert barrel and reduce the culvert outlet velocity. The savings in culvert cost must justify the additional cost of the improved inlet.

The Federal Highway Administration has conducted extensive research and studies of improved inlets, and recommended design procedures are included in Hydraulic Engineering Circular No. 13, "Hydraulic Design of Improved Inlets for Culverts."

1106 End Treatments

1106.1 General

Headwalls, or other approved end finishes, shall be provided at the open ends of all Type A, B and C conduits. Headwalls should also be provided for Type D conduits greater than 24 inches in diameter or rise. Generally, headwalls are not recommended for Type E and F conduits.

In order to reduce the entrance loss in culverts, the bell end should be located upstream and the spigot end should be located downstream. Details shown in the plan should convey this to the Contractor when necessary. Figures 1106-2 and 1106-3 show typical end details for a concrete box culvert.

1106.1.1 Usage

The selection of the headwall type is based on safety and economics. Standard HW-2.1 and 2.2 half-height headwalls are recommended for round, elliptical, or pipe arch culverts where a clear zone is provided. Full height headwalls should be provided where a significant reduction in culvert length can be realized with large-span culverts (10 feet or greater) with foreslopes flatter than 2:1 or where right-of-way limits the culvert length. Full-height headwalls shall be provided for prefabricated box culverts and three-sided structures.

The use of special end treatments may be required by Section 602.6 of Volume 1, Roadway Design. Details are available from the Office of Hydraulic Engineering. Justification for the use of this type of end treatment shall accompany the request for details. Miter-cut (step-bevel) end sections, when required, shall be shown on the Culvert Detail Sheet.

When half-height headwalls are provided, they should be built perpendicular to the end of the conduit to eliminate the need for a skew cut. In addition to the required headwall, the upper, or exposed, half of conduits having a diameter or rise greater than or equal to 126 inches shall be miter-cut (step-bevel) to fit the embankment slope.

1106.1.2 End Treatment Grading

The prevailing embankment slope shall be projected to the back edge of the top of the headwall to establish the required culvert length as shown in Figure 1106-1. When the roadway foreslopes are flatter than 2:1, a 2:1 slope shall be provided from the back edge of the top of the headwall to a minimum of 1 foot, with 2 feet, above the top of the culvert. The change in embankment slope shall be warped on each side of the conduit to fit the prevailing slope. In no case shall the distance from the pavement edge to the point where the embankment slope changes to 2:1 be less than the design clear zone width (see Section 601, Volume 1, Roadway Design) unless guardrail is provided.

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Clear zone grading should only be provided at culverts when the requirements of Section 307.2.1 of Volume 1, Roadway Design are met.

The prevailing embankment slope shall be warped on either side of a skewed culvert to assure equivalent soil loading and proper side support of the pipe. This is especially true for flexible pipes with large skews and/or large diameters.

1106.2 Headwall Types

1106.2.1 Half-Height Headwalls

If the size of the conduit exceeds that shown in the Standard Construction Drawing HW-2.1 and HW-2.2 tables, the dimensions shown in the tables may be expanded to accommodate the larger size conduits. Payment for half-height headwalls shall be on a cubic yard basis for Item 602, Concrete Masonry. Masonry quantities for standard half-height headwalls may be obtained from the appropriate standard construction drawing. The quantity of concrete masonry provided in the plans shall be based on the pipe alternate requiring the largest quantity of concrete masonry. 1106.2.2 Full-Height Headwalls

The appropriate full-height headwall for round pipes shown on Standard Construction Drawing HW-1.1 may be considered at the entrance end, when the savings in the reduced size and length of the conduit will offset the additional cost of the headwall. This will most likely apply where corrugated steel pipe is specified, due to cover or size requirements, and the bevel provided for the full-height headwall will substantially reduce the entrance loss. Dimensions of full-height headwalls may be expanded to accommodate pipe sizes larger than 84 inches.

Design full-height headwalls for box, 3-sided and arch culverts per Section 300 of the Bridge Design Manual and the latest “AASHTO LRFD Bridge Design Specifications”. Payment for non-standard full-height headwalls is on a cubic yard basis for Item 511 and pounds of Item 509. Subdivide the quantities for non-standard full-height headwalls in to quantities for headwalls, wingwalls and footers and add plan note D118 to the plans.

Include appropriate plan notes from Section 600 of the Bridge Design Manual in the project plans.

An investigation of the supporting foundation material shall be conducted and the bearing resistance of the foundation material estimated. The level of detail required for the foundation investigation shall be commensurate with the importance of the structure. Such information shall be submitted for all proposed full-height headwall installations and submitted with the Stage 1 review.

The inlet wingwall footings of full-height headwalls shall be armored with Type B rock channel protection, with filter, to preclude scour.

1106.3 Concrete Apron

Provide a reinforced concrete riprap cutoff wall, as shown on Standard Construction Drawings DM-1.1 when the depth of the rock channel protection (if necessary), including the 6 inch granular filter, exceeds the depth of the headwall.

Provide concrete riprap at the inlet end of the culvert where the existing culvert has been undercut. Concrete riprap shall be in accordance with Section 1105.2.3. Concrete riprap is not necessary at the inlet of culverts with full height headwalls that have a footing toe extending 3.5 feet or more below proposed channel grade.

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1107 Rock Channel Protection (RCP)

1107.1 General

RCP is used to control erosion and as a scour countermeasure. It is used at the outlet of culverts and storm sewers, or for lining ditches on steep grades. It is used as a scour countermeasure at wingwalls of full-height headwalls, along footings of 3-sided structures, corner cones, and under bridges.

1107.2 Culvert RCP Types

There are four types of RCP that are used in various situations. The use of the proper type at culvert and storm sewer outlets can be determined from Figure 1107-1. Type A is generally used beyond the outlet of the larger conduits having outlet velocities in excess of 12 feet per second and Type B and C for conduits having an aggregate filter where the protected slope is steeper than 3:1. A filter should always be specified to prevent soil piping through the rock. A geotextile fabric is appropriate in most cases. An aggregate filter should be used when the RCP is under water. The cost of the filter is included in the unit bid price for Item 601 Rock Channel Protection with Filter.

1107.3 Bridge RCP

Furnish RCP armor for bridges over waterways at the following locations:

A. The entire spill-through slopeB. Front side of abutments and wingwallsC. Corner cones

Use the following table to determine the Type of RCP to use:

Channel Mean Velocity (ft/s) RCP Type Thickness (inch)0-8 C 2’-0”

8-10 B 2’-6”above 10 A 3’-0”

Special circumstances such as protection on the outside of curves or in northern regions of the state on pooled water where ice flow is a concern may require greater rock thickness.

Show on the Site Plan the locations, length, and the top of slope elevations for the RCP. Show the RCP in greater detail in the roadway section in conjunction with the channel plans. It is more economical to provide bank protection during the initial construction in order to provide sufficient embankment protection to mini-mize future maintenance.

Limit stream channel excavation to that portion of the channel one foot above normal water elevation in order to minimize intrusion and to preserve the natural low water channel.

1108 Agricultural Drainage

1108.1 Farm Drain Crossings

Where it is necessary to continue an existing farm drain crossing under the highway, the pipe shall be Type B Conduit, one commercial size larger than the existing farm drain within the right-of-way limits.

Occasionally, it will be desirable to provide a farm drain crossing under a highway on new location to satisfy the future need for adequate farm drainage. It is recognized that the required length of a Type B Conduit will provide a betterment for the property owner, but it does preclude the need for a much more expensive

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crossing after the highway is built. Such a crossing is considered a “blind” and the cost of the installation, including suitable terminal markings at the right-of-way lines, will generally not be eligible for federal participation.

1108.2 Farm Drain Outlets

Existing farm drains that outlet through the backslope of the roadway ditch shall terminate with a minimum length of 10 feet of equivalent size Type F conduit. When outletting existing plastic farm drains, one size larger Type F conduit shall be used. An Animal Guard and Erosion Control Pad as shown on Standard Construction Drawing DM-1.1 shall be provided.To provide for possible sedimentation, the invert of the Type F conduit shall be a minimum of 6 inches, with 12 inches being desirable, above the ditch flow line.

1109 Longitudinal Sewer Location

1109.1 Under Pavement

Longitudinal sewers will not be permitted under the pavement of a limited or controlled access facility. Also, the length of transverse sewers under pavements shall be held to a minimum, with the objective of having no manholes in the pavement. Contact OHE if this cannot be accommodated to discuss a possible resolution.

For other facilities, storm sewers should be located outside the limits of the pavement. However, in locations where this would create conflicts with existing utilities (e.g. waterlines, sanitary sewers, gas lines, etc.) the storm sewer may be located under the pavement. Care should be taken to avoid placing manholes in vehicle wheel-paths or within an intersection. Place the center of the manhole in the lane when feasible.

Where an out-to-out clearance of 5 feet cannot be provided between parallel storm and sanitary sewers, premium joints shall be provided on the storm sewer.

1109.2 Under Paved Shoulder

The above shall also apply to paved shoulder areas, unless it is determined that the cost of any other possible location is prohibitive.

1109.3 Approval

Exceptions to the above shall be submitted in the early stages of the design to the Office of Hydraulic Engineering for review and approval.

1110 Reinforced Concrete Radius Pipe and Box Sections

1110.1 General

To comply with the capabilities of manufacturers to provide satisfactory and economical radius pipe or box sections, a minimum radius of 100 feet shall be specified.

The method of manufacturing the radius pipe or box sections will be an option of the producer, subject to inspection and approval by the Ohio Department of Transportation, Office of Materials Management.

As an alternate to radius pipe, pipe specials may be specified to negotiate the specified radius, provided they do not reduce the hydraulic performance established by the initial design. The bends shall be located so that they shall closely follow the alignment of the radius pipe.

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1111 Sanitary Sewers

1111.1 General

Any sanitary sewer, whether new or relocated, shall be constructed using resilient and flexible gasket joints, in accordance with Construction and Material Specification 706.11 for circular concrete pipe or 706.12 for clay pipe. Permissible thermoplastic pipes shall also be specified.

Discharges of treated sanitary flow from abutting property into highway drainage systems are only permitted if the discharge is authorized by the Local Health Department.

1111.2 Manholes

All new manholes for sanitary sewer lines shall be built in accordance with the Standard Construction Drawings. Precast manholes shall have joints in accordance with 706.11 of the Construction and Material Specifications.

1112 Notice of Intent (NOI)

1112.1 General

A NOI is a one-page application form for requesting coverage under a National Pollutant Discharge Elimination System (NPDES) general permit for storm water discharges from Ohio EPA. The applicant(s) must certify their intention to comply with the NPDES general permit by submitting a NOI.

Submit a NOI for all projects where combined Contractor and Project Earth Disturbing Activity (EDA) are one acre or more. In addition, when the combined Project and estimated Contractor EDA are just less than one acre, the project designer may choose to increase the estimated Contractor EDA to avoid the possibility of work on the project being initiated without a NOI. Earth disturbing activity is defined as any activity that exposes bare ground or an erodible material to storm water and anywhere Item 659 Seeding, or Item 660 Sodding is being furnished. An area where pavement is being removed to the sub-grade is considered earth disturbing activity, except for isolated repairs. Routine Maintenance Projects, as defined by Section 1112.2, do not require a NOI.

The Total Earth Disturbing Activity acreage, which includes the Project Earth Disturbing Activity acreage (earth disturbed area within the project construction limits) and the Contractor Earth Disturbing Activity acreage such as: field offices, batch plants, and borrow/waste pits, shall be estimated. The location and size of the Contractor Activities can be estimated using the NOI Acreage Calculation Form (Figure 1112-1).

Non-contiguous portions of projects sold under one contract, such as multiple culvert replacements, may be treated as separate projects for the purposes of obtaining an NOI. If the project sites are located ¼ mile or more apart and the areas between the activities are not being disturbed, the sites can be considered separate. If each site is below the project earth disturbed area threshold of one acre of EDA, no post-construction BMP or NOI will be required. If one or more individual sites meet the project earth disturbed area thresholds, an NOI is required for the project sites that exceed the EDA threshold. The NOI application should reflect the Project and Contractor EDA for all project sites that exceed the threshold. Post-construction BMPs will be required only at the individual project sites that exceed the Project EDA threshold.

Non-contiguous multiple part projects (i.e. Part 1/Part 2) sold as one project should be evaluated with respect to each Part. Parts that meet the definition in Section 1112.2 for Routine Maintenance Projects or have a project EDA under one acre do not need to be included in the disturbed acreage calculations for determining the need for a NOI or post-construction BMP. Post-construction BMPs will be required only for individual parts that exceed the Project EDA threshold. Follow standard NOI procedures for a Project Part with routine maintenance activities exceeding five acres or a Project Part that includes construction (non-routine maintenance) activities.

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For projects where all runoff is collected in a combined sewer, a NOI is not required. However, coordination with the agency responsible for the receiving treatment plant is required.

Prepare a Project Site Plan as required by Location and Design, Volume 3, Section 1308 for all projects that require a NOI or post construction BMPs.

1112.2 Routine Maintenance Project

For the purposes of submitting for coverage under a NPDES permit, a Routine Maintenance Project is one in which all of the Project Earth Disturbing Activities are routine operations that do not change the line, grade, or the hydraulic capacity of the facility and involve total earth disturbing activities of less than 5 acres. Permanent erosion control items shall be included in the plans, if required. Routine maintenance projects do not require a NOI.

Projects with five or more acres of total earth disturbed area cannot be classified as Routine Maintenance Projects.

The following activities are considered routine maintenance activities: Abutment Repairs - repairs to bridge abutments Bridge Deck Overlays - replacing the wearing surface on bridges Bridge Deck Replacement - replacing the entire deck on bridge Chip Sealing - placing asphalt or polymer binder and stone on existing paved roadways Fence Repair / Replacement - repairing or replacing existing fencing and/or posts Lighting Maintenance Loop Detector Repairs - repairing loop detectors in existing pavement Pothole Filling Tree/brush Removal Signal Installation / Maintenance - installing / repairing / replacing traffic signals and poles where

previous ones existed Signing Maintenance - repairing / replacing traffic signs and posts Noise Wall Repair Full Depth Pavement Repairs - isolated repairs of pavement build-up down to subgrade (potholes,

utilities) Partial Depth Pavement Repairs - isolated repairs of surface courses of pavement Linear Grading - reshaping of graded shoulders to establish proper drainage away from pavement Berm Repair or Topsoil placement along shoulders - placing berm material or topsoil on shoulders

adjacent to pavement to eliminate drop-offs. Ditch Cleanout - maintaining or restoring original flow line and cross-section only Guardrail Installation / Replacement - installing / repairing with minor grading work to create proper

grade for end assemblies where previous guardrail existed. Culvert Replacement - replacing a culvert with same line, grade and hydraulic capacity; must be

within parameters of the USAC Nationwide Permit #3. Culvert Repair / Lining - repairing or lining existing culvert maintaining same line, grade and

hydraulic capacity, must be within parameters of the USAC Nationwide Permit #3 Resurfacing - replacing several inches of asphalt wearing course by milling existing asphalt and

replacing with new. Curb Repairs - repairing existing curbing along a roadway. Sidewalk – replacement of sidewalk without other drainage or roadway improvements. Isolated slide repairs.

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Post construction storm water best management practices are not required for routine maintenance projects.

1112.3 Watershed Specific NOI Requirements

Additional requirements for projects located in certain designated watersheds are required by Ohio EPA. These projects require coverage under an Ohio EPA watershed specific NPDES permit.

Coordinate projects in the following watersheds with Central Office – Office of Hydraulic Engineering:

Big Darby Creek (entire watershed) Olentangy River (portion of watershed as regulated under permit number OHC200002)

In addition to post-construction BMP requirements, watershed specific NPDES permits include the following requirements:

Groundwater Recharge Mitigation, if applicable Riparian Setback Mitigation Temporary Sediment Basin Locations Ohio EPA review and approval of the Storm Water Pollution Prevention Plan (SWPPP)

Provide groundwater recharge calculations, riparian setback calculations, and temporary sediment basin locations to Central Office – Office of Hydraulic Engineering with the BMP submittals as outlined in Section 1116.2. Groundwater recharge calculations and riparian setback calculations shall be based on impacts outside the existing roadway right-of-way. Determine the riparian setback limits according to the Permit and identify the setback limits on the Project Site Plan.

Mitigation for groundwater and riparian setback will be determined through coordination between the District, Central Office – Office of Hydraulic Engineering and Ohio EPA prior to submittal of the NOI application.

Determine soil types required for groundwater recharge calculations using the NRCS Web Soil Survey website.

While sediment basin locations are typically provided by the Contractor, designers of projects being developed under watershed specific NPDES permits shall identify locations with capacity to store sediment volumes required by these permits. The location and calculations for the sediment basins shall be shown on the Project Site Plan. Additional temporary sediment and erosion control features will be added to the SWPPP by the Contractor.

Submit the NOI, Project Site Plan, proposed mitigation and supplemental calculations to the Ohio EPA at least two months prior to plan package submittal to ensure that there are no delays.

1113 Erosion Control at Bridge Ends

1113.1 General

Collect and carry bridge deck drainage that flows off the ends of the bridge in accordance to the following:

A. Flow less than 0.75 ft3/s or for bridges without MSE walls – Furnish a flume, as shown on Standard Construction Drawing DM-4.1,

B. Flows greater than 0.75 ft3/s or bridges without MSE walls - Furnish an integral curb provided on the approach slab with a standard catch basin located off the approach. Include a bridge terminal assembly at the trailing end of bridge barrier. Use a Catch Basin No. 3A, as shown on Standard Construction

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Drawing CB-2.2. Provide Type F conduit (707.05 Type C) for an outlet down the embankment slope and armor the outlet to prevent erosion.

C. Bridges with MSE Walls– Furnish a barrier on the approach slab with a standard inlet basin. Locate the inlet a minimum of 25 feet beyond the limits of MSE wall soil reinforcement. Continue the barrier a minimum of 10 feet past the inlet.

1113.2 Corner Cone

Place Item 670 Slope Erosion on all bridge approach embankment corner cones, beginning at the edge of the crushed aggregate or concrete slope protection.

1114 Temporary Sediment and Erosion Control

1114.1 General

Temporary sediment and erosion control is required on all projects that have Earth Disturbing Activities as outlined in Supplemental Specification 832. A Storm Water Pollution Prevention Plan (SWPPP) is required as outlined in SS 832. Projects that may have environmental impacts to habitat or species may also be required to prepare a SWPPP as determined by the District Environmental Coordinator. The SWPPP requirements are outlined in Supplemental Specification 832.

1114.2 Cost Estimate for Temporary Sediment and Erosion Control

For all projects that require temporary sediment and erosion control furnish a dollar amount to be encumbered in the final plan package. Use the temporary sediment and erosion control estimator located in the Design Reference Resource Center to develop this amount.

1115 Post Construction Storm Water Structural Best Management Practices

1115.1 General

Post Construction Storm Water Best Management Practices (BMP) are provided for perpetual management of storm water runoff quality and quantity so that a receiving stream’s physical, chemical and biological characteristics are protected and stream functions are maintained.

BMPs are required per the Ohio EPA’s NPDES permit(s), which include the Construction General permits and the Municipal Separate Storm Sewer System (MS4) permits. Two variants of the MS4 permit are possible depending on the population size of the entity seeking coverage as follows:

Small MS4 – Entities that have populations less than 100,000 within urbanized areas.

Individual MS4 – Entities that have population in excess of 100,000. Several categories exist under the individual MS4 permit.

Local entities that administer a small or individual MS4 permit may have more restrictive language regarding selection and use of BMPs as compared to the Department. Storm water discharge from ODOT right-of-way is permitted under the OEPA Small MS4 permit that is obtained by the Department. While the local entity cannot force the Department to use their standards, it may be possible for the Department to incorporate the needs of the local entity subject to review and approval of OHE.BMP, as described in Section 1117, shall meet permit compliance for Ohio EPA’s NPDES General Permits. For ODOT projects, any proposed alternative BMPs that are not found in Section 1117 require submittal to ODOT Central Office – Office of Hydraulic Engineering. A review and approval of the alternative BMP by

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ODOT Central Office – Office of Hydraulic Engineering and Ohio EPA is required. Local-Let Local Public Agency projects may use an alternative post-construction BMP criteria with Ohio EPA approval.

Post-construction BMP remove pollutants from runoff (water quality treatment) and protect streams by attempting to maintain existing stream conditions or by reducing runoff volumes through structural BMP (water quantity treatment).

Locate BMPs so that they are protected in accordance with Location and Design Manual, Volume 1.

1115.2 Project Thresholds for Post-Construction BMP

Post-construction BMP are required through Ohio EPA’s NPDES Construction General Permit for construction storm water discharges. The requirements to provide post-construction BMP established in the NPDES General Permit are based on Project Earth Disturbing Activities. If a NOI is not required (Section 1112), then post construction BMPs are not needed.

Project Earth Disturbing Activity (EDA) is defined as any activity that exposes bare ground or an erodible material to storm water or anywhere Item 659 Seeding, Item 660 Sodding is being furnished. An area where pavement is being removed to the sub-grade is considered earth disturbing activity, except for isolated repairs.

Requirements based on project EDA for non-routine maintenance projects are listed below:

Table 1115-1Project Earth Disturbed Area Thresholds

EDA < 1 acre - BMP not required.

EDA 1 - BMP are required.

Routine Maintenance Projects as defined in Section 1112.2 do not require post-construction BMP.

Provide post-construction BMP for all projects exceeding the project EDA thresholds in Table 1115-1. For projects requiring post-construction BMP, the following items require evaluation:

Need for Water Quantity and Quality Treatment vs. just Water Quality Treatment(Section 1115.3) What is the Project Type – Redevelopment or New Construction (Section 1115.6) If New Construction, calculate the Treatment Percent (Section 1115.7) Project-wide or site specific implementation of BMPs to reach the required treatment (Section

1115.7) Applicable BMP to be implemented (Section 1117)

All projects, including Local Public Agency projects (ODOT-let and Local-Let) are required to provide post-construction BMP as indicated in Table 1115-1. Projects with post-construction BMP require coordination with LPAs when BMPs are required outside ODOT right-of-way. Inform the LPA of maintenance responsibilities associated with post-construction BMP.

Non-contiguous portions of projects sold under one contract that do not require an NOI, as described in Section 1112.1, do not require post-construction BMP.

1115.3 Water Quality and Water Quantity Treatment

Projects exceeding the minimum thresholds in Section 1115.2 must address water quality (pollutant removal) and potentially water quantity (stream protection/volume control) post-construction BMP.

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BMPs to address water quantity are not required for projects that meet any of the following criteria:

Redevelopment projects as defined in Section 1115.6.1. New Construction Projects as defined in Section 1115.6.2 where one or less acre of new

impervious area is created in new permanent right-of-way area being acquired for the project. Portions of New Construction Projects (as defined in Section 1115.6.2) which discharge directly to

a large river (>100 square mile drainage area or fourth order or greater) or to a lake and where the development area is less than 5 percent of the watershed area upstream of the development site, unless known water quality problems exist in the receiving waters. Only the project areas that drain to a large river or lake will be excluded from the requirement to provide quantity treatment. If portions of a project discharge to smaller waterbodies, quantity treatment may still be required for those portions. If there is a question regarding the stream classification, contact Central Office - Office of Hydraulic Engineering.

Projects may not be subdivided into multiple NOIs for the sole purpose of attempting to reduce post construction treatment requirements.

A map of stream classifications can be found at ODOT’s TIMS website:http://gis.dot.state.oh.us/tims/Map/HydraulicEngineering Click “HUC - Stream Order” to view stream layers. BMPs that treat water quality and water quantity include:

Extended Detention Retention Basin Bioretention Cell Infiltration Trench Infiltration Basin Constructed Wetlands

BMPs that treat only water quality include:

Manufactured Systems Vegetated Biofilter Vegetated Filter Strip

BMPs that treat only water quantity and must be paired with a water quality BMP include:

Stream grade control structures (within Waters of the U.S.) Underground Extended Detention

1115.4 Water Quality Volume

Water quality volume is directly used to determine sizing for the following BMP:

Extended Detention Retention Basin Infiltration Trench Infiltration Basin Constructed Wetlands

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The water quality volume (WQv) is used to define the amount of storm water runoff from any given storm that should be captured and treated in order to remove a majority of storm water pollutants on an average annual basis. The following equation shall be used to calculate the water quality volume:

WQv = (P*A*Cq)/12

Where:WQv = Water Quality Volume (Acre-feet)P = Precipitation (0.75 inches)A = Contributing Drainage Area (acres) Cq = 0.858i3 - 0.78i2 + 0.774i + 0.04(see figure 1115-1)i = impervious area divided by the total area Cq = 0.9 when all drainage area is impervious.

1115.5 Water Quality Flow

Use water quality flow to determine sizing for manufactured systems and vegetated biofilters.

The water quality flow (WQf) is the discharge that is produced by using an intensity of 0.65 in/hr in the rational equation (section 1101.2.2). Use the entire contributing drainage for the WQf calculation.

1115.6 Project Type - Redevelopment and New Construction

1115.6.1 Redevelopment Projects

Redevelopment projects include: Projects constrained entirely within existing right-of-way, or Projects that do not add new impervious area in new permanent right-of-way

While all areas within existing ODOT right-of-way may not be covered by impervious surfaces, the area within existing ODOT right-of-way is considered impervious area for the purpose of post-construction BMP design considerations. Therefore, consider all area within existing right-of-way to be impervious with a runoff coefficient of 0.90 when performing post-construction BMP calculations.

1115.6.2 New Construction Projects

Projects that add new impervious area inside new permanent right-of-way are considered new construction projects.

New construction projects allow for the reduction of treatment requirements based on the amount of new impervious area relative to the existing impervious area within the project EDA (See Section 1115.7). Consider all area within existing ODOT right-of-way to be impervious for post construction BMP calculations.

1115.6.3 Pedestrian Facilities and Shared Use Paths

For Redevelopment Projects or New Construction Projects that include EDA only associated with pedestrian facilities and shared use paths, with no EDA from planned roadway improvements, narrow Vegetated Filter Strips are an acceptable post-construction BMP (as discussed in Section 1117.2.1). For these projects, quantity treatment (as discussed in Section 1115.3) is not required.

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1115.7 Treatment Requirements for Projects

The amount of treatment required for a project to meet the NPDS Permit requirements is based on the project earth disturbed area and the weighted average for new and existing impervious area.

Use a Treatment Percentage (T%) of 20% for redevelopment projects.

Determine the Treatment Percent for New Construction projects using the following equation:

T% = [(Aix * 20)+(Ain * 100)] / (Aix+Ain)

Where:T% = Treatment percent (Percentage)Aix = Project EDA that is inside the existing right of wayAin = Inside new permanent right of way, Ain is the new impervious area minus any impervious area that is removed Consider all area within existing ODOT right-of-way to be impervious for post-construction BMP

calculations.

Area draining to a post-construction BMP will earn treatment credit equal to the amount of ODOT right-of-way area treated by the BMP.

Projects utilizing BMPs designed based on WQv or WQf require treatment according to one of the following:

Provide T% treatment of the WQv or WQf for 100% of the project earth disturbed area Provide 100% treatment of the WQv or WQf for T% of the project earth disturbed area

Projects utilizing Vegetated Biofilters, Vegetated Filter Strips and Bioretention Cells require treatment as follows:

Provide 100% treatment of the contributing drainage area for T% of the project earth disturbed area in a specified portion of the project. For example, a redevelopment project with 10 acres of project EDA may provide treatment through the use of a vegetated biofilter with 2 acres of contributing drainage area. The vegetated biofilter design would be based on the contributing drainage area to the ditch of 2 acres.

For all scenarios, size the BMP based on the entire contributing drainage area, offsite and on-site, to the BMP.

When providing treatment based on a percentage of the project earth disturbed area, consider the following:

Credit for water quality and water quantity treatment is only applied to the portion of the contributing drainage area within ODOT right-of-way (on-site). Any offsite contributing drainage area must be included in the BMP calculations for sizing purposes (i.e. width of ditch, etc.). However, the offsite area will not be included in the reduction of the required amount of project EDA that requires treatment. Example: A vegetated biofilter that has offsite contributing drainage area of one acre and on-site contributing drainage area of two acres (total drainage area of three acres) would result in a treatment credit of two acres. The vegetated biofilter must be sized for the total contributing drainage area of three acres. Multiple areas of a project may provide treatment to meet the total area required for compliance with the NPDES Permit. If the total area requiring treatment in this example was four acres, another vegetated biofilter with a minimum of two acres of on-site tributary area would be needed to meet the treatment requirements.

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For projects with multiple distinct stream crossings that do not immediately share a common confluence downstream, provide post-construction BMP treatment proportional to the amount of Project EDA tributary to each stream.

1116 BMP Selection and Submittals

1116.1 BMP Selection

Selection of BMP shall be based on providing maximum runoff treatment while minimizing impacts to the remaining project design features, including utilities and right-of-way. In addition, each BMP option comes with unique maintenance requirements. Contact the Office of Maintenance Administration for detailed BMP maintenance information.

Approval from Ohio EPA is required to use alternative BMPs not listed in Section 1117. Alternative methods will be approved or denied on a case-by-case basis if the alternative methods are demonstrated to sufficiently protect the overall integrity of the receiving streams and the watershed. For curbed roadways, total contributing drainage areas to sumps or intersections that are less than or equal to 0.25 acres as shown in figure 1116-1 do not require a BMP. Note that these exceptions are unique circumstances. Provide BMP as necessary for all other project features.

For projects where the drainage sheet flows off the roadway and continues outside existing or proposed right-of-way, do not channelize flow for the sole purpose of providing a post-construction BMP. Treatment is not required for areas where sheet flow off the roadway continues to sheet flow outside ODOT right-of-way. Areas where this occurs should be documented in the post-construction BMP calculations and identified on the Project Site Plan.

Design criteria for all BMP are available in Section 1117. A flow chart to determine BMP treatment requirements is provided in Figure 1115-2.

1116.2 BMP Submittals

Consider BMPs early in the design process to allow for right-of-way and utility coordination as well as evaluation with respect to waterway permitting issues.

For PDP projects characterized as Paths 4 and 5, provide a description of the planned BMPs to be used for the project in the Preliminary Engineering Phase (PE). Final BMP design is required during Stage 1 plan development as identified in later tasks of the Preliminary Engineering Phase. Further refinement may be needed within the Environmental Engineering Phase. For projects categorized as Paths 1-3, it is unlikely a conceptual BMP task will be needed. Include BMPs in the Environmental Engineering Phase and potentially the Final Engineering Phase of the PDP.

Submit the BMP final design during Stage 1 to ODOT Central Office – Office of Hydraulics. Include the following information:

Estimated Project Earth Disturbed Area Treatment Percent Calculation or justification that project is a Redevelopment Project. BMP selected for use Drainage area mapping for post-construction BMP’s that show the total contributing drainage area

and the amount of contributing drainage area within ODOT right-of-way. Plan sheets showing locations of post-construction BMP Calculations for each BMP (Sec. 1117) Explanation for any area that is not treated (i.e. environmental commitment, total parcel take,

environmental resource impact, sheet flow runoff, etc.)

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The following design resources are available on the ODOT, Office of Hydraulic Engineering’s website:http://www.dot.state.oh.us/Divisions/Engineering/Hydraulics/Pages/PostConstructionStormWaterBMP.aspx

Post-Construction BMP Design Review Checklist BMP Calculation Spreadsheet Post-Construction BMP Design Examples Post-Construction BMP Training Workshop Slides

Identify the final locations and EDA treatment credit of each individual post-construction BMP in the Project Site Plan as described in Section 1308 of Location and Design Manual, Volume 3. If applicable, provide cross-references to sheets showing post-construction BMP details on the Project Site Plan.

1117 BMP Toolbox

1117.1 Manufactured Systems

Manufactured systems consist of underground structures that treat the water quality flow (WQf) by removing particulate matter through settlement or filtration. Supplemental Specifications 895 and 995 cover the material and performance criteria for these devices. They are placed in an off-line configuration with manholes to allow for routine maintenance procedures (see figure 1117-2). Use the following procedure for design of manufactured systems:

A. Determine the total contributing drainage area.

B. Calculate the WQf according to Section 1115.5.

C. If appropriate, reduce the WQf according to Section 1115.7.

D. Provide a No. 3 Manhole, With ___” Base ID and ___” Weir where flow is to be diverted to the off-line manufactured system according to Table 1117-1 and 1117-2 and the calculated WQf.

Table 1117-1Manufactured Systems

Type WQf (cfs)

No. 3 Manhole Base ID (inches)

611 – Type B Conduit Diameter (inches)

1 1 84 122 2 90 153 3 96 184 6 108 24

Reserve an area (as measured from the centerline of the No. 3 Manhole) according to Table 1117-2:

Table 1117-2Reserved Area for Manufactured System

Type Width (ft)

Length (ft)

611 – Type B Total

Conduit Length (ft)

Weir Height

(inches)

1 15 30 20 62 20 32 30 83 25 33 40 94 25 37 40 12

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E. Furnish two lengths of 611, Type B Conduit placed perpendicular to the inflowing sewer (see Table 1117-2 for the total length required).

F. Reserve an area (as measured from the centerline of the No. 3 Manhole) according to Table 1117-2. If this area is not attainable, contact Central Office – Office of Hydraulic Engineering for further guidance. Ensure the area is void of all utilities and is accessible for routine cleanout and maintenance.

For manufactured systems located along a roadway with a posted speed limit over 45 mph, locate the area for the manufactured system outside all paved areas.

For manufactured systems located along a roadway with a posted speed limit of 45 mph and less, it is preferred to locate the area for the manufactured system outside paved areas. If it is not feasible to locate the area outside of the paved area, select another BMP or contact Central Office – Office of Hydraulic Engineering for further coordination.

When a manufactured system is connected to a storm sewer with a depth exceeding 10 feet, contact Central Office – Office of Hydraulic Engineering.

Manufactured systems are typically not suited for treatment of flows in large trunk sewers. As indicated in Table 1117-1, manufactured systems should not typically be provided on sewers that are carrying a water quality flow greater than 6 cfs. The water quality flow calculation is based on the entire contributing drainage area to the storm sewer.

Add “Item 895, Manufactured Water Quality Structure, Type__” to the plans when using a manufactured system.

Label the location and EDA treatment credit on the Project Site Plan for each manufactured system on the project.

1117.2 Vegetation Based BMP

1117.2.1 Vegetated Filter Strip

A Vegetated Filter Strip is a BMP that filters storm water through vegetation. The Vegetated Filter Strip consists of the grassed portion of the graded shoulder and the grassed foreslope. The Vegetated Filter Strip must be void of gullies or concentrated flow. The water flow is characterized as overland flow throughout the grass.

All areas that contribute to a slope that meets the Vegetated Filter Strip criteria in Table 1117-3 receive a treatment credit that is equal to the area of the roadway contributing to the slope and the area of the slope.

Table 1117-3Maximum

Pavement Width(ft)

Slope (H:V) Filter Strip Width(ft minimum)

22 3:1 and flatter 15 24 3:1 and flatter 1726 3:1 and flatter 18.528 3:1 and flatter 20.530 3:1 and flatter 2232 3:1 and flatter 2434 3:1 and flatter 25 48 6:1 and flatter 25

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The Vegetated Filter Strip width is measured down the grass slope starting at the grass and ending at the inside edge of the ditch bottom.

Any area associated with concentrated flows that outlet to a Vegetated Filter Strip should not be included in the treatment credit.

For projects that include EDA only associated with pedestrian facilities and shared use paths, with no EDA from planned roadway improvements, widths of Vegetated Filter Strips are allowed to be narrower than those in Table 1117-3. Vegetated Filter Strips are an acceptable post-construction BMP for these projects provided the following criteria are met:

The minimum Vegetated Filter Strip width is equal to the width of the contributing impervious area. The maximum slope of the Vegetated Filter Strip is 3:1. All runoff must be sheet flow, with no concentrated flows to the Vegetated Filter Strip.

Example 1: A project includes the addition of 4-foot wide sidewalk along a road to the extent that the project EDA is greater than 1 acre, but no roadway improvements are included. That project may incorporate 4-foot wide Vegetated Filter Strip collecting runoff from the sidewalk in order to meet its post-construction treatment requirements.

Example 2: A project includes the addition of a 10-foot wide bike path, but no roadway improvements are included in the project. The project may incorporate 10-foot wide Vegetated Filter Strip collecting runoff from the bike in order to meet its post-construction treatment requirements.

Similarly to standard Vegetated Filter Strip, treatment credit for narrow Vegetated Filter Strip will be given to the impervious area draining to the filter strip as well as the area of the filter strip itself.

Projects that have EDA from a combination of pedestrian facilities or shared use path as well as roadway improvements may not utilize Vegetated Filter Strip narrower than those shown in Table 1117-3 without project-specific permission from Ohio EPA.

Label the station range and location, and the EDA treatment credit on the Project Site Plan for each Vegetated Filter Strip provided on the project.

Add 4” of Item 659, Topsoil, to the grass portion of the shoulder and foreslope of the Vegetated Filter Strip.

Add Item 670, Slope Erosion Protection, to the plans when using Vegetated Filter Strip.

1117.2.2 Vegetated Biofilter

If the Vegetated Filter Strips will not provide the required treatment, consider using a Vegetated Biofilter.

A Vegetated Biofilter (VBF) is a BMP that filters storm water through vegetation and potential infiltration. The Vegetated Biofilter consists of the grassed portion of the graded shoulder, grassed foreslope, and flat grassed ditch. The purpose of the Vegetated Biofilter is to allow runoff to spread out and move slowly through a shallow, flat, and grassed conveyance. Vegetated Biofilter must be void of rills, gullies, or visible erosion on the grassed foreslope of the ditch as well as in the bottom of the ditch.

When widening existing ditches, consider the following before purchasing new right-of-way:

Provide a steeper ditch foreslope. Provide a steeper ditch backslope. Reducing the bench width to a minimum of 4 feet.

Consider soil conditions and safety issues prior to making any of the above changes to the existing slopes or benches.

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Changes to existing ditches may be regulated through waterway permits since ditches may be considered streams or wetlands. All impacts to existing streams and wetlands should be avoided or minimized to the maximum extent practicable. To determine if the proposed ditch will impact an existing stream or wetland, contact the District Environmental Coordinator.

For projects utilizing the vegetated biofilter, provide a ditch width using the Enhanced Bankfull Width (EBW) or “Standard” ditch width to provide water quality treatment. Use the following steps to determine the ditch width:

A. Determine Enhanced Bankfull Width (EBW):

The EBW is the width in a trapezoidal ditch for which the following criteria are met: The minimum EBW is 4 feet. The depth of flow for the water quality flow rate (WQf) is less than or equal to 4 inches. The velocity of flow for the water quality flow rate (WQf) is less than or equal to 1 ft/sec.

Use the water quality flow rate (WQf) per section 1115.5.

Use Manning’s Equation to determine the depth and velocity of flow:

Manning’s Equation:

𝑄 = 1.49

𝑛 ∗ 𝐴𝑅2

3 ∗ 𝑆1

2

Where:Q = flow rate (cfs)n = Manning’s Roughness Coefficient (0.15)A = Cross section area of flow (ft2)R = Hydraulic Radius (ft) (Area / Wetted Perimeter)S = Longitudinal Slope of ditch (ft/ft)

There is not a direct calculation to determine EBW. Use a trial and error method to determine a width for which the depth and velocity criteria are met for the WQf, assuming open channel flow. The EBW should be whole numbers only, no half-foot increments. The enhanced bankfull width corresponds to the dimension of the bottom width of the trapezoidal ditch.

B. Determine “Standard” Ditch Width:

Determine the size of the trapezoidal ditch that would typically be specified for the project without accounting for water quality treatment (use typical roadway design practices).Use the bottom width dimension of the trapezoidal ditch. Ignore any rounding lengths associated with the trapezoidal ditch.

C. Determine the vegetated biofilter ditch width required for water quality treatment as described below:

1. If the EBW is less than or equal to the ”Standard” ditch width, furnish the “Standard” ditch.

2. If the EBW is greater than the “Standard” width, furnish the EBW.

The EBW can be calculated at multiple locations along its length. This would allow the width to be reduced where there is less tributary area (i.e. the upstream area of the ditch). However, use the entire contributing drainage area to the location in the ditch being evaluated to determine the EBW.

At points where concentrated offsite runoff is accepted, the EBW should be recalculated.

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Treatment credit for Vegetated Biofilter is given to:

1. Areas within the project limits that sheet flow off of the roadway into a grassed shoulder, grassed foreslope, and then into a grassed trapezoidal ditch sized as described above. (Tributary areas to a Vegetated Biofilter that do not meet this criteria, i.e. drainage from concentrated flow or outside project limits, must be included in the determination of the EBW, but do not receive treatment credit.)

2. The area of the defined Vegetated Biofilter (the shoulder, foreslope, ditch bottom, and backslope) within the permanent right-of-way.

Ensure that rock or other impervious soil layers will not prevent grass from being established at the invert of the flowline. If the velocity is such that rock channel protection, reinforced concrete mats, or SS836 are required, that section of the ditch cannot be used as a Vegetated Biofilter.

Use of Vegetated Biofilter with grassed foreslopes steeper than 3:1 must be coordinated with the District Maintenance department to ensure that maintenance of is feasible.

Constriction points in the enhanced bankfull width at drive pipes or other drainage related features are acceptable. A transition back to the calculated width shall be made immediately following the constriction point.

Label the station range and location, and EDA treatment credit on the Project Site Plan for each Vegetated Biofilter provided on the project.

Add 4” of Item 659, Topsoil, to the grass portion of the shoulder and foreslope of the Vegetated Biofilter.

Add Item 670, Ditch Erosion Protection, to the plans when using Vegetated Biofilter.

1117.3 Extended Detention

Extended detention is a method that captures storm water during rain events and slowly releases the captured volume over a period of time. The WQv is used to determine the storage volume of the detention basin. The WQv is discharged over a 48 hour time frame. Increase the WQv by 20% when sizing the BMP to allow for sedimentation to occur. Detention can be either above or below ground. Detention basins that are above ground should be used when feasible. However, when project site parameters dictate, an underground system may be considered.

Due to the safety considerations and potential impacts to the drainage system, the use of extended detention BMPs requires approval from the Office of Hydraulic Engineering. Provide submittals according to Section 1116. Extended Detention BMPs with more than one foot of ponding water are not to be located in the clear zone without prior approval from the Office of Roadway Engineering.

1117.3.1 Detention Basin

A detention basin is a dry pond that detains storm water for quality and quantity. Use the following procedure for design of the detention basin:

A. Calculate the WQv per Section 1115.4.

B. Calculate the Design Check Peak Discharge per Section 1117.3.3.

C. Increase the calculated WQv by 20% to determine the required size of the detention basin.

D. Provide a forebay (settling pool located at the inlet to the basin) that is 10% of the WQV (located according to Figure 1117-5), if feasible. The forebay volume is part of the required volume, and is not an additional volume requirement.

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E. Provide a micropool (settling pool located at the outlet of the basin) that is 10% of the WQV , if feasible. The micropool volume is part of the required volume, and is not an additional volume requirement.

F. Size the water quality basin (outlet structure) for proper discharge of the WQv and the weir for proper discharge of events up to the design check discharge according to Section 1117.3.1.1. Ensure that the water surface elevations created by the basin are considered in the design of the upstream drainage system.

G. Provide anti-seep collars for the outlet pipe according to Section 1117.3.1.2.

The following criteria apply when designing a detention basin:

A. Use side slopes of 4:1 (max)

B. Consider vehicle access to the basin for periodic maintenance.

C. Do not locate on uncompacted fill or steep slopes (2:1 or more) or where infiltrating ground water could adversely impact slope stability.

D. Vegetate the sides of the basin with Item 670 Slope Erosion Protection.

E. Embankment work to create the impoundment will be constructed and paid for as Item 203 Embankment, Using Natural Soils, 703.16.A.

F. Furnish gravel pack protection at the outlet structure (see SCD WQ1.1).

G. Place channel protection (RCP or Tied Concrete Block Mat) at the entrance of the basin to minimize erosion and sediment resuspension.

H. Furnish a Water Quality Basin, Detention per section 1117.3.1.1

I. Label the location and EDA treatment credit on the Project Site Plan for each extended detention basin on the project.

1117.3.1.1 Water Quality Basin and Weir

Furnish an outlet structure that fully drains the WQv in 48 hours or more. No more than 50% of the WQv should be released from the detention basin in less than one-third the drain time (i.e. 16 hours).

The outlet structure consists of a catch basin with a perforated riser pipe on the inlet side and a conduit on the outlet side. The perforated riser pipe is used for flow control to achieve the required discharge time. A gravel envelope surrounds the perforated riser pipe along the inlet side of the catch basin to prevent blockage of the orifice holes in the pipe. The catch basin and riser pipe are paid for as Item 611, Water Quality Basin, Detention. Details of a perforated riser pipe outlet structure can be found on standard drawing WQ1.1.

The equation for a single orifice is:

Where:A = Area of orifice (ft2)H = Head on orifice as measured to the centerline of the orifice (ft)C = Orifice coefficient

Q A C 64.4H

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Table 1117-4Orifice Coefficient Guidance

C Description

0.66Use for thin materials where the thickness is equal to or less than the orifice diameter.

0.80 Use when the material is thicker than the orifice diameter.

From CALTRANS, Storm Water Quality Handbooks, Project Planning and Design Guide, September 2002.

Furnish a weir to allow the design check discharge to bypass the structure without damage to the detention basin or embankment of the basin. The design check discharge shall be determined per 1117.3.3. Ensure that the weir is protected from erosion. A hydrograph curve for the outlet will be required to calculate the discharge time of the WQv and the design check discharge (see 1117.3.3). The discharge time should correspond to the minimum drain time of 48 hours with no more than 50% of the WQv being released from the detention basin in less than one-third of that 48 hour drain time.

Generally, it is easier to model the outlet structure and discharge time using software such as Pond Pak or HydroCad to develop the hydrograph.

1117.3.1.2 Anti-Seep Collar Design

Furnish anti-seep collars on conduits through earth fills where water is being detained. The following criteria apply to anti-seep collars:

A. Furnish a minimum of 2 collars per outlet conduit. Increase the seepage length along the conduit by a minimum of 15%. This percentage is based on the length of the pipe in the saturation zone.

B. Anti-seep collars should be placed equally within the saturation zone. Place one collar at the end of the saturation zone. In cases where the spacing limit will not allow this, place at least one collar within the saturation zone.

C. Maximum collar spacing should be 14 times the minimum projection above the pipe, but not more than 25 feet. The minimum collar spacing should be 5 times the minimum projection, but not less than 10 feet.

D. Extend the collar dimensions a minimum of 2 feet in all directions around the outside of the conduit, measured perpendicular to the conduit. Center the anti-seep collars around the conduit.

E. The top of collar shall not be less than 6 inches below, measured normal to, the finished ground line.

F. All anti-seep collars and their connections shall be watertight.

G. Minimum thickness shall be 6 inches.

H. Payment for the collar shall be Item 602 Concrete Masonry (see standard construction drawing WQ-1.2).

The design procedure for anti-seep collars is as follows:

1. Determine the length of the conduit within the saturated zone. The assumed normal saturation zone can be determined by projecting a line through the embankment, with a 4:1 (H:V) slope, from the point where the normal water elevation (10-year) meets the upstream slope to a point where it

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intersects the invert of the conduit. This line, referred to as the “phreatic line”, represents the upper surface of the zone of saturation within the embankment (See Figure 1117-11). The 10-year storm pool elevation is the phreatic line starting elevation.

Ls = Y(Z+4)[1+S/(0.25-S)]

Where:Ls = Length of the conduit in the saturated zone (feet)Y = Depth of the water at the spillway crest, 10-year frequency storm water surface elevation (feet)Z = Slope of the upstream face of the embankment (Z feet horizontal to 1 foot vertical)S = Slope of the conduit (feet per foot)

2. Determine the required seepage length increase.

Ls = 0.15Ls

3. Choose a collar height and width that is at least 4 feet larger than the outside diameter of the conduit (minimum projection of 2 feet from all sides of the conduit). Give collar sizes in one foot increments.

P = W – D

Where:P = Projection of collar (feet)W = Height or width of collar (feet)D = Inside diameter of conduit

4. Determine the total number of collars required. The collar size can be increased to reduce the number of collars. Alternatively, the collar size can be decreased by providing more collars. In any case, increase the seepage length by a minimum of 15%.

No. of collars required = Ls/P

1117.3.2 Underground Detention

Underground detention areas are made up of a series of conduits. They range from an oversized storm sewer to a series of conduits that are specifically used for storm water detention. Underground detention is only to be used for stream protection (water quantity treatment). Underground detention cannot be used for pollutant removal (water quality treatment) without approval from Ohio EPA. The following criteria apply when designing underground detention:

A. Ensure the Hydraulic Grade Line design of the storm sewer will pass through the structure and meet the requirements of 1104.4.2.

B. Furnish an outlet structure that fully drains the WQv in 48 hours or more. No more than 50% of the WQv should be released from the detention basin in less than one-third the drain time (i.e. 16 hours).

C. Locate access to the conduits for periodic maintenance so that traffic impacts are minimized.

D. If practical, provide pretreatment of the storm water with vegetation.

E. Payment for the conduit shall be: Item 611 ____” Conduit, Type____, for underground detention.

F. Label the location and EDA treatment credit on the Project Site Plan for each underground detention on the project.

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1117.3.3 Design Check Discharge

A design check discharge with the frequency of a 10-year event shall be used. Use the entire drainage area that contributes to the BMP to calculate the design check discharge.

1117.4 Retention Basin

A retention basin is a “wet” pond that has a minimum water surface elevation between storms that is defined as the permanent pool. Above the permanent pool is a detention pool that provides storage for 75% of the WQv and drains in 24 hours or more. The detention volume above the permanent pool is called the Extended Detention Volume (EDv). The full storage water depth is typically between 3-6 feet and the volume is less than 15 Ac-ft. The permanent pool is sized to provide storage for 75% of the WQv. A retention basin may be considered for large tributaries, but it may require a large amount of space.

Use the following procedure for design of the retention basin:

A. Calculate the WQv per Section 1115.4.

B. Calculate the Design Check Peak Discharge per Section 1117.3.3.

C. If feasible, provide a forebay (settling pool located at the inlet to the basin) that is 10% of the total storage volume. The forebay volume is part of the required volume and is not an additional volume requirement.

D. Size the water quality basin for proper discharge of the WQv and the weir for proper discharge of events up to the design check discharge according to Section 1117.4.1. Ensure that the water surface elevations created by the basin are considered in the design of the upstream drainage system.

E. Provide anti-seep collars for the outlet pipe according to Section 1117.3.1.2.

The following criteria apply when designing a retention basin:

A. Place channel protection (RCP or Tied Concrete Block Mat) at the entrance of the basin to minimize erosion and sediment resuspension.

B. Use side slopes of 4:1 (max).

C. Use a length to width ratio of at least 3:1 to prevent short-circuiting.

D. Furnish a trash rack at the outlet structure.

E. The underlying soils should be compacted to prevent infiltration of the permanent pool or an impervious liner should be used.

F. Consider vehicle access to the basin for periodic maintenance.

G. Retention basin must be greater than 10,000 feet from a municipal airport runway.

H. Vegetate the sides of the basin with Item 670 Slope Erosion Protection.

I. Embankment work to create the impoundment will be constructed and paid for as Item 203 Embankment, Using Natural Soils, 703.16.A.

J. Furnish a Water Quality Basin, Retention per 1117.4.1.

K. Label the location and EDA treatment credit on the Project Site Plan for each retention basin on the project.

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1117.4.1 Water Quality Basin and Weir

A retention basin outlet structure is designed similar to the outlet structure for a detention basin. The difference is that the EDv (75% of the WQv) should be discharged out of the basin in 24 hours or more. No more than 50% of the EDv should be released from the detention basin in less than one-third of that 24 hour drain time. The outlet structures are of a similar type, except the openings will be set at a high enough elevation to maintain at least 75% of the WQv in the permanent pool (see standard construction drawing WQ-1.1). The catch basin and riser pipe is paid for as Item 611, Water Quality Basin, Retention.

1117.5 Bioretention Cell

A Bioretention Cell consists of a depressed area that allows shallow ponding and treatment of storm water runoff by evapotranspiration and filtration through an engineered soil (bioretention planting soil). As storm water runoff percolates through the bioretention planting soil, sediment and other pollutants are filtered. An underlying perforated underdrain captures the treated storm water runoff and carries it to an outlet. Vegetation assists in maintaining ongoing performance of bioretention cells.

Furnish Item 659 Seeding and Mulching for the vegetation of the Bioretention Cell. Cover this area with Item 671, Erosion Control Mat. Do not furnish any 659 Commercial Fertilizer or 659 lime in the Bioretention Cell. Other shrubs or plantings may be furnished in the Bioretention Cell with permission of OHE.

The water table or bedrock must be at least 1 foot below the invert (excavated depth) of the bioretention cell.

A bioretention cell is sized to treat the WQV by allowing that volume of runoff to percolate through the bioretention planting soil. Storm water runoff greater than the WQV is allowed to bypass treatment through an overflow structure. Treatment credit is given to the total area within the right-of-way draining to the most downstream part of the bioretention cell.

There are two configurations of bioretention cells:

Level bioretention cell in an open area with grassed side slopes (Figure 1117-8) Sloped bioretention cell within a grassed ditch (Figure 1117-8)

1117.5.1 Level bioretention cell in an open area with grassed side slopes

Furnish pretreatment of the storm water prior to entering the bioretention cell by one of the following methods:

A. For sheet flows from impervious areas, the runoff shall flow through a minimum of 5 feet (preferably 15 feet) of grassed filter strip with side slopes no steeper than 3:1.

B. For concentrated flows (from a pipe, open channel, or curb cut), the runoff must flow through either a grassed swale at least 20 feet in length or a forebay sized to capture 10% of the WQV.

Furnish a raised catch basin per Figure 1117-8 to allow the design check discharge to bypass the bioretention cell. The design check discharge shall be determined per Section 1117.3.3. Ensure the elevation of the overflow outlet in the raised catch basin is 12 inches above the surface elevation of the bioretention cell. Ensure that the raised catch basin is located outside of the clear zone.1117.5.2 Sloped bioretention cell within a grassed ditch

Furnish pretreatment of the storm water prior to entering the bioretention cell by one of the following methods:

A. For sheet flows from impervious areas, the runoff shall flow through a minimum of 5 feet (preferably 15 feet) of grassed filter strip with side slopes no steeper than 3:1.

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B. For concentrated flows (from a pipe, open channel, or curb cut), the runoff must flow through either a grassed swale at least 20 feet in length or a forebay sized to capture 10% of the WQV.

Furnish an earth dike covered with item 601 Tied Concrete Block Mat Type 1 per Figure 1117-8 to allow the design check discharge to bypass the bioretention cell. The design check discharge shall be determined per Section 1102 for the appropriate design storm of the ditch. The dike shall be 1V:6H or flatter and pond water to a maximum depth of 12 inches. A dike shall be installed at every 1 foot of elevation drop along the longitudinal slope of a linear bioretention cell. For example, if a ditch line is at a 1% slope, a dike would be installed every 100 feet along its length to promote temporary ponding and filtration through the bioretention planting soil.

1117.5.3 Bioretention Cell Design Procedure

Use the following procedure for the design of a bioretention cell or follow the bioretention design found in the Ohio Department of Natural Resources’ Rainwater and Land Development Manual:

A. Determine the total impervious tributary area to the bioretention cell: ATRIB,IMP. Include impervious area within and outside of the right-of-way; however treatment credit is only given to the area within the right-of-way. Consider all area within existing right-of-way to be impervious, even if the area is grassed.

B. The minimum bioretention cell surface area is 5% of the total impervious tributary area.

ABIO = ATRIB,IMP x 5%

C. Choose one of the two configurations of bioretention cells and follow the appropriate pretreatment and overflow requirements described in Section 1117.5.1 and 1117.5.2.

D. Ensure a maximum depth of 12 inches measured from the Final Grade of the bioretention cell to the outlet structure (riser pipe, raised catch basin, weir, or check dam).

E. In addition to the pretreatment required where concentrated flow enters the bioretention cell, limit the incoming velocity to 1 fps or less for the Water Quality Flow (WQF) to protect the bioretention cell from erosion. Calculate the WQF per Section 1115.5 at the point of concentrated flow. Increase the pipe size, widen the open channel, increase the curb opening to the bioretention cell, or provide energy dissipation to limit the velocity to 1 fps or less. For Curb Cuts, assume all the WQv is captured by the curb opening and use the height of the curb and the opening width to calculate the area.

F. Do not place a bioretention cell where the required hydraulic design flows (i.e. 2 year event, 5 year event,10 year event, or higher) have an Allowable Shear Stress higher than 1 psf or velocity higher than 5 fps

G. Furnish the bioretention cell layers as shown in Figure 1117-8.

1. Bioretention Planting Soil Layer: Furnish 30 inches of bioretention planting soil (plan note WQ101). When planting shrubs or trees, ensure the bioretention planting soil layer extends at least 4 inches below the lowest root ball.

2. Filter Layer: Furnish 3 inches of Fine Aggregate per CMS 703.20 directly below the bioretention planting soil layer. Furnish 3 inches of Coarse Aggregate size No. 78 per CMS 703.20 directly below the Fine Aggregate layer.

3. Gravel Layer for Underdrain: Furnish 12 inches of Coarse Aggregate size No. 57 per CMS 703.20 directly below the No. 78 aggregate layer. A minimum of 3 inches of No. 57 aggregate shall be provided above and below any underdrain pipes.

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11-52 April 2017

H. For the bioretention planting soil, specify 10% excess planting mix volume to account for expected settling of the uncompacted soil. Show final expected soil elevations on the plans, but allow contractor to place bioretention planting soil 3 inches above elevations shown on plans, as described in Plan Note W101 Bioretention Cell(s).

I. Furnish one 4 inch diameter perforated PVC pipe underdrain per CMS 605 along the length of the bioretention cell. Furnish one underdrain at the center for widths 20 feet or smaller. For all other widths calculate the number of underdrains required by dividing the width by 20 and rounding up to the next whole number. Space these underdrains equally around the center with a minimum distance of 5 feet from the outside edge.

J. Furnish a 4 inch diameter PVC observation well/cleanout port in accordance to Figure 1117-8 for every run of underdrain at an interval of 100 feet.

K. Outlet the underdrain by combining all underdrains into a single 6 inch type C Item 611 pipe. Furnish this pipe with a positive outlet either into a drainage structure that is part of the drainage design or on a slope with Item 611 precast concrete outlet. Show underdrain connection to outlet in the plans.

L. For bioretention cells planted with grass, include temporary erosion control mat Type A, B, C, or E per CMS 671 over the surface of all bioretention planting soil. Specify the mat type on the plan sheets.

M. For non-grass bioretention cells that include shrubs or trees, furnish a 3 inch layer of wood fiber mulch per CMS 659.15 above the bioretention planting soil.

N. Label the location and EDA treatment credit on the Project Site Plan for each bioretention cell on the project.

O. PAY ITEMS:

203 Excavation APP cu yd601 Bioretention Cell cu yd601 Tied Concrete Block Mat sq yd605 Underdrain APP, (includes observation wells, fittings, and couplers as specified)611 Outlet Pipe659 Seeding and Mulching sq yd671 Erosion Control Mats sq yd

1117.6 Infiltration

Infiltration techniques treat storm water through the interaction of a filtering substrate that consists of soil, sand, or gravel. This technique discharges the treated storm water into the ground water rather than into surface waters. Typically, infiltration practices are only suitable when Hydrologic Soil Group (HSG) Type A soils or, in some cases, HSG Type B soils exist.

Infiltration methods require an extensive investigation of the existing soils and geology to ensure success. The investigation should begin with a preliminary soil evaluation of the project site early in the design process (PDP Preliminary Engineering Phase). In-situ testing is not anticipated during the preliminary evaluation process.

Use available soil and geology data found in the Soil and Water Conservation maps, United States Geological Survey (USGS), adjacent projects, or estimations from a geotechnical engineer. National Resources Conservation Service’s Web Soil Survey website may also provide soil and geology information.

Material property tables for infiltration, permeability, and porosity have been provided for the preliminary evaluation (Tables 1117-5 & 1117-6).

Drainage Design Procedures

April 2017 11-53

If the preliminary evaluation yields favorable results, perform a more detailed evaluation. The detailed evaluation will require a geotechnical investigation of the underlying soils and geology. Soil borings should be performed to a maximum depth of 20 feet (or refusal) with samples taken every 5 feet for laboratory testing. The number and location of soil borings should correspond with the approximate size (as determined in the preliminary evaluation) of the infiltration BMP and should be recommended by the geotechnical engineer.

If the detailed evaluation yields favorable results, the ground water depth must be verified. The geotechnical engineer shall provide the seasonal high ground water depth. In some cases, observation wells may be installed and static water levels may be observed over a dry and wet season for verification. The infiltration and permeability rate of the soil shall be tested in the detailed soil evaluation at the discretion of the geotechnical engineer. In some cases, insitu testing at the proposed location of the infiltration BMP may be required.

The following criteria apply to infiltration methods and must be met to be considered a feasible alternative:

A. Design using the WQv as per Section 1115.

B. Do not place infiltration BMP where snow may be stored.

C. The appropriate soil type must be present:

1. Infiltration (the rate at which water enters into the soil from the surface) must be greater than 0.50 in/hr and no greater than 2.4 in/hr.

2. Soils must have less than 30% clay or 40% of clay and silt combined.

D. The invert of the structure must be at least 4 feet above the seasonal high water table and any impervious layer.

E. Infiltration techniques are not suitable on fill soil, compacted soil, or steep slopes (greater than 4:1). Consideration should be given to the long term impacts upon hillside stability if applicable.

F. Pretreatment shall be provided to remove large debris, trash and suspended sediment to extend the service life. An example of pretreatment includes providing vegetated ditches prior to flow entering the infiltration facility.

1117.6.1 Infiltration Trench

An infiltration trench is an excavated trench that has been lined with a geotextile fabric and backfilled with aggregate. The storm water is filtered through the aggregate and is stored within the pore volume of the backfill material. It is allowed to percolate through the sides and bottom of the trench. The drawdown time of the WQv is 24 hours or more.

Design of an infiltration trench must follow the criteria in the Ohio Department of Natural Resources’ Rainwater and Land Development Manual: http://epa.ohio.gov/dsw/storm/technical_guidance.aspx

The following criteria apply when designing an infiltration trench:

A. Furnish a 6 inch layer of Coarse Aggregate No. 57 or 67 conforming to CMS 703.20 per CMS 601.10 on the top of the trench.

B. Furnish Coarse Aggregate No. 1 or 2 conforming to CMS 703.20 within the infiltration trench.

C. Pretreatment using vegetation shall be provided to ensure longevity of the infiltration trench.

D. An observation well shall be provided to facilitate ground water level inspection.

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11-54 April 2017

E. Locate the infiltration trench at least 1,000 feet from any municipal water supply well and at least 100 feet from any private well, septic tank, or field tile drains.

F. Ensure the bottom of the trench is below the frost line (2.5 feet)

G. Furnish an infiltration trench as Item 601 – Infiltration Trench.

H. Label the location and EDA treatment credit on the Project Site Plan for each infiltration trench on the project.

1117.6.2 Infiltration Basin

An infiltration basin is an open surface pond that uses infiltration into the ground as the release mechanism. It is designed to store the WQv.

Depending on the soil permeability, it may be used to treat from 5 to 50 acres. Lower permeable soils may require an underdrain system as an additional outlet. The drawdown time of the WQv should be between 24-48 hours.

Use the following procedure for the design of an infiltration basin:

A. Calculate the WQv per Section 1115.4.

B. Determine the invert area of the infiltration basin using the following equation:

A = (WQv * S.F. * 12)/(k * t)

Where:A = area of invert of the basin (Acres)WQv = Water Quality Volume (see section 1115) (Acre-feet)S.F. = Safety Factor of 1.5k = Infiltration Rate (in/hr) (table 1117-6)t = Drawdown time of 48 hours

Table 1117-5

NRCS Soil Type (from soil maps) HSG Classification Rate (k) (in/hr)

Sand A 8.0Loamy Sand A 2.0Sandy Loam B 1.0

Loam B 0.5Silt Loam C 0.25

Sandy Clay Loam C 0.15Clay Loam & Silty Clay Loam D < 0.09

Clays D < 0.05Infiltration Rate (k)

From Urban Runoff Quality Management WEF Manual of Practice No. 23, 1998, published jointly by the WEF and ASCE, chapter five

C. Use a length to width ratio of 3:1.

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April 2017 11-55

D. Determine the required depth of the infiltration basin using following equation:

D = WQv/A

Where:A = area of invert of the basin (Acres)WQv = Water Quality Volume (Ac-ft)D = Required depth of the basin (ft)

E. Allow for 1 foot (min) freeboard above the WQv.

F. Calculate the Design Check Peak Discharge per Section 1117.3.3.

G. Furnish bypass or overflow for the design check discharge.

The following criteria apply when designing an infiltration basin:

A. Use an energy dissipater at the inlet.

B. Vegetate the sides of the basin with Item 670 Slope Erosion Protection.

C. Furnish a 6 inch layer of Coarse Aggregate No. 57 or 67 conforming to CMS 703.20 per CMS 601.10 on the bottom of the basin.

D. Use side slopes of 4:1 (max).

E. Consider vehicle access to the basin for periodic maintenance.

F. Locate basin at least 1,000 feet from any municipal water supply well and at least 100 feet from any private well, septic tank, or drain field.

G. Furnish 10 feet or less width between 4 inch underdrain laterals (if used in the design).

H. Do not locate the basin where infiltrating ground water may adversely impact slope stability.

I. Ensure the invert of any underdrain in the basin is below the frost line (2.5 feet).

J. Embankment work to create the impoundment will be constructed and paid for as Item 203 Embankment, Using Natural Soils, 703.16.A.

K. Label the location and EDA treatment credit on the Project Site Plan for each infiltration basin on the project.

1117.7 Constructed Wetlands

Constructed Wetlands treat storm water through bio-retention. They are depressed, heavily planted areas that are designed to maintain a dry weather flow depth ranging between 0.5 to 2 feet. The surface area required for a wetland is usually quite large due to the limited allowable depth. The area is usually on the magnitude of 1% of the entire drainage area. They are designed in a similar manner as a retention basin. The wetland is sized to provide storage for the WQv for a time frame of at least 24 hours (above the permanent pool) while providing a bypass or overflow for larger design check discharge (see section 1117.3.3). The water depth should be maintained by an outlet structure capable of providing the required water depth with the provision of a one foot freeboard. The following criteria apply when designing a Constructed Wetland:

A. Do not place on a steep or unstable slope or at a location, which could induce short-term or long-term instability.

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11-56 April 2017

B. Constructed Wetlands must be greater than 10,000 feet from a municipal airport runway.

C. Base flow must be present to maintain the constant water depth (such as ground water).

D. Furnish a forebay that is 7% of the total required volume at a depth between 3-6 feet to settle out sediments.

E. Furnish side slopes of 4:1 (max).

F. Consider access for maintenance to the forebay and the outlet structure.

G. Vegetate the sides and bottom with grassH. Furnish an impervious liner. Use a compacted clay bottom or a geotextile fabric to prevent infiltration

of the storm water.

I. Furnish a length to width ratio of 3:1 (min) to prevent short-circuiting.

J. Label the location and EDA treatment credit on the Project Site Plan for each constructed wetland on the project.

1117.8 Stream Grade Control

Stream grade control structures are structures installed on the upstream and downstream end of a culvert at a stream crossing to promote stream protection. They provide a grade control in a stream to prevent downcutting of the stream bed. The following are Stream Grade Control structures:

Concrete aprons shown in Section 1106.3. Three sided culverts with paved Inverts Three sided culverts with bed rock inverts

Stream grade control structures provide quantity treatment, but not quality treatment. Therefore, stream grade control structures must be paired with a post-construction BMP that provides quality treatment. Only those portions of a project within existing and/or new permanent right-of-way that drain to a stream grade control structure receive quantity treatment credit. Stream grade control structures are only an appropriate post-construction BMP when installed within a Waters of the United States, and associated with sites that acquire a permit from the Army Corps of Engineers for stream impacts.

Label the location and EDA treatment credit on the Project Site Plan for each stream grade control structure on the project.

1118 Bridge Hydraulics

1118.1 General

Bridge structural design requirements are found in the Bridge Design Manual while hydraulic design criteria are governed by this manual. When submitting hydraulic design calculations, flood hazard evaluations, hydrology and hydraulic reports, and scour evaluations submit to the Office of Hydraulic Engineering.

1118.2 Hydrology and Hydraulics (H&H) Report

The H&H report is required as part of the Structure Type Study.

A. A small scale area plan showing: approximate location of all stream cross sections used for the hydraulic analysis; an accurate waterway alignment at least 500 feet each way from the structure; and the alignment of the proposed and present highways, taken from actual surveys.

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April 2017 11-57

B. Provide a profile along the centerline of highway so that the overflow section may be computed. This profile should extend along the approach fill to an elevation well above high water. If there are bridges or large culverts located within 1000 feet upstream or downstream from the proposed bridge, show stream cross sections including the structure and roadway profiles of the overflow sections of the structures. These may be used as a guide in establishing the waterway requirements of the proposed structure.

1118.2.1 Analysis

The H&H analysis is performed using the design year as discussed in section 1004.2 of this manual along with the 100 year and 500 year frequencies. A step backwater calculation is computed for each frequency. A one-dimensional step backwater software (example: HEC-RAS) is acceptable. In some cases a two-dimensional step backwater method may be necessary at the direction of the Department. Include the following items in the H&H analysis:

A. Hydrology calculations or origin of discharge frequencies used in the analysis. Include the drainage area in square miles.

B. Input and output data including electronic program files. If using the HEC-RAS computer program, refer to the HEC-RAS Help Applications Guide for the “Multiple Plans” file structure.

C. Plan view of stream with cross sections identified. Include enough cross sections to properly model the existing and proposed stream as required.

D. Color photographs of the upstream channel, downstream channel, and the bridge opening location.

E. Computations for existing and proposed conditions.

1118.2.2 Narrative

The Narrative is a written discussion the hydraulic adequacy for both the design year and 100 year frequency discharges. The narrative includes the rationale used to determine the proposed structure size and it is supported by an analysis of design alternatives.

Include the following in the narrative:

A. Capital costs and risk as part of the discussion. “Risk” is defined as the consequences attributable to a flood plain encroachment.

B. A statement as to whether or not the structure is located in a flood insurance study. Identify the Flood Insurance map showing the project location, with any designated floodway information or elevations.

C. High water data from local residents and observed high water marks including their locations.

D. Approximate Flood Peak Discharge Frequency of roadway overtopping.

E. A Flood Hazard Evaluation (see 1005.2)

F. Description of the bridge deck drainage. Indicate how the surface water will be collected and discharged. Include any scupper catch basin locations.

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11-58 April 2017

1100 Drainage Design Procedures – List of Figures

April 2017

Figure Subject

1101-1 Overland Flow Chart

General Notes for Figures 1101-2 and 1101-3

1101-2 Rainfall Intensity-Frequency-Duration Curves

1101-3 Rainfall Intensity Zone Map

1102-1 Capacity of Grate Catch Basin in a Sump

1102-2 Channel Features

1103-1 Nomograph for Flow in Triangular Channels

1103-2 Capacity of Curb Opening Inlets on Continuous Grade

1103-3 Capacity of Standard Catch Basin Grates in Pavement Sags - Flow Through Grate Opening

1103-4 Capacity of Inlets and Standard Catch Basins in Pavement Sags - Flow Through Curb Opening

1104-1 Type F, Broken Back Detail

1105-1 Classification of Flow in Culverts

1105-2 Corrugated Metal Pipe Sizes and "n" Values for Type A Conduits

1105-3 Example Bankfull Discharge Culvert Design

1106-1 End Treatment Grading Detail

1106-2 Box Culvert Outlet Detail

1106-3 Box Culvert Inlet Detail

1107-1 Rock Channel Protection at Culvert Storm Sewer Outlets

1112-1 Notice of Intent (NOI) Acreage Calculation Form

1115-1 Water Quality Cq

1115-2 Post-Construction BMP Treatment

1116-1 Exempt Outfalls

1117-1 Figure Deleted January 2014

1117-2 Manufactured System Detail

1117-3 Vegetated Biofilter Detail

1117-4 Figure Deleted January 2015

1117-5 Figure Deleted July 2015

1100 Drainage Design Procedures – List of Figures

April 2017

1117-6 Extended Detention Basin Example

1117-7 Retention Basin Example

1117-8 Bioretention Cell Example

1117-9 Figure Deleted January 2016

1117-10 Infiltration Basin Example

1117-11 Anti-Seep Collars

General Notes – Figures 1101-2 through 1101-3

The Rainfall Intensity-Duration-Frequency (IDF) curves are based upon precipitation data obtained from the National Oceanic and Atmospheric Administration (NOAA) Atlas 14. The precipitation data was collected between 4/1863 to12/2000.

Rainfall depth varies across the State with more rainfall depth present in the Southwest portion of the state and gradually decreasing towards the Northeast. IDF curves were developed for 4 regions across the State to simplify hydraulic design. The regions were determined by normalizing contours created from NOAA precipitation GIS data from the 10 year, 60 minute duration.

Federal Highway Administration Hydraulic Engineering Circular No. 12 Appendix A offers a methodology for converting I-D-F data points to an equation of the general form:

i= a/(t+b)^c Where: i = rainfall intensity (inches/hour)t = time of concentration (minutes)a = constantb = constantc = constant

Figure 1101-2 can be expressed using the above general equation utilizing the constants shown below.

Intensity Zone (Figure 1101-3) Frequency (Years)

Constant "a"

Constant "b"

Constant "c"

2 46.184 9.000 0.859 5 56.985 10.250 0.851A 10 64.167 11.000 0.842

25 66.528 11.000 0.811 50 65.702 10.750 0.782 100 64.489 10.500 0.754

2 47.987 9.000 0.859 5 60.684 10.500 0.858B 10 73.126 12.000 0.863

25 75.841 12.000 0.833 50 65.621 10.000 0.781 100 85.047 13.250 0.806

2 56.299 10.000 0.876 5 67.933 11.000 0.869C 10 84.550 13.000 0.882

25 95.736 14.000 0.871 50 96.783 14.000 0.850 100 80.436 11.500 0.794

2 57.448 10.000 0.876 5 67.933 11.000 0.869D 10 79.192 12.000 0.864

25 87.886 12.750 0.849 50 95.169 13.500 0.839 100 91.982 13.000 0.810

For any projects that have begun using the previous Rainfall Intensity-Duration-Frequency (IDF) curves, continue with their use through the completion of the project. The current Rainfall Intensity-Duration-Frequency (IDF) curves should be used at the start for all new projects.

Refer to General Notes ‐ Figures 1101‐2 through 1101‐3

Rainfall Intensity-Frequency-Duration Curves

Revised July 2014

1101-2Reference Section

1101.2.4

0

1

2

3

4

5

6

7

8

10 15 30 60 120 180

INTENSITY

 (IN/H

OUR)

DURATION IN MINUTES

AREA A

2

5

10

25

50

100

Year

0

1

2

3

4

5

6

7

8

10 15 30 60 120 180

INTENSITY

 (IN/H

OUR)

DURATION IN MINUTES

AREA B

2

5

10

25

50

100

Year

0

1

2

3

4

5

6

7

8

10 15 30 60 120 180

INTENSITY

 (IN/H

OUR)

DURATION IN MINUTES

AREA C

2

5

10

25

50

100

Year

0

1

2

3

4

5

6

7

8

10 15 30 60 120 180

INTENSITY

 (IN/H

OUR)

DURATION IN MINUTES

AREA D

2

5

10

25

50

100

Year

Revised July 2014

Rainfall Intensity-Frequency-Duration Curves1101-3

Reference Section1101.2.4

Refer to General Notes ‐ Figures 1101‐2 through 1101‐3

wit

h 4'

bein

g the

minim

um.

18" of 6" rock

wit

hout erosio

n, no rock channel protectio

n

will be requir

ed.)

(Where a strea

m bed

will

wit

hstand the calculated velocit

y

of the

material, by

weig

ht,

will be retain

ed.

Rock siz

e (6

", 12

", 18

") in

dic

ates the square openin

g on

whic

h 85

%

The

width of protectio

n shall be the

width of the head

wall,

20

1816

1412

108

64

0

LENGTH OF PROTECTION

VE

LO

CIT

Y

AT PIP

E

OU

TL

ET - f.p.s.

No Protection

48" Thickness of Type A Rock

or Energy Dissipator

Over 20 f.p.s. use

Energy Dissipator

30" of 12

" rock

36" of 18

" rock

48" of 18

" rock

RO

CK

A A B C

1

2

3

4

72"84"

96"

108"

120"

12"24"63

"48"

06

"Pip

e

Dia

meter or Ris

e

1 2 3 4

NO

TES

LE

GE

ND

TY

PE

40

30

20 10

REFERENCE SECTIONAT CULVERT AND STORM

SEWER OUTLETS 1107.2

1107-1ROCK CHANNEL PROTECTION

January 2008

Reference Section

1112

Area (acres)

Project Earth Disturbing Activities

Contractor Earth Disturbing ActivitiesField Office:

Enter 0.125 for Type A; 0.25 for Type B; or 1.00 for Type C

Batch Plant: Yes = 2.0; No = 0

Off-Project Waste / Borrow Pit:

Add 1.0 acre per 15,000 CY of waste or borrow

Miscellaneous Other Off-Project Areas:

Off-Project staging areas, stock yards, etc.

Contractor Earth Disturbing Activities Subtotal

Total Earth Disturbing Activities (add Project EDA and Contractor EDA) TOTAL

NOI Earth Disturbing Activities (see below to determine value) TOTAL

Contractor Earth Disturbing Activities:

Batch Plant - It is assumed that a typical batch plant would occupy 2 acres of ground. The designer should

investigate the location of the project relative to existing plants, facilities, etc. to estimate whether a batch plant

might be used by the Contractor. This is not needed for existing plants, it is only for plants set up for the specific

project.

NOTICE OF INTENT (NOI) ACREAGE CALCULATION FORM1112-1

Field Office - These sizes were determined with regard to size of the trailer, parking, and some stock area for

equipment and materials.

Project Earth Disturbing Activities - Enter the area of permanent earth disturbing activities directly related to project

activities. Earth disturbing activity is defined as any activity that exposes bare ground or an erodible material to

storm water and anywhere Item 659 Seeding, SS 870 Seeding, Item 660 Sodding, or SS 870 Sodding is being

furnished.

If the project is a Routine Maintenance Project, an NOI is not required. (See Section

1112)

NOI Earth Disturbing Activities - This is the combined Project and Contractor Earth Disturbed Area. Based on

project conditions and activities, some flexibility in the area calculation should be provided to avoid the possibility of

the estimated work being less than the actual work. This scenario would require submittal of an NOI for projects

originally calculated to be less than one acre during construction.

A Routine Maintenance Project consists of activities that do not change the line, grade, or hydraulic capacity of the

existing condition and has less than 5 acres of earth disturbing activities (see section 1112.2).

For projects with an estimated NOI EDA less than one acre: No NOI is required. For projects with an estimated

NOI EDA of one or more acre, but less than 4.9 acres, use 4.9 acres. For projects with an estimated NOI EDA

greater than 4.9 acres, use the sum of the Project and Contractor Earth Disturbed Areas.

Off-Project Waste / Borrow - The specified estimation is based on approximately 10 feet of depth or fill over 1

acre. The designer may choose a different value based on knowledge of the project area, bedrock elevations,

previous projects, etc. Consideration should be given for grindings, as well. (10ft. x 43560 s.f. / 27 = 16,133 c.y. ~

15,000 c.y.)

0

0.1

0.2

0.3

0.4

0.5

0.6

0.7

0.8

0.9

1

0 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9 1

Impervious ratio

Cq

WATER QUALITY Cq1115-1

REFERENCE SECTION1115

January 2008

REFERENCE SECTIONMANUFACTURED SYSTEM DETAIL

1117-2

JULY 2011

1117

PLAN VIEW

NOT TO SCALE

OFFLINE MANUFACTURED SYSTEM

SIZED PER 1117.2

INFLOW TRUNK SEWER OUTFLOW TRUNK SEWER

MANHOLE NO. 3

W/BASE DIAMETER

PER SECTION 1117.

SOME SYSTEMS REQUIRE

TWO SMALLER MANHOLES

RATHER THAN ONE LARGE

MANHOLE.

8"

DIVERSION WEIR

RESERVED AREA FOR

A 45 DEGREE ANGLE.

LOCATED UP TO

SEWER CAN BE

OUTFLOW TRUNK

RE

SE

RV

ED

WID

TH

PE

R 1

117

1 of 13

July 2015

EXTENDED DETENTION BASIN

EXAMPLE

1117-6 REFERENCE SECTION

1117

Given:

• Total Tributary Area = 7.5 ac

o Tributary Area within Existing R/W = 7.2 ac

o Tributary Area, Impervious, Outside of R/W = 0.3 ac

o Tributary Area, Pervious, Outside of R/W = 0.0 ac

o Tributary Area, Pavement and Paved Shoulders = 1.5 ac

o Tributary Area, Berms and Slopes 4:1 or Flatter = 6.0 ac

• Rainfall Area B

• Time of Concentration, tC = 25 min (calculation shown in this example)

Calculate the water quality volume WQV:

• WQV = (P*A*Cq)/12

• P = 0.75 in

• A = 7.5 ac

• Cq = 0.858i3 – 0.78i2 + 0.774i + 0.04

o i = fraction impervious

o The area within existing ODOT right-of-way is considered impervious area for the

purpose of post-construction BMP design considerations. (L&D Vol 2, Sec. 1115.6.1)

o i = �.�����.��

�.�� = 1.0

• Cq = 0.858*13 - 0.78*12 + 0.774*1 + 0.04 = 0.892

• Per L&D Vol. 2, Section 1115.6.1, consider all area within existing right-of-way to be impervious

with a runoff coefficient of 0.90. Therefore, Cq = 0.9

• WQV = (0.75 in * 7.5 ac * 0.9) / 12

• WQV = 0.422 ac-ft

Calculate the minimum detention basin volume, forebay volume, and micropool volume:

• Minimum basin volume = WQV * 1.20 (due to 20% increase)

= WQV*1.2 = 0.422 ac-ft *1.2 = 0.506 ac-ft

• 10% WQV for forebay volume, 10% * 0.422 ac-ft = 0.042 ac-ft

• 10% WQV for micropool volume, 10% * 0.422ac-ft = 0.042 ac-ft

Layout a detention basin configuration that meets the following requirements:

• Forebay volume below the lowest outlet elevation at upstream end of the basin

• Micropool volume below the lowest water quality outlet invert elevation at the downstream

end of the basin

• Maximum 4:1 side slopes

• Include provisions for vehicle access

2 of 13

July 2015

EXTENDED DETENTION BASIN

EXAMPLE (C0NTINUED)

1117-6 REFERENCE SECTION

1117

Detention Basin Plan View:

Detention Basin Profile View:

Forebay:

• The forebay volume is the volume stored upstream of the low flow channel. The volume in the

forebay is held in a permanent pool, and is unable to flow downstream towards the outlet. The

purpose of the forebay is to allow runoff to slow enough for coarse sediment to settle out. This

improves performance and reduces the maintenance burden by concentrating sediment buildup

in one location designed for maintenance access.

• Forebay volume must be greater than or equal to 0.042 ac-ft.

• Forebay depth = 795.5 – 793.5 = 2 ft

• Forebay bottom area = 25 ft * 18 ft = 450 ft2

• Forebay top area = 41 ft * 34 ft = 1,394 ft2

• Forebay volume = (450 ft2 + 1,394 ft2) / 2 * 2ft / 43,560 = 0.042 ac-ft

• 0.042 ac-ft is equal to the 0.042 ac-ft requirement: Acceptable

3 of 13

July 2015

EXTENDED DETENTION BASIN

EXAMPLE (C0NTINUED)

1117-6 REFERENCE SECTION

1117

Micropool:

• The micropool volume is the volume that is stored below the lowest invert elevation of the

lowest water quality outlet. The purpose of the micropool is to slow runoff draining towards the

outlet structure, promote sediment settling below the outlet structure, and allow use of a non-

clogging outlet. This improves performance and reduces clogging and maintenance.

• Micropool volume must be greater than or equal to 0.042 ac-ft.

• Micropool depth = 795.5 – 793.5 = 2 ft

• Micropool bottom area = 25 ft * 20 ft = 500 ft2

• Micropool top area = 41 ft * 36 ft = 1,476 ft2

• Micropool volume = (500 ft2 + 1,476 ft2) / 2 * 2ft / 43,560 = 0.045 ac-ft

• 0.045 ac-ft is greater than 0.042 ac-ft requirement: Acceptable

Water Quality Volume (WQV) Storage:

• The WQV must be fully stored above the lowest water quality outlet elevation.

• The lowest water quality outlet is at an elevation of 795.5 ft.

• The WQV (0.422 ac-ft) must be stored between 795.5 ft and catch basin overflow.

4 of 13

July 2015

EXTENDED DETENTION BASIN

EXAMPLE (C0NTINUED)

1117-6 REFERENCE SECTION

1117

Stage (Elevation) vs. Volume Curve:

The graph shows that the full WQV is stored between 799.00 and 795.50 ft in the detention

basin. The forebay and micropool have been excluded from this stage vs. volume graph since

the volume associated with the forebay and micropool is constantly standing water.

5 of 13

July 2015

EXTENDED DETENTION BASIN

EXAMPLE (C0NTINUED)

1117-6 REFERENCE SECTION

1117

Design the Detention Basin Water Quality Outlet:

• The minimum discharge time of the WQV is 48 hours with no more than 50% of the WQV being

released from the detention basin in the first one-third of the 48 hour drain time.

• WQV = 0.422 ac-ft; must take 48 hours or longer to drain

• 50% or less of the WQV (i.e. 0.211 ac-ft) must be drained in 16 hours.

• Choose eight 0.5 inch diameter circular orifices at 795.50 ft and eight 0.5 inch diameter circular

orifices at 796.50 ft.

• Calculate the drawdown curve.

o This calculation can be done by hand by creating a stage vs. discharge table and

interpolating between values, but it is generally easier to use a model to simulate runoff

through a detention basin such as PondPack or HydroCAD.

• Do not route a design storm hydrograph through a detention basin to determine the drawdown

curve. Start the simulation with the water surface at a level equivalent to the WQV storage (for this

example, at an elevation of 799.00). Then allow the pooled water filling the WQV to drain by gravity

out of the water quality outlet structure. Include all detention basin outlets that would affect this

drawdown curve. Include any downstream constraints such as tailwater or limiting conveyance

downstream. For this example, there is no tailwater and there is a free discharge from the

detention basin.

6 of 13

July 2015

EXTENDED DETENTION BASIN

EXAMPLE (C0NTINUED)

1117-6 REFERENCE SECTION

1117

Modeled Drawdown Curve using Pond Pack:

• The graph shows that it takes longer than 48 hours to drain the WQV (0.422 ac-ft); therefore, it is

acceptable.

• The graph shows that it takes 16 hours to drain one half of the WQV (0.211 ac-ft); therefore, it is

acceptable.

Size the Primary Detention Basin Outlet:

• There are three main parts of a typical extended detention basin discharge structure:

o Water quality outlet(s)

o Primary outlet

o Overflow weir

7 of 13

July 2015

EXTENDED DETENTION BASIN

EXAMPLE (C0NTINUED)

1117-6 REFERENCE SECTION

1117

• The primary detention basin outlet normally consists of a catch basin grate and the conduit that

conveys discharges from the detention basin during all but the least frequent precipitation events.

• The primary outlet should be sized to convey the 10-year design storm.

ODOT Water Quality Catch Basin Detail (WQ-1.1):

Determine the 10-year peak flow rate:

• For the purposes of post-construction BMP calculations, all existing right-of-way is to be

considered impervious. For the purpose of general conveyance sizing, runoff coefficients should

be calculated using Table 1101-2 in ODOT’s L&D Vol. 2.

• Q = CiA

8 of 13

July 2015

EXTENDED DETENTION BASIN

EXAMPLE (C0NTINUED)

1117-6 REFERENCE SECTION

1117

Calculate the weighted C value:

1.5 acres of tributary area are pavement and paved shoulders: C = 0.9

6.0 acres of tributary area are berms and slopes 4:1 or flatter: C = 0.5

Cweighted = �.��∗�. ��.���∗�.

�.�� = 0.58

Determine the precipitation intensity:

Rainfall Area B

tC = 25 min

(The time of concentration is given in this example as 25 minutes because there is

significant overland flow over grassed area. The time of concentration should be

calculated for each site based on the site-specific flow path. 25 minutes would likely be

too high of a value if the detention basin were receiving flow from a piped system. See

the time of concentration calculations below.)

L&D Vol. 2, Figure 1101-2: Area B, 10-year frequency, 25 min tC: i = 3.4 in/hr

• Q = 0.58 * 3.4 in/hr * 7.5 ac = 14.79 cfs

Time of Concentration (tC) Calculations:

o tC = Time of overland flow (tO) + Time of shallow concentrated flow (tS) + Time of channel

flow (tC)

o Overland Flow (tO)

� tO = �,���.��������/�

��/�

� C = Runoff Coefficient (0.58 for this example)

� L = Distance to most remote location in drainage in feet (max. 300 ft.) (200 ft. in this

example)

� s = Overland slope (percent) (0.33% in this example)

� tO = �,���.���.��������/�

�.�/� = 19.16 minutes

o Shallow Concentrated Flow (tS)

� VS = Velocity of shallow concentrated flow (ft/sec) = 3.281ks0.5

� k = Intercept Coefficient (L&D Table 1101-1) = (0.457 in this example)

� s = Overland slope (percent) (0.33% in this example)

� VS = 3.281 * 0.457 * 0.330.5 = 0.86 ft/sec

� Length of shallow concentrated flow = 200 ft.

� tS = 200 ft. / 0.86 ft/sec = 233 sec = 3.88 minutes

9 of 13

July 2015

EXTENDED DETENTION BASIN

EXAMPLE (C0NTINUED)

1117-6 REFERENCE SECTION

1117

o Channel Flow (tC)

� Manning’s Equation: V = �.� ��/���/�

�

� V = velocity in the channel (ft/sec)

� r = hydraulic radius (0.69 ft. in this example)

� s = channel slope (0.01 ft/ft in this example)

� n = Manning’s Roughness Coefficient (L&D Vol. 2, Table 1102-3) (0.03 in this

example)

� V = �.� ∗�.� �/�∗�.���/�

�.� = 3.88 ft/sec

� Channel length = 500 ft. (for this example)

� tC = 500 ft. / 3.88 ft/sec = 129 sec. = 2.15 minutes

o tC = tO + tS + tC = 19.16 + 3.88 + 2.15 = 25.19 minutes. Use tC = 25 minutes

Size the primary detention basin discharge conduit:

• The discharge conduit must be large enough to convey the 10-year design storm, keeping the

maximum hydraulic grade line within the crown of the pipe.

• This example has the following conduit characteristics:

o Conduit slope = 0.005 ft/ft

o No Tailwater; free discharge

o Pipe Roughness Coefficient = 0.015 (L&D Vol. 2, Section 1104.4.5)

• The minimum conduit size that conveys the 10-year peak flow (14.79 cfs) with the given

characteristics is a 24-inch diameter pipe.

Set the catch basin grate elevation:

• The WQV fills the detention basin to an elevation of 799.0 ft. At water surface elevations of

799.0 ft and below, all discharge should pass through the water quality outlet. (In this example,

the water quality outlet is the two rings of 0.5 inch orifices at 795.5 ft and 796.5 ft.)

• The ODOT standard water quality catch basin detail (SCD WQ-1.1) calls for either Catch Basin

No. 2-3 or 2-4 depending on the outlet pipe size. Both catch basins have a 6-inch high side inlet

that is either 3 or 4 feet wide depending on the catch basin. See the detail:

10 of 13

July 2015

EXTENDED DETENTION BASIN

EXAMPLE (C0NTINUED)

1117-6 REFERENCE SECTION

1117

ODOT Catch Basin No. 2-3 and No. 2-4:

• However, SCD WQ-1.1 calls for a catch basin used for a detention basin to not have the side inlet

windows. Therefore, side inlets should not be included in a detention basin outlet structure.

• The elevation of the top of the grate should be set at the WQV elevation. Therefore, any volume

above the WQV may discharge into the catch basin through the grate.

o Catch basin grate elevation = 799.0 ft

Set the Overflow Weir Invert Elevation:

• The 10-year peak flow rate (14.79 cfs) should pass fully through the primary discharge.

Therefore, no flow should discharge from the overflow weir until the 10-year flow rate has been

exceeded.

• Set the overflow weir invert elevation just high enough above the catch basin grate such that

the full 10-year peak flow rate is conveyed through the primary discharge.

11 of 13

July 2015

EXTENDED DETENTION BASIN

EXAMPLE (C0NTINUED)

1117-6 REFERENCE SECTION

1117

• For this example, the primary discharge pipe is sized at 24 inches in diameter; therefore, Catch

Basin No. 2-3 is appropriate.

• Catch Basin No. 2-3 has the same grate as Catch Basin No. 2-2B.

• The water quality catch basin has one openings to allow runoff inside; Grate No. 2-2-B.

• Use L&D Vol. 2, Figure 1102-1 to determine the necessary head above a No. 2-2-B grate to pass

the 10-year peak flow rate (14.79 cfs).

• According to Figure 1102-1, 1.25 ft of head is required to pass a flow rate of 14.79 cfs.

• Add the necessary head to the grate elevation (799.0 ft)

o 799.0 ft + 1.25 ft = 800.25 ft

• Set the overflow weir elevation at 800.25 ft.

Size the Emergency Overflow Weir and Set the Top of Basin Elevation:

• L&D Vol. 2, Section 1104.4.2 states that the hydraulic grade line should be checked for the 25-

year storm.

• The 25-year peak flow rate should pass fully through the overflow weir.

• Calculate the peak flow rate:

o 25-year intensity @ tC = 25 min and Rainfall Area B: 3.8 in/hr

o 25-year storm peak flow rate: Q = CiA = 0.58 * 3.8 in/hr * 7.5 ac = 16.53 cfs

• Calculate the required weir length for each design storm flow:

o Overflow weir elevation = 800.25 ft

o Assume a top of detention basin elevation of 800.75 ft.

o Maximum height at overflow weir = 800.75 ft – 800.25 ft = 0.5 ft

o Weir equation: Q = C*L*H1.5

� C = 3

� H = 0.5

� L = ?

o Length of a weir: L = �

�∗��.

o 25-year: L = ��.

∗�.�. = 15.6 ft

• Provide a 16 ft wide overflow weir.

• The top of basin elevation is 800.75 ft.

• The overflow weir length could be reduced by increasing the top of basin elevation. Or the top

of basin elevation can be lowered by increasing the overflow weir length. The 25-year peak flow

rate must fully pass through the overflow weir without overtopping the detention basin.

• Flow rates greater than the 25-year peak flow rate may overtop the detention basin

uncontrolled.

• Provide erosion protection at the overflow weir, to the bottom of the berm, and continuing

downstream if there is erosion potential.

12 of 13

July 2015

EXTENDED DETENTION BASIN

EXAMPLE (C0NTINUED)

1117-6 REFERENCE SECTION

1117

Design Anti-Seep Collars:

• Anti-seep collars reduce the conveyance of flow along pipe bedding, outside of a conduit and

increase the flow path for the seepage of water. This helps protect the berm above the

discharge conduit from a detention basin from internal erosion.

ODOT Standard Drawing WQ-1.2

• Calculate the saturated zone length along the conduit (Ls)

o Ls = Y(Z+4)[1+S/(0.25-S)]

o Y = depth of water during the 10-year storm

o Z = slope of embankment

o S = slope of conduit

• Maximum elevation at 10-year storm = 800.25 ft

• Conduit elevation = 795.0 ft

• Y = 800.25 ft – 795.0 ft = 5.25 ft

• Z = 4

• S = 0.005

• Ls = 5.25(4+4)[1+0.005/(0.25-0.005)] = 42.86 ft

• ΔLs = 0.15*Ls = 0.15 * 42.86 ft = 6.4 ft

13 of 13

July 2015

EXTENDED DETENTION BASIN

EXAMPLE (C0NTINUED)

1117-6 REFERENCE SECTION

1117

• Total Projection: P = W – D

o W = 2ft + 2 ft diameter + 2 ft = 6 ft

o P = 6 ft – 2 ft = 4 ft

• Number of collars = ΔLs / P = 6.4 ft / 4 ft = 1.6

o Minimum of 2 collars per outlet conduit

o Use 2 anti-seep collars

• Place both anti-seep collars in the saturation zone (within 42.86 ft of front edge of berm).

• Spacing between collars: between 10 and 25 feet

Additional Considerations:

• Vegetate the sides of the detention basin with Item 670 Slope Erosion Protection per L&D Vol. 2,

Section 1117.3.1.

• For all open water carriers at each inlet and discharge from the detention basin, check the shear

stress and ensure appropriate lining per L&D Vol. 2, Section 1102.3.2.

• For all culverts that discharge into or out of a detention basin, ensure that appropriate rock

channel protection is included per L&D Vol. 2, Section 1107.2.

• Include calculated detention basin ponding elevations in the calculation of the hydraulic grade

line for the upstream conveyance system per L&D Vol. 2, Section 1104.4.2.

• Attempt to locate structures outside of designated flood plains. If a detention basin encroaches

on a flood plain, follow the flood assessment requirements in L&D Vol. 2 Section 1005.

• Ensure that safety criteria are met in the clear zone per L&D Vol. 1, Section 600.2.

• Ensure that no more than one foot of permanent standing water is located within the clear zone

without barrier protection, per L&D Vol. 1, Section 601.1.1.

• Engage local project stakeholders in potential public safety considerations associated with

detention basins.

• Develop a plan for how regular maintenance will be performed.

o Vehicle access

o Mowing

o Removal of woody vegetation

o Regular unclogging of the water quality outlet

1 of 12

July 2015

RETENTION BASIN EXAMPLE 1117-7

REFERENCE SECTION

1117

Given:

• Total Tributary Area = 7.5 ac

o Tributary Area within Existing R/W = 7.2 ac

o Tributary Area, Impervious, Outside of R/W = 0.3 ac

o Tributary Area, Pervious, Outside of R/W = 0.0 ac

o Tributary Area, Pavement and Paved Shoulders = 1.5 ac

o Tributary Area, Berms and Slopes 4:1 or Flatter = 6.0 ac

• Rainfall Area B

• Time of Concentration, tC = 25 min (calculation shown in this example)

Calculate the water quality volume WQV:

• WQV = (P*A*Cq)/12

• P = 0.75 in

• A = 7.5 ac

• Cq = 0.858i3 – 0.78i2 + 0.774i + 0.04

o i = fraction impervious

o The area within existing ODOT right-of-way is considered impervious area for the

purpose of post-construction BMP design considerations. (L&D Vol 2, Sec. 1115.6.1)

o i = �.�����.��

�.�� = 1.0

• Cq = 0.858*13 - 0.78*12 + 0.774*1 + 0.04 = 0.892

• Per L&D Vol. 2, Section 1115.6.1, consider all area within existing right-of-way to be impervious

with a runoff coefficient of 0.90. Therefore, Cq = 0.9

• WQV = (0.75 in * 7.5 ac * 0.9) / 12

• WQV = 0.422 ac-ft

Calculate the extended detention volume (EDV):

• EDV = WQV * 75% = 0.422 ac-ft * 0.75 = 0.317 ac-ft

Calculate the minimum permanent pool storage volume:

• Minimum permanent pool volume = WQV * 75% = 0.422 ac-ft * 0.75 = 0.317 ac-ft

Layout a retention basin configuration that meets the following requirements:

• Maximum 4:1 side slopes

• Include provisions for vehicle access

• Length to width ration of at least 3:1

• At least 75% of WQV stored in a permanent pool

2 of 12

July 2015

RETENTION BASIN EXAMPLE

(CONTINUED)

1117-7 REFERENCE SECTION

1117

Elevation vs. Volume Table:

Elevation

(feet)

Storage

(acre-feet)

Elevation

(feet)

Storage

(acre-feet)

Elevation

(feet)

Storage

(acre-feet)

793 0 795.4 0.241 797.8 0.66

793.2 0.014 795.6 0.268 798 0.704

793.4 0.029 795.8 0.297 798.2 0.75

793.6 0.046 796 0.327 798.4 0.797

793.8 0.063 796.2 0.359 798.6 0.846

794 0.081 796.4 0.391 798.8 0.897

794.2 0.101 796.6 0.425 799 0.949

794.4 0.121 796.8 0.461 799.2 1.003

794.6 0.143 797 0.498 799.4 1.058

794.8 0.166 797.2 0.536 799.6 1.115

795 0.189 797.4 0.576 799.8 1.174

795.2 0.215 797.6 0.617 800 1.235

793

794

795

796

797

798

799

800

0 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9 1 1.1 1.2 1.3

Ele

va

tio

n (

ft)

Volume (ac-ft)

Elevation vs. Volume

Permanent Pool (0.327 ac-ft)

EDV = (0.660 ac-ft - 0.327 ac-ft)

= 0.333 ac-ft

3 of 12

July 2015

RETENTION BASIN EXAMPLE

(CONTINUED)

1117-7 REFERENCE SECTION

1117

• The permanent pool elevation is set at 796.0 ft.

o 0.327 ac-ft of storage is permanently ponded.

o 0.327 ac-ft is greater than 0.317 ac-ft; therefore, it is acceptable.

• The EDV volume is between 797.8 ft and 796.0 ft.

o 0.660 ac-ft – 0.327 ac-ft = 0.333 ac-ft

o 0.333 ac-ft is greater than 0.317 ac-ft; therefore, it is acceptable.

Design the Retention Basin Water Quality Outlet:

• The minimum discharge time of the EDV is 24 hours with no more than 50% of the EDV being

released from the retention basin in the first one-third of the 24 hour drain time.

• EDV = 0.317 ac-ft; must take 24 hours or longer to drain

• 50% or less of the EDV (i.e. 0.159 ac-ft) must be drained in 8 hours.

• Choose one 2.5 inch diameter circular orifice at an elevation of 796.0 ft.

• Calculate the drawdown curve.

o This calculation can be done by hand by creating a stage vs. discharge table and

interpolating between values, but it is generally easier to use a model to simulate runoff

through a retention basin such as PondPack or HydroCAD.

• Do not route a design storm hydrograph through a retention basin to determine the drawdown

curve. Start the simulation with the water surface at a level equivalent to the EDV storage (for this

example, at an elevation of 797.80). Then allow the pooled water filling the EDV to drain by gravity

out of the water quality outlet structure. Include all retention basin outlets that would affect this

drawdown curve. Include any downstream constraints such as tailwater or limiting conveyance

downstream. For this example, there is no tailwater and there is a free discharge from the retention

basin.

4 of 12

July 2015

RETENTION BASIN EXAMPLE

(CONTINUED)

1117-7 REFERENCE SECTION

1117

Retention Basin Drawdown Hydrograph:

Time

(hours)

Storage

(acre-feet)

Elevation

(feet)

Discharge

(cfs)

Time

(hours)

Storage

(acre-feet)

Elevation

(feet)

Discharge

(cfs)

0 0.66 797.8 0.22 19 0.405 796.48 0.1

1 0.642 797.72 0.21 20 0.397 796.43 0.1

2 0.625 797.64 0.21 21 0.389 796.39 0.09

3 0.608 797.56 0.2 22 0.382 796.34 0.08

4 0.592 797.48 0.2 23 0.376 796.31 0.07

5 0.576 797.4 0.19 24 0.37 796.27 0.07

6 0.56 797.32 0.18 25 0.365 796.24 0.06

7 0.545 797.25 0.18 26 0.36 796.21 0.05

8 0.531 797.17 0.17 27 0.356 796.18 0.05

9 0.517 797.1 0.17 28 0.352 796.16 0.04

10 0.503 797.03 0.16 29 0.349 796.14 0.03

11 0.49 796.96 0.15 30 0.347 796.13 0.03

12 0.478 796.89 0.15 31 0.345 796.11 0.02

13 0.466 796.83 0.14 32 0.343 796.1 0.02

14 0.454 796.76 0.14 33 0.342 796.09 0.02

15 0.443 796.7 0.13 34 0.34 796.09 0.01

16 0.433 796.64 0.12 35 0.339 796.08 0.01

17 0.423 796.59 0.12 36 0.339 796.07 0.01

18 0.414 796.53 0.11

5 of 12

July 2015

RETENTION BASIN EXAMPLE

(CONTINUED)

1117-7 REFERENCE SECTION

1117

• In 24 hours, the volume goes from 0.660 ac-ft to 0.370 ac-ft.

o 0.660 ac-ft – 0.370 ac-ft = 0.290 ac-ft

• EDV = 0.317ac-ft

o 0.317ac-ft > 0.290 ac-ft. It takes longer than 24 hours to drain the EDV; therefore, it is

acceptable.

• In 8 hours, the volume goes from 0.660 ac-ft to 0.531 ac-ft.

o 0.660 ac-ft – 0.531 ac-ft = 0.129 ac-ft

• 50% EDV = 0.159 ac-ft

o 0.159 ac-ft > 0.129 ac-ft. It takes longer than 8 hours to drain 50% of the EDV; therefore, it

is acceptable.

0.25

0.30

0.35

0.40

0.45

0.50

0.55

0.60

0.65

0.70

0 4 8 12 16 20 24 28 32 36 40 44 48

Vo

lum

e (

ac-

ft)

Time (hours)

Drain Time

Volume vs. Time

(0.660 ac-ft - 0.531 ac-ft)

= 0.129 ac-ft < 50% EDV

(0.660 ac-ft - 0.370 ac-ft)

= 0.290 ac-ft < EDV

Permanent Pool

6 of 12

July 2015

RETENTION BASIN EXAMPLE

(CONTINUED)

1117-7 REFERENCE SECTION

1117

Size the Primary Retention Basin Outlet:

• There are three main parts of a typical retention basin discharge structure:

o Water quality outlet(s)

o Primary outlet

o Overflow weir

• The primary retention basin outlet normally consists of a catch basin grate and the conduit that

conveys discharges from the retention basin during all but the least frequent precipitation events.

• The primary outlet should be sized to convey the 10-year design storm.

ODOT Water Quality Catch Basin Detail (WQ-1.1):

7 of 12

July 2015

RETENTION BASIN EXAMPLE

(CONTINUED)

1117-7 REFERENCE SECTION

1117

Determine the 10-year peak flow rate:

• For the purposes of post-construction BMP calculations, all existing right-of-way is to be

considered impervious. For the purpose of general conveyance sizing, runoff coefficients should

be calculated using Table 1101-2 in ODOT’s L&D Vol. 2.

• Q = CiA

Calculate the weighted C value:

1.5 acres of tributary area are pavement and paved shoulders: C = 0.9

6.0 acres of tributary area are berms and slopes 4:1 or flatter: C = 0.5

Cweighted = �.��∗�. ��.���∗�.

�.�� = 0.58

Determine the precipitation intensity:

Rainfall Area B

tC = 25 min

(The time of concentration is given in this example as 25 minutes because there is

significant overland flow over grassed area. The time of concentration should be

calculated for each site based on the site-specific flow path. 25 minutes would likely be

too high of a value if the detention basin were receiving flow from a piped system. See

the time of concentration calculations below.)

L&D Vol. 2, Figure 1101-2: Area B, 10-year frequency, 25 min tC: i = 3.4 in/hr

• Q = 0.58 * 3.4 in/hr * 7.5 ac = 14.79 cfs

Time of Concentration (tC) Calculations:

o tC = Time of overland flow (tO) + Time of shallow concentrated flow (tS) + Time of channel

flow (tC)

o Overland Flow (tO)

� tO = �,���.��������/�

��/�

� C = Runoff Coefficient (0.58 for this example)

� L = Distance to most remote location in drainage in feet (max. 300 ft.) (200 ft. in this

example)

� s = Overland slope (percent) (0.33% in this example)

� tO = �,���.���.��������/�

�.�/� = 19.16 minutes

o Shallow Concentrated Flow (tS)

� VS = Velocity of shallow concentrated flow (ft/sec) = 3.281ks0.5

� k = Intercept Coefficient (L&D Table 1101-1) = (0.457 in this example)

� s = Overland slope (percent) (0.33% in this example)

� VS = 3.281 * 0.457 * 0.330.5 = 0.86 ft/sec

� Length of shallow concentrated flow = 200 ft.

� tS = 200 ft. / 0.86 ft/sec = 233 sec = 3.88 minutes

8 of 12

July 2015

RETENTION BASIN EXAMPLE

(CONTINUED)

1117-7 REFERENCE SECTION

1117

o Channel Flow (tC)

� Manning’s Equation: V = �.� ��/���/�

�

� V = velocity in the channel (ft/sec)

� r = hydraulic radius (0.69 ft. in this example)

� s = channel slope (0.01 ft/ft in this example)

� n = Manning’s Roughness Coefficient (L&D Vol. 2, Table 1102-3) (0.03 in this

example)

� V = �.� ∗�.� �/�∗�.���/�

�.� = 3.88 ft/sec

� Channel length = 500 ft. (for this example)

� tC = 500 ft. / 3.88 ft/sec = 129 sec. = 2.15 minutes

o tC = tO + tS + tC = 19.16 + 3.88 + 2.15 = 25.19 minutes. Use tC = 25 minutes

Size the primary retention basin discharge conduit:

• The discharge conduit must be large enough to convey the 10-year design storm, keeping the

maximum hydraulic grade line within the crown of the pipe.

• This example has the following conduit characteristics:

o Conduit slope = 0.005 ft/ft

o No Tailwater; free discharge

o Pipe Roughness Coefficient = 0.015 (L&D Vol. 2, Section 1104.4.5)

• The minimum conduit size that conveys the 10-year peak flow (14.79 cfs) with the given

characteristics is a 24-inch diameter pipe.

Set the catch basin grate elevation:

• The EDV fills the retention basin to an elevation of 797.8 ft. At water surface elevations of 797.8

ft and below, all discharge should pass through the water quality outlet. (In this example, the

water quality outlet is one 2.5 inch diameter orifice at 796.0 ft.)

• The ODOT standard water quality catch basin detail (SCD WQ-1.1) calls for either Catch Basin

No. 2-3 or 2-4 depending on the outlet pipe size. Both catch basins have a 6-inch high side inlet

that is either 3 or 4 feet wide depending on the catch basin. See the detail:

9 of 12

July 2015

RETENTION BASIN EXAMPLE

(CONTINUED)

1117-7 REFERENCE SECTION

1117

ODOT Catch Basin No. 2-3 and No. 2-4:

• However, SCD WQ-1.1 calls for a catch basin used for a detention basin to not have the side inlet

windows. Therefore, side inlets should not be included in a detention basin outlet structure.

• The elevation of the top of the grate should be set at the EDV elevation. Therefore, any volume

above the EDV may discharge into the catch basin through the grate.

o Catch basin grate elevation = 797.8 ft

Set the Overflow Weir Invert Elevation:

• The 10-year peak flow rate (14.79 cfs) should pass fully through the primary discharge.

Therefore, no flow should discharge from the overflow weir until the 10-year flow rate has been

exceeded.

• Set the overflow weir invert elevation just high enough above the catch basin grate such that

the full 10-year peak flow rate is conveyed through the primary discharge.

July 2015

10 of 12

RETENTION BASIN EXAMPLE

(CONTINUED)

1117-7 REFERENCE SECTION

1117

• For this example, the primary discharge pipe is sized at 24 inches in diameter; therefore, Catch

Basin No. 2-3 is appropriate.

• Catch Basin No. 2-3 has the same grate as Catch Basin No. 2-2B.

• The water quality catch basin has one openings to allow runoff inside; Grate No. 2-2-B.

• Use L&D Vol. 2, Figure 1102-1 to determine the necessary head above a No. 2-2-B grate to pass

the 10-year peak flow rate (14.79 cfs).

• According to Figure 1102-1, 1.25 ft of head is required to pass a flow rate of 14.79 cfs.

• Add the necessary head to the grate elevation (797.8 ft)

o 797.8 ft + 1.25 ft = 799.05 ft

• Set the overflow weir elevation at 799.05 ft.

Size the Emergency Overflow Weir and Set the Top of Basin Elevation:

• L&D Vol. 2, Section 1104.4.2 states that the hydraulic grade line should be checked for the 25-

year storm.

• Calculate the peak flow rate for each design storm:

o 25-year intensity @ tC = 25 min and Rainfall Area B: 3.8 in/hr

o 25-year storm peak flow rate: Q = CiA = 0.58 * 3.8 in/hr * 7.5 ac = 16.53 cfs

• Calculate the required weir length for each design storm flow:

o Emergency overflow weir elevation = 799.05 ft

o Assume a top of retention basin elevation = 799.55 ft

o Maximum height overflow weir = 799.55 ft – 798.05 ft = 0.5 ft

o Weir equation: Q = C*L*H1.5

� C = 3

� H = 0.5

� L = ?

o Length of a weir: L = �

�∗��.

o 25-year: L = ��.

∗�.�. = 15.6 ft

• Provide a 16 ft wide overflow weir.

• The top of basin elevation is 799.55 ft.

• The overflow weir length could be reduced by increasing the top of basin elevation. Or the top

of basin elevation can be lowered by increasing the overflow weir length. The 25-year peak flow

rate must fully pass through the overflow weir without overtopping the detention basin.

• Flow rates greater than the 25-year peak flow rate may overtop the detention basin

uncontrolled.

• Provide erosion protection at the overflow weir, to the bottom of the berm, and continuing

downstream if there is erosion potential.

11 of 12

July 2015

RETENTION BASIN EXAMPLE

(CONTINUED)

1117-7 REFERENCE SECTION

1117

Design Anti-Seep Collars:

• Anti-seep collars reduce the conveyance of flow along pipe bedding, outside of a conduit and

increase the flow path for the seepage of water. This helps protect the berm above the

discharge conduit from a retention basin from internal erosion.

ODOT Standard Drawing WQ-1.2

• Calculate the saturated zone length along the conduit (Ls)

o Ls = Y(Z+4)[1+S/(0.25-S)]

o Y = depth of water during the 10-year storm

o Z = slope of embankment

o S = slope of conduit

• Maximum elevation at 10-year storm = 799.05 ft

• Conduit elevation = 795.0 ft

• Y = 799.05 ft – 795.0 ft = 4.05

• Z = 4

• S = 0.005

• Ls = 4.05(4+4)[1+0.005/(0.25-0.005)] = 33.06 ft

• ΔLs = 0.15*Ls = 0.15 * 33.06 ft = 5.0 ft

• Total Projection: P = W – D

o W = 2ft + 2 ft diameter + 2 ft = 6 ft

o P = 6 ft – 2 ft = 4 ft

• Number of collars = ΔLs / P = 5.0 ft / 4 ft = 1.25

o Minimum of 2 collars per outlet conduit

o Use 2 anti-seep collars

• Place both anti-seep collars in the saturation zone (within 33.06 ft of front edge of berm).

• Spacing between collars: between 10 and 25 feet

12 of 12

July 2015

RETENTION BASIN EXAMPLE

(CONTINUED)

1117-7 REFERENCE SECTION

1117

Additional Considerations:

• Vegetate the sides of the retention basin that are above the permanent pool with Item 670

Slope Erosion Protection per L&D Vol. 2, Section 1117.3.1.

• For all open water carriers at each inlet and discharge from a retention basin, check the shear

stress and ensure appropriate lining per L&D Vol. 2, Section 1102.3.2.

• For all culverts that discharge into or out of a retention basin, ensure that appropriate rock

channel protection is included per L&D Vol. 2, Section 1107.2.

• Include calculated retention basin ponding elevations in the calculation of the hydraulic grade

line for the upstream conveyance system per L&D Vol. 2, Section 1104.4.2.

• Attempt to locate structures outside of designated flood plains. If a retention basin encroaches

on a flood plain, follow the flood assessment requirements in L&D Vol. 2 Section 1005.

• Ensure that safety criteria are met in the clear zone per L&D Vol. 1, Section 600.2.

• Ensure that no more than one foot of permanent standing water is located within the clear zone

without barrier protection, per L&D Vol. 1, Section 601.1.1.

• Engage local project stakeholders in potential public safety considerations associated with

retention basins.

• Develop a plan for how regular maintenance will be performed.

o Vehicle access

o Mowing

o Removal of woody vegetation

o Regular unclogging of the water quality outlet

January 2016

AA

Provid

e Pretreat

ment per L

&D

Vol. 2, Sec. 1117.5.1

Bioretentio

n Cell

Area

Catch Basin

Perforated P

VC

Underdrain,

Maxim

um 20'

Spacin

g

Observatio

n

Well / Cleanout

1117-8

1117.5

REFERENCE SECTION

NO

T T

O S

CA

LE

PL

AN

VIE

W BIO

RE

TE

NTIO

N C

EL

L IN

OP

EN

AR

EA

WIT

H L

EV

EL S

UR

FA

CE

BIORETENTION CELL

January 2016

30" 12"3"3"

3"

Fin

e

Aggregate per C

MS 703.20

Coarse

Aggregate, Siz

e no. 78 per C

MS 703.20

Coarse

Aggregate, Siz

e no. 57 per C

MS 703.20

Maxim

um 12

" Pondin

g

Allo

wed

(See Standard

Note

W10

1 for Soil

Mix)

Bioretentio

n Plantin

g Soil

12"

Catch Basin

Observatio

n

Well / Cleanout

(See Plans for Siz

e and Length)

Ite

m 611 Conduit,

Peforated P

VC

Underdrain

Subsoil

Excess 3" for Settlin

g

Fin

al

Grade

Perforated

Underdrain

Minim

um 3"

of no. 57

Aggregate under

BIORETENTION CELL (CONT.)1117-8

1117.5

REFERENCE SECTION

NO

T T

O S

CA

LE

SE

CTIO

N

A-

A (BIO

RE

TE

NTIO

N C

EL

L)

January 2016

of dit

ch

Centerlin

e

10"

Earth

Dik

e

6:1 Slope or Flatter

Rounded

Flo

wlin

e of

Dit

ch

See

Detail this page

Observatio

n

Well / Cleanout

L&

D

Vol. 2, Sec. 1117.5.2

Provid

e Pretreat

ment Per

Maxim

um 12

" Pondin

g

Allo

wed

Rounded

Bioretentio

n Cell

Area

Approx. 2"

Thic

k

Perforated P

VC

Underdrain

Perforated P

VC

Underdrain

on the Plans

Outlet as Sho

wn

and

Non-perforated Conduit

Coupler bet

ween Perforated

Subsoil

Ite

m 611 Type C Conduit

Non-perforated P

VC

Underdrain

Ite

m 611, Tie

d Concrete Block

Mat, Type 1

Type 1

Coverin

g Earth

Dik

e

Ite

m 601, Tie

d Concrete Block

Mat,

Earth

Dik

e

BIORETENTION CELL (CONT.)1117-8

1117.5

REFERENCE SECTION

NO

T T

O S

CA

LE

PR

OFIL

E

OF BIO

RE

TE

NTIO

N C

EL

L IN

GR

ASS

DIT

CH

NO

T T

O S

CA

LE

PL

AN

VIE

W LIN

EA

R BIO

RE

TE

NTIO

N C

EL

L IN

GR

ASS

DIT

CH

January 2016

Fine Aggregate per CMS 703.20

30"

3"

12"

3"

3"

4"

See Plans for Bioretention Cell Width

NOT TO SCALE

SECTION OF BIORETENTION CELL IN GRASS DITCH

Ditch Centerline

under Perforated Underdrain

Minimum 3" of no. 57 Aggregate

Subsoil

Subsoil

Final Grade

Excess 3" for Settling

CMS 611, Threaded Cap

4" Type F Conduit, PVC per

Observation Well / Cleanout

Perforated PVC Underdrain

per CMS 703.20

Coarse Aggreage, Size no. 78

per CMS 703.20

Coarse Aggregate, Size no. 57

for Soil Mix)

(See Standard Note W101

Bioretention Planting Soil

BIORETENTION CELL (CONT.)1117-8

1117.5

REFERENCE SECTION

NOT TO SCALE

OBSERVATION WELL / CLEANOUT

PAYMENT:

BASIN MATERIALS:

NOTES

EROSION CONTROL:

BIORETENTION PLANTING SOIL:

Cells) for approved bioretention planting soil characteristics.

See Plan Note W101 (Bioretention

PLANTINGS:

CMS 671 over the surface of all bioretention planting soil.

temporary erosion control mat Type A, B, C, or E per

For grassed bioretention, include

SUBSOIL:

bioretention cell area.

cell area per CMS 659. Do not apply fertilizer or lime to the

If not specified on the plans, seed the bioretention

BIORETENTION SIDES

of aggregate into bioretention cell.

Scarify the subsoil 3" minimum before installation

grate as specified. Do not use side inlet windows.

Provide basin dimensions, materials, and

vertical sides unless otherwise specified.

Construct bioretention cells with

item 671, Erosion Control Mats sq yd.

and Mulching sq yd. Erosion control mats will be paid for as

the bioretention cell will be paid for as Item 659, Seeding

paid for as Item 611, Outlet Pipe. Seeding and mulching for

Underdrain as per plan. Non perforated underdrains will be

associated fittings and couplers will be paid for as Item 605,

plan cu yd. Perforated underdrains, observation wells, and

Excavation will be paid for as Item 203, Excavation as per

Bioretention Cell cu yd and Item 601 Tied Concrete Mat sq yd.

Bioretention cell will be paid for as Iem 601,

BIORETENTION CELL (CONT.)1117-8

1117.5

REFERENCE SECTION

January 2016

Appendix A – Reproducible Forms

April 2017

Form Subject

LD-33 County Engineer Approval Form

LD-34 Storm Sewer Computation Sheet

LD-35 Ohio Drainage Design Criteria Form

LD-40 Gutter Spread and Inlet Capacity Computation Sheet

LD-41 Ditch Computation Sheet

LD-42 Culvert Computation Sheet

LD-50 No-Rise Certification

LD-51 Floodplain Letter of Compliance Template

LD-52 Floodplain Letter of Notification Template

Appendix A – Reproducible Forms

April 2017

Form LD-33

Revised July 2011

Date Submitted to District:

Date Submitted to County Engineer:

County - Route - Section:

PID:

Inlet Outlet Inlet Outlet

Comments:

Ohio Department of TransportationCounty Engineer

DateCounty Engineer's Signature

County

SkewCulvert Invert Elevation Existing Channel Elevation

Size & Type

I have reviewed and hereby approve the drainage proposed for the highway designated hereon in accordance with the provisions of the Ohio Revised Code, Section 6131.631.

Approval Form

Station

LD-33.xls

Form LD-35 Revised January 2015 PROJECT INFORMATION:

COUNTY ROUTE SECTION PID

PIPE POLICY: The Pipe Policy of _____________________ will be used for this project. ____________________________________________________________________________________________ ____________________________________________________________________________________________ ____________________________________________________________________________________________ (Attach a copy of the written pipe policy or furnish a link to the policy. In lieu of a written policy, documentation of locally funded construction practices may be provided) POST CONSTRUCTION BMP POLICY: The Post Construction BMP Policy of _____________________ will be used for this project. If a policy other than ODOT’s is being used, the following BMP’s are permitted: ____________________________________________________________________________________________ ____________________________________________________________________________________________ ____________________________________________________________________________________________ DRAINAGE WATERSHED(S): ____________________________________________________________________________________________ ____________________________________________________________________________________________ ____________________________________________________________________________________________ PROJECT SPECIFIC INFORMATION AFFECTING DRAINAGE: ____________________________________________________________________________________________ ____________________________________________________________________________________________ ____________________________________________________________________________________________

No-Rise Certification Form LD-50 Revised January 2015

This is to certify that I am a qualified licensed professional engineer in the State of Ohio. It is to

further certify that the attached analysis supports the fact that the proposed Roadway project:

_____________________________________________ in the floodway will not increase the (Name of Project)

Base Flood Elevation (100-year flood), floodway elevation, or floodway widths on

______________________________________ at published sections in the Flood Insurance (Name of Stream)

Study for ______________________________________, dated ____________________ (Name of Community)

and will not increase the Base Flood Elevations (100-year flood), floodway elevations, or

floodway widths at unpublished cross-sections in the vicinity of the proposed roadway project.

Engineer’s Name:___________________________________________

Signature:________________________________________ Date:_______________________

Phone Number:___________________ E-MAIL:__________________________________

Agency/Firm: _____________________________________________________________

Address:_____________________________________________________________________

City:____________________________ State:____________ Zip Code:_______________

ENGINEERS SEAL:

Company Letter Head or ODOT Letter Head

Date

Name of Floodplain Coordinator

Title

County or Municipality Name

Address Line 1

Address Line 2

Re: County-Route-Section (PID)

Letter of Compliance

Dear Name of Floodplain Coordinator:

Enclosed please find the floodplain analysis for Ohio Department of Transportation project

County-Route-Section (PID). The subject roadway project encroaches upon a Special Flood

Hazard Area Zone A or AE within your community at the location identified in the attached

report. The hydraulic calculations and No-Rise Certification Form (if Zone AE) provide the

necessary documentation of compliance to all federal, state, and local floodplain standards as

required.

If you need additional information please contact contact information as needed.

Respectfully,

Name of Registered Engineer, P.E.

Title

Form LD-51

Revised January 2017

Company Letter Head or ODOT Letter Head

Date

Name of Floodplain Coordinator

Title

County or Municipality Name

Address Line 1

Address Line 2

Re: County-Route-Section (PID)

Letter of Notification

Dear Name of Floodplain Coordinator:

The Ohio Department of Transportation project County-Route-Section (PID) encroaches upon

a Special Flood Hazard Area Zone A or AE within your community.

The proposed project list the intent and work.

Please provide your community’s flood zone regulations if they differ from FEMA

requirements and forward any questions you may have about the project. Future

correspondence will include hydraulic calculations and required documentation for compliance.

We will move forward with this project if no concerns are brought to our attention.

If you need additional information please contact contact information as needed.

Respectfully,

Name of Registered Engineer, P.E.

Title

Form LD-52

Revised January 2017

Appendix B – Sample Plan Notes

April 2017

The Sample plan notes included in this Appendix are the most frequently used. Each note is accompanied by a “Designer Note” in an attempt to give some guidance as to when the note should be used and how to estimate quantities for some of the items where the methods for quantity calculations are not obvious.

The following note categories are included:

Category Letter Prefix

Drainage Notes DErosion Control Notes EWater Quality Notes W

Appendix B – Sample Plan Notes

April 2017

Appendix B – Sample Plan Notes

April 2017

DRAINAGE (D), EROSION CONTROL (E), & WATER QUALITY (W)

No. NAME

D101 Item 611 - Catch Basin GrateD102 Note Deleted (January 2002)D103 Item Special - Fill and Plug Existing ConduitD104 Crossings and Connections to Existing Pipes and UtilitiesD105 Pipe Connections to Corrugated Metal StructuresD106 Item 611 - Tunnel Liner Plate StructureD107 Farm DrainsD108 Item 605 - Aggregate DrainsD109 Spring DrainsD110 Unrecorded Untreated Stormwater DrainageD111 Unrecorded Treated Stormwater DrainageD112 Item 611 - Conduit Bored or JackedD113 Item 611 - Conduit Under RailroadD114 Review of Drainage FacilitiesD115 Unrecorded Stormwater DrainageD116 Unrecorded Active Sanitary Sewer ConnectionsD117 Manholes, Catch Basins and Inlets Removed or AbandonedD118 Item 511 Wingwalls or Headwalls for 611 ItemsD119 Item Special - Miscellaneous MetalD120 Item 611 - Slotted DrainD121 Item Special - Pipe CleanoutD122 Item 611 - Conduit Misc.: Cured-In-Place Pipe Liner D123 Existing UnderdrainsD124 Temporary Drainage Items

E101 Seeding and MulchingE102 Sodding

W99 Post Construction Storm Water TreatmentW100 DeletedW101 Bioretention Cell(s)W102 Infiltration Trench (or Basin)W103 Manufactured Water Quality Structure

Appendix B – Sample Plan Notes

April 2017

D101 ITEM 611 - CATCH BASIN GRATE

EXISTING CATCH BASINS SHALL BE MODIFIED BY REPLACING THE EXISTING GRATES WITH BICYCLE SAFE GRATES. QUANTITIES AND LOCATIONS ARE SHOWN IN THE PLANS AND SHALL BE PAID FOR AT THE CONTRACT PRICE FOR ITEM 611, EACH, CATCH BASIN GRATE, TYPE .

Designer Note: The above note should be used on projects where existing catch basin grates are not bicycle safe. The size and type of grate to be supplied must be indicated. There may be more than one type and size on a project.

If specific locations are not shown in the plan, or additional grates are to be included on a contingency basis, the following should either replace the second sentence in the note or be added to the note:

THE FOLLOWING ESTIMATED QUANTITIES HAVE BEEN INCLUDED IN THE GENERAL SUMMARY FOR USE AS DIRECTED BY THE ENGINEER FOR REPLACEMENT OF EXISTING CATCH BASIN GRATES WITH BICYCLE SAFE GRATES:

611, CATCH BASIN GRATE, TYPE , EACH

D103 ITEM SPECIAL - FILL AND PLUG EXISTING CONDUIT

THIS ITEM SHALL CONSIST OF THE CONSTRUCTION OF BULKHEADS IN AN EXISTING ____ IN DIAMETER CONDUIT AND FILLING THE AREA THUS SEALED OFF WITH ITEM 613, SAND OR OTHER MATERIAL APPROVED BY THE ENGINEER.

BULKHEADS SHALL BE LOCATED AT THE LIMITS OF THE AREA TO BE FILLED AS INDICATED ON THE PLANS. THE BULKHEADS SHALL CONSIST OF BRICK OR CONCRETE MASONRY WITH A MINIMUM THICKNESS OF 12 INCHES.

THE FILL MATERIAL SHALL BE PUMPED INTO PLACE, OR PLACED BY OTHER MEANS APPROVED BY THE ENGINEER, SO THAT, AFTER SETTLEMENT, AT LEAST 90 PERCENT OF THE CROSS-SECTIONAL AREA OF THE CONDUIT, FOR ITS ENTIRE LENGTH, SHALL BE FILLED. THE LENGTH OF FILLED AND PLUGGED CONDUIT TO BE PAID FOR SHALL BE THE ACTUAL NUMBER OF FEET (MEASURED ALONG THE CENTERLINE OF EACH CONDUIT FROM OUTER FACE TO OUTER FACE OF BULKHEADS) FILLED AND PLUGGED AS DESCRIBED ABOVE.

IN LIEU OF FILLING AND PLUGGING THE EXISTING CONDUIT, THE PIPE MAY BE CRUSHED AND BACKFILLED IN ACCORDANCE WITH THE PROVISIONS OF 203, OR IT MAY BE REMOVED. THE LENGTH, MEASURED AS PROVIDED ABOVE, SHALL BE PAID FOR AT THE CONTRACT PRICE PER FOOT FOR, ITEM SPECIAL, FILL AND PLUG EXISTING CONDUIT.

Designer Note: The above note should be used when it is desired to abandon an existing conduit by filling and plugging rather than more conventional methods. If the conduit is in shallow fill, the designer may delete the crush and backfill option specified in the fourth paragraph. Add pay item 202E70000 “202, Special – Fill and plug existing conduit, ___ft” to the plans.

Appendix B – Sample Plan Notes

April 2017

D104 CROSSINGS AND CONNECTIONS TO EXISTING PIPES AND UTILITIES

WHERE PLANS PROVIDE FOR A PROPOSED CONDUIT TO BE CONNECTED TO, OR CROSS OVER OR UNDER AN EXISTING SEWER OR UNDERGROUND UTILITY, THE CONTRACTOR SHALL LOCATE THE EXISTING PIPES OR UTILITIES BOTH AS TO LINE AND GRADE BEFORE STARTING TO LAY THE PROPOSED CONDUIT.

IF IT IS DETERMINED THAT THE ELEVATION OF THE EXISTING CONDUIT, OR EXISTING APPURTENANCE TO BE CONNECTED, DIFFERS FROM THE PLAN ELEVATION OR RESULTS IN A CHANGE IN THE PLAN CONDUIT SLOPE, THE ENGINEER SHALL BE NOTIFIED BEFORE STARTING CONSTRUCTION OF ANY PORTION OF THE PROPOSED CONDUIT WHICH WILL BE AFFECTED BY THE VARIANCE IN THE EXISTING ELEVATIONS.

IF IT IS DETERMINED THAT THE PROPOSED CONDUIT WILL INTERSECT AN EXISTING SEWER OR UNDERGROUND UTILITY IF CONSTRUCTED AS SHOWN ON THE PLAN, THE ENGINEER SHALL BE NOTIFIED BEFORE STARTING CONSTRUCTION OF ANY PORTION OF THE PROPOSED CONDUIT WHICH WOULD BE AFFECTED BY THE INTERFERENCE WITH AN EXISTING FACILITY.

PAYMENT FOR ALL THE OPERATIONS DESCRIBED ABOVE SHALL BE INCLUDED IN THE CONTRACT PRICE FOR THE PERTINENT 611 CONDUIT ITEM.

Designer Note: The above note is to be used when the designer is unsure of the exact location of a conduit that will require an extension or where the potential for interference between proposed and existing conduits exists.

D105 PIPE CONNECTIONS TO CORRUGATED METAL STRUCTURES

CONNECTIONS OF PROPOSED LONGITUDINAL DRAINAGE TO CORRUGATED METAL STRUCTURES SHALL BE MADE BY MEANS OF A SHOP FABRICATED OR FIELD WELDED STUB ON THE STRUCTURE. THE STUB SHALL MEET THE REQUIREMENTS OF 707 AND HAVE A MINIMUM LENGTH OF 2 FEET AND A MINIMUM WALL THICKNESS OF 0.064 INCHES.

THE LOCATION AND ELEVATION OF THE STUB ARE TO BE CONSIDERED APPROXIMATE AND MAY BE ADJUSTED BY THE ENGINEER TO AVOID CUTTING THROUGH JOINTS IN THE STRUCTURE.

THE FIELD WELDED JOINT, IF USED, SHALL BE THOROUGHLY CLEANED AND REGALVANIZED OR OTHERWISE SUITABLY REPAIRED. WELDING SHALL MEET THE REQUIREMENTS OF 513.21.

A MASONRY COLLAR, AS PER STANDARD DRAWING DM-1.1, WILL BE REQUIRED TO CONNECT THE LONGITUDINAL DRAINAGE TO THE STUB, WHEN PIPE OTHER THAN CORRUGATED METAL IS PROVIDED FOR THE LONGITUDINAL DRAINAGE.

PAYMENT FOR CUTTING INTO THE STRUCTURE AND PROVIDING THE CONNECTION DESCRIBED, SHALL BE INCLUDEDIN THE CONTRACT PRICE FOR ITEM 611 OR 522.

Designer Note: Use the above note on all projects where connections are proposed to existing corrugated metal conduits.

Appendix B – Sample Plan Notes

April 2017

D106 ITEM 611 - TUNNEL LINER PLATE STRUCTURE

IN LIEU OF THE PROVISIONS OF 611.02, MATERIAL FURNISHED FOR THE LINER PLATE STRUCTURE SHALL BE AS MANUFACTURED BY: AMERICAN COMMERCIAL, INC.; COMMERCIAL INTERTECH, CORP.; CONTECH CONSTRUCTION PRODUCTS, INC.; OR AN APPROVED EQUAL. BASE METAL COMPOSITION, DEPTH AND SPAN OF THE CORRUGATIONS, AND SIZE AND SPACING OF BOLTS AND BOLT HOLES SHALL BE IN ACCORDANCE WITH THE DETAILS OF THE MANUFACTURER. INSTALLATION OF THE STRUCTURE SHALL BE IN ACCORDANCE WITH THE MANUFACTURER’S RECOMMENDATIONS. THE PLATE THICKNESS AND SECTION MODULUS OF THE MATERIAL FURNISHED SHALL NOT BE LESS THAN THAT INDICATED ON THE STRUCTURE DETAILS.

GALVANIZING, IF SPECIFIED, SHALL BE IN ACCORDANCE WITH 707.03 AND SHALL BE DONE AFTER CORRUGATING, FORMING, AND PUNCHING THE PLATES AND BOLT HOLES. GRANULAR BEDDING WILL NOT BE REQUIRED. THE COMPLETED STRUCTURE SHALL CONFORM TO THE REQUIREMENTS OF 707. BITUMINOUS COATING, IF SPECIFIED, SHALL MEET THE REQUIREMENTS OF 707.05.

Designer Note: If the space between the tunnel excavation and the tunnel liner plate is to be filled with grout, the composition of the grout and spacing of the grout couplings should be shown.

D107 FARM DRAINS

ALL FARM DRAINS, WHICH ARE ENCOUNTERED DURING CONSTRUCTION, SHALL BE PROVIDED WITH UNOBSTRUCTED OUTLETS. EXISTING COLLECTORS WHICH ARE LOCATED BELOW THE ROADWAY DITCH ELEVATIONS, AND WHICH CROSS THE ROADWAY, SHALL BE REPLACED WITHIN THE (RIGHT OF WAY)( CONSTRUCTION) LIMITS BY ITEM 611 CONDUIT, TYPE B, ONE COMMERCIAL SIZE LARGER THAN THE EXISTING CONDUIT.

EXISTING COLLECTORS AND ISOLATED FARM DRAINS, WHICH ARE ENCOUNTERED ABOVE THE ELEVATION OF ROADWAY DITCHES, SHALL BE OUTLETTED INTO THE ROADWAY DITCH BY 611 TYPE F CONDUIT. THE OPTIMUM OUTLET ELEVATION SHALL BE ONE FOOT ABOVE THE FLOWLINE ELEVATION OF THE DITCH. LATERAL FIELD TILES WHICH CROSS THE ROADWAY SHALL BE INTERCEPTED BY 611, TYPE E CONDUIT, AND CARRIED IN A LONGITUDINAL DIRECTION TO AN ADEQUATE OUTLET OR ROADWAY CROSSING.

THE LOCATION, TYPE, SIZE AND GRADE OF REPLACEMENTS SHALL BE DETERMINED BY THE ENGINEER AND PAYMENT SHALL BE MADE ON FINAL MEASUREMENTS.

EROSION CONTROL PADS AND ANIMAL GUARDS SHALL BE PROVIDED AT THE OUTLET END OF ALL FARM DRAINS AS PER STANDARD CONSTRUCTION DRAWING DM-1.1, EXCEPT WHEN

THEY OUTLET INTO A DRAINAGE STRUCTURE. PAYMENT FOR THE EROSION CONTROL PADS AND ANIMAL GUARDS AND ANY NECESSARY BENDS OR BRANCHES SHALL BE INCLUDED FOR PAYMENT IN THE PERTINENT CONDUIT ITEMS.

THE FOLLOWING ESTIMATED QUANTITIES HAVE BEEN INCLUDED IN THE GENERAL SUMMARY FOR THE WORK NOTED ABOVE:

611 “ CONDUIT, TYPE B ________ FT611 “ CONDUIT, TYPE E ________ FT611 “ CONDUIT, TYPE F ________ FT 601 ROCK CHANNEL PROTECTION TYPE C WITH FILTER ________ CU. YDDesigner Note: The above note is to be used where excavation may conflict with existing farm drains. Use of a lateral field interceptor tile located on a temporary easement outside the limited

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access right of way may be appropriate on limited access facilities.

D108 ITEM 605 - AGGREGATE DRAINS

AGGREGATE DRAINS SHALL BE PLACED AT 50 FOOT INTERVALS ON EACH SIDE OF NORMAL CROWNED SECTIONS, STAGGERED SO THAT EACH DRAIN IS 25 FEET FROM THE ADJACENT DRAIN ON THE OPPOSITE SIDE, AND AT 25 FOOT INTERVALS ON THE LOW SIDE ONLY OF SUPERELEVATED SECTIONS. AN AGGREGATE DRAIN SHALL BE PLACED AT THE LOW POINT OF EACH SAG VERTICAL CURVE.

Designer Note: This note should be used on long projects with aggregate drains. On short projects, such as bridge replacements, the station and side for aggregate drain placement should be specified in the plans.

D109 SPRING DRAINS

THE FOLLOWING ESTIMATED QUANTITIES HAVE BEEN CARRIED TO THE GENERAL SUMMARY FOR USE AS DIRECTED BY THE ENGINEER FOR DRAINING ANY SPRINGS SHOWN IN THE PLAN OR ENCOUNTERED DURING CONSTRUCTION. THE FOLLOWING TYPES OF PIPES MAY BE USED: 707.33, 707.41, 707.42 or 707.45 PERFORATED PER 707.31.

SPRING DRAINS SHALL BE CONSTRUCTED AS SHOWN ON STANDARD CONSTRUCTIONDRAWING DM-1.1 AND PAID FOR AT THE CONTRACT PRICE FOR:

605, 6" UNCLASSIFIED PIPE UNDERDRAINS FOR SPRINGS ________ FT. 605, AGGREGATE DRAINS FOR SPRINGS ________ FT. 611, PRECAST REINFORCED CONCRETE OUTLET ________ EACH

Designer Note: This note should be used only where springs are present in the project area and/or the project area is known to have spring activity. In addition to quantities required to drain springs located by field work, estimated contingency quantities should be included for draining springs encountered during construction.

D110 UNRECORDED UNTREATED NON-STORMWATER DRAINAGE

FURNISH NO CONTINUANCE FOR ANY UNRECORDED UNTREATED NON-STORMWATER DRAINAGE SUCH AS UNTREATED SEPTIC, UNTREATED WASTEWATER, UNTREATED CURTAIN/GRADIENT DRAINS, AND UNTREATED FOUNDATION FLOOR DRAINS DISTURBED BY THE WORK. PLUG ANY UNRECORDED UNTREATED NON-STORMWATER DRAINAGE WITH CONCRETE AT THE RIGHT OF WAY LINE. PAYMENT FOR PLUGGING SHALL BE INCLUDED IN THE CONTRACT PRICE FOR THE PERTINENT 202 OR 203 ITEM.

Designer Note: This note is to be used only if there is a possibility that during construction there may be a need for additional plugging of untreated non-stormwater drainage. The Designer shall make a complete investigation for the presence of untreated non-stormwater drainage. List quantities required for all untreated non-stormwater drainage at the specific locations on the Plan & Profile sheets. All located untreated non-stormwater drainage is required to be plugged with concrete at the right-of-way line.

D111 UNRECORDED TREATED NON-STORMWATER DRAINAGE

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FURNISH A CONTINUANCE FOR ALL UNRECORDED TREATED NON-STORMWATER DRAINAGE, SUCH AS TREATED SEPTIC, TREATED WASTEWATER, TREATED CURTAIN/GRADIENT DRAINS, AND TREATED FOUNDATION FLOOR DRAINS DISTURBED BY THE WORK. FURNISH EITHER AN OPEN CONTINUANCE OR AN UNOBSTRUCTED CONTINUANCE BY CONNECTING A CONDUIT THROUGH THE CURB OR INTO A DRAINAGE STRUCTURE. THE LOCATION, TYPE, SIZE AND GRADE OF THE NEEDED CONDUIT TO REPLACE OR EXTEND AN EXISTING DRAIN WILL BE DETERMINED BY THE ENGINEER. ALL SUCH CONTINUANCE REQUIRES A RIGHT OF WAY USE PERMIT. A CONTINUANCE MAY ALSO REQUIRE A NPDES PERMIT FROM THE OHIO ENVIRONMENTAL PROTECTION AGENCY. REPORT ALL CONTINUANCE TO THE LOCAL HEALTH DEPARTMENT.

WHERE MAKING A CONNECTION INTO A HIGHWAY DRAINAGE CONDUIT, AN INSPECTION WELL SHALL BE PROVIDED IN ACCORDANCE WITH STANDARD CONSTRUCTION DRAWING DM-3.1.

THE FOLLOWING ESTIMATED QUANTITIES HAVE BEEN INCLUDED IN THE GENERAL SUMMARY FOR USE AS DIRECTED BY THE ENGINEER IN MAKING THE ABOVE CONTINUANCE:

611, ______ “ CONDUIT, TYPE C ________ FT.

611, INSPECTION WELL ________ EACH

Designer Note: This note is to be used only if there is a possibility that during construction there may be a need for additional continuance of treated non-stormwater drainage. The Designer shall make a complete investigation for the presence of treated non-stormwater drainage. List quantities required for all treated non-stormwater drainage at the specific locations on the Plan & Profile sheets. All located treated non-stormwater drainage is required to have a right of way use permit. If any such located treated non-stormwater drainage do not have a right of way use permit then notice of such is required to be sent to the appropriate parities. All treated non-stormwater drainage may also require a NPDES permit from the Ohio Environmental Protection Agency. Report all continuance to the local health department.

D112 ITEM 611 - CONDUIT BORED OR JACKED

WHERE IT IS SPECIFIED THAT A CONDUIT BE INSTALLED BY THE METHOD OF BORING OR JACKING, NO TRENCH EXCAVATION SHALL BE CLOSER THAN _____ FEET TO THE (EDGE OF PAVEMENT) (NEAREST RAIL). PROVIDE A STEEL CASING PIPE CONFORMING TO 748.06 HAVING JOINTS WITH A CIRCUMFERENCIAL FULLY PENETRATING B-U4B WELD THAT IS PERFORMED BY AN ODOT APPROVED FIELD WELDER. THE INSTALLED CASING PIPE IS THE STORM WATER CONVEYANCE CARRIER UNLESS OTHERWISE SPECIFIED IN THE PLANS. HYDROSTATIC TESTING IS NOT REQUIRED FOR THE CASING PIPE.

Designer Note: The pay item in the General Summary shall read, 611 Conduit Bored or Jacked, “, Type , Ft. Where a conduit is installed by this method under a railroad, the designer should coordinate with the Rail Company to determine the allowable distance from the nearest rail and add note D113 to the plans. Specify a concrete masonry collar between the casing pipe and adjacent conduit material if the casing pipe is used as the final carrier pipe.

D113 ITEM 611 – CONDUIT UNDER RAILROAD

THE STATE SHALL PAY TO THE RAIL COMPANY ALL COSTS FOR WATCHMEN OR

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FLAGGERS DEEMED NECESSARY BY THE RAIL COMPANY, OR OCCASIONED BY THE OPERATIONS OF THE CONTRACTOR, OR ANY SUB-CONTRACTOR, IN CARRYING FORWARD THE INSTALLATION OF PIPE OR CONDUIT UNDER THE RAILROAD PER THE PLAN. THE COSTS FOR WATCHMEN OR FLAGGERS REQUIRED BY AN ALTERNATE METHOD OF INSTALLATION SHALL BE PAID TO THE RAIL COMPANY BY THE CONTRACTOR. THE COSTS FOR WATCHMEN OR FLAGGERS OCCASIONED BY THE NEGLIGENCE OF THE CONTRACTOR, OR ANY SUB-CONTRACTOR, IN CONNECTION WITH THE INSTALLATION OF THE PIPE OR CONDUIT SHALL BE PAID BY THE CONTRACTOR.

TRACK SUPPORTS REQUIRED BY THE RAIL COMPANY IN CONNECTION WITH THE INSTALLATION OF THE PIPE OR CONDUIT PER THE PLAN SHALL BE INCLUDED IN THE COMPANY FORCE ACCOUNT WORK AND PAID BY THE STATE. THE COST OF ANY TRACK SUPPORTS REQUIRED BY AN ALTERNATE METHOD OF INSTALLATION OF THE PIPE OR CONDUIT SHALL BE SHALL BE PAID TO THE RAIL COMPANY BY THE CONTRACTOR.

THE CONTRACTOR SHALL SECURE APPROVAL OF HIS OPERATIONS FROM THE STATE AND THE RAIL COMPANY. THE RAIL COMPANY WILL PERFORM AN ENGINEERING REVIEW OF METHODS OF OPERATIONS AND ENGINEERING SUPERVISION OF CONSTRUCITON WITHOUT COST TO THE CONTRACTOR.

PRIOR TO BIDDING, THE CONTRACTOR SHALL COORDINATE WITH THE RAIL COMPANY TO AGREE UPON THE REQUIREMENTS OF WATCHMEN AND FLAGGERS TO PROTECT RAILROAD TRAFFIC DURING THE CONTRACTOR’S OPERATIONS. THE CONTRACTOR SHALL EXECUTE A BOND IN FAVOR OF BOTH THE STATE AND THE COMPANY AS REQUIRED BY SECTION 5525.16 OF THE REVISED CODE OF OHIO.

THE CONTRACTOR SHALL CO-OPERATE WITH THE RAILROAD OFFICIALS CONCERNING WORK ADJACENT TO RAILROAD TRACKS, IN ORDER TO AVOID DELAY TO, OR INTERFERENCE WITH RAILROAD TRAFFIC, AND SHALL NOTIFY THE COMPANY ______ HOURS IN ADVANCE OF CONSTRUCTION OPERATIONS.

Designer Note: Provide this note when placing pipe culverts, sewers, or water lines under railroads. Through coordination with the railroad complete the ____hours that the railroad would like to be notified by.

D114 REVIEW OF DRAINAGE FACILITIES

BEFORE ANY WORK IS STARTED ON THE PROJECT AND AGAIN BEFORE FINAL ACCEPTANCE BY THE STATE, REPRESENTATIVES OF THE STATE AND THE CONTRACTOR, ALONG WITH LOCAL REPRESENTATIVES, SHALL MAKE AN INSPECTION OF ALL EXISTING SEWERS WHICH ARE TO REMAIN IN SERVICE AND WHICH MAY BE AFFECTED BY THE WORK. THE CONDITION OF THE EXISTING CONDUITS AND THEIR APPURTENANCE SHALL BE DETERMINED FROM FIELD OBSERVATIONS. RECORDS OF THE INSPECTION SHALL BE KEPT IN WRITING BY THE STATE.

ALL NEW CONDUITS, INLETS, CATCH BASINS, AND MANHOLES CONSTRUCTED AS A PART OF THE PROJECT SHALL BE FREE OF ALL FOREIGN MATTER AND IN A CLEAN CONDITION BEFORE THE PROJECT WILL BE ACCEPTED BY THE STATE.

ALL EXISTING SEWERS INSPECTED INITIALLY BY THE ABOVE MENTIONED PARTIES SHALL BE MAINTAINED AND LEFT IN A CONDITION REASONABLY COMPARABLE TO THAT DETERMINED BY THE ORIGINAL INSPECTION. ANY CHANGE IN THE CONDITION RESULTING FROM THE CONTRACTOR’S OPERATIONS SHALL BE CORRECTED BY THE

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CONTRACTOR TO THE SATISFACTION OF THE ENGINEER.

PAYMENT FOR ALL OPERATIONS DESCRIBED ABOVE SHALL BE INCLUDED IN THE CONTRACT PRICE FOR THE PERTINENT 611 CONDUIT ITEMS.

Designer Note: This note is to be used on projects where existing drainage facilities are to remain in service.

D115 UNRECORDED STORM WATER DRAINAGE

FURNISH A CONTINUANCE FOR ALL UNRECORDED STORM WATER DRAINAGE, SUCH AS ROOF DRAINS, FOOTER DRAINS, OR YARD DRAINS, DISTURBED BY THE WORK. FURNISH EITHER AN OPEN CONTINUANCE OR AN UNOBSTRUCTED CONTINUANCE BY CONNECTING A CONDUIT THROUGH THE CURB OR INTO A DRAINAGE STRUCTURE. THE LOCATION, TYPE, SIZE AND GRADE OF THE NEEDED CONDUIT TO REPLACE OR EXTEND AN EXISTING DRAIN WILL BE DETERMINED BY THE ENGINEER. ALL SUCH CONTINUANCE REQUIRES A RIGHT OF WAY USE PERMIT.

THE FOLLOWING CONDUIT TYPES MAY BE USED: 707.33, 707.41 NON-PERFORATED, 707.42, 707.43, 707.45, 707.46, 707.47, 707.51, 707.52 SDR35.

THE FOLLOWING ESTIMATED QUANTITIES HAVE BEEN INCLUDED IN THE GENERAL SUMMARY FOR USE AS DIRECTED BY THE ENGINEER FOR THE WORK NOTED ABOVE:

611, ______ “ CONDUIT, TYPE B, FOR DRAINAGE CONNECTION ______ FT.

611, ______ “ CONDUIT, TYPE C, FOR DRAINAGE CONNECTION ______ FT.

611, ______ “ CONDUIT, TYPE E, FOR DRAINAGE CONNECTION ______ FT.

611, ______“ CONDUIT, TYPE F, FOR DRAINAGE CONNECTION ______ FT.

Designer Note: This note is to be used only if there is a possibility that during construction there may be a need for additional continuance of storm water drainage from residential or commercial property. The designer shall make a complete investigation for the presence of existing storm water drainage from residential and commercial property. List quantities required for all located storm water drainage from residential and commercial property at the specific locations on the Plan & Profile sheets. All located storm water drainage from residential or commercial property is required to have a right of way use permit. If any such located storm water drainage from residential or commercial property do not have a right of way use permit then notice of such is required to be sent to the appropriate parities.

D116 UNRECORDED ACTIVE SANITARY SEWER CONNECTIONS

FURNISH A CONTINUANCE FOR ALL UNRECORDED ACTIVE SANITARY SEWER CONNECTIONS SUCH AS SANITARY, WASTEWATER, CURTAIN/GRADIENT DRAINS, AND FOUNDATION FLOOR DRAINS DISTURBED BY THE WORK. FURNISH AN UNOBSTRUCTED CONTINUANCE OF THE UNRECORDED ACTIVE SANITARY SEWER

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CONNECTIONS TO THE SATISFACTION OF THE ENGINEER. ALL SUCH CONTINUANCE REQUIRES A RIGHT OF WAY USE PERMIT. ALL SANITARY AND SANITARY WASTEWATER CONTINUANCE MAY ALSO REQUIRE A NPDES PERMIT FROM THE OHIO ENVIRONMENTAL PROTECTION AGENCY. REPORT ALL CONTINUANCE TO THE LOCAL HEALTH DEPARTMENT.

THE FOLLOWING CONDUIT TYPES MAY BE USED: 707.42, 707.43, 707.44, 707.45, 707.46, 707.47, 707.51, 707.52 SDR35, 706.01, 706.02, OR 706.08 WITH JOINTS AS PER 706.11 OR 706.12.

THE FOLLOWING ESTIMATED QUANTITIES HAVE BEEN INCLUDED IN THE GENERAL SUMMARY FOR USE AS DIRECTED BY THE ENGINEER FOR THE WORK NOTED ABOVE:

611, ______ “ CONDUIT, TYPE B, FOR SANITARY ______ FT.

611, ______ “ CONDUIT, TYPE C, FOR SANITARY ______ FT.

Designer Note: This note is to be used only if there is a possibility that during construction there may be a need for additional continuance of active sanitary sewer connections. The Designer shall make a complete investigation for the presence of active sanitary sewer connections. List quantities required for all active sanitary sewer connections at the specific locations on the Plan & Profile sheets. All located active sanitary sewer connections is required to have a right of way use permit. If any such located active sanitary sewer connections do not have a right of way use permit then notice of such is required to be sent to the appropriate parities. All sanitary and sanitary wastewater active sanitary sewer connections may also require a NPDES permit from the Ohio Environmental Protection Agency. Report all continuance to the local health department.

D117 MANHOLES, CATCH BASINS AND INLETS REMOVED OR ABANDONED

ALL CASTINGS SHALL BE CAREFULLY REMOVED AND STORED WITHIN THE RIGHT OF WAY FOR SALVAGE BY (STATE) (CITY) (VILLAGE) (COUNTY) FORCES.

PAYMENT FOR ALL OF THE ABOVE SHALL BE INCLUDED IN THE CONTRACT PRICE FOR THE PERTINENT 202 ITEM.

Designer Note: This note shall only be used where it has been determined that the owner desires to retain the existing castings.

D118 ITEM 511 WINGWALLS OR HEADWALLS FOR 611 ITEMS

FOR ITEMS 706.05, 706.051, 706.052 AND 706.053 WITH A CAST-IN-PLACE WINGWALL OR HEADWALL A PRECAST ALTERNATIVE MAY BE FURNISHED PER 602.03. THE PRECAST ALTERNATIVE WILL MEET THE CAST-IN-PLACE STRUCTURAL DESIGN LOADINGS, DESIGN HEIGHT, AND DESIGN LENGTH DIMENSIONS.

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FULL COMPENSATION FOR THE PRECAST WINGWALL OR HEADWALL IS THE NUMBER OF CUBIC YARDS OF ITEM 511 AND POUNDS OF ITEM 509 FOR THE CORRESPONDING CAST-IN-PLACE STRUCTURE.

Design Note: Include this note on all plans that have item 611, three-sided flat top, arch top, arches or box culverts that have an item 511 cast-in-place wingwall or headwall.

D119 ITEM SPECIAL- MISCELLANEOUS METAL

EXISTING CASTINGS MAY PROVE TO BE UNSUITABLE FOR REUSE, AS DETERMINED BY THE ENGINEER. IT SHALL BE THE CONTRACTOR’S RESPONSIBILITY TO PROVIDE THE CASTINGS OF THE REQUIRED TYPE, SIZE AND STRENGTH (HEAVY OR LIGHT DUTY) FOR THE PARTICULAR STRUCTURE IN QUESTION. ALL MATERIAL SHALL MEET ITEM 611 OF THE SPECIFICATIONS AND SHALL HAVE THE PRIOR APPROVAL OF THE ENGINEER.

THE FOLLOWING ESTIMATED QUANTITY HAS BEEN CARRIED TO THE GENERAL SUMMARY FOR USE AS DIRECTED BY THE ENGINEER.

SPECIAL, MISCELLANEOUS METAL _____ POUNDSTHE CONTRACTOR IS CAUTIONED TO USE EXTREME CARE IN THE REMOVAL, STORAGE AND REPLACEMENT OF ALL EXISTING CASTINGS. CASTINGS DAMAGED BY THE NEGLIGENCE OF THE CONTRACTOR, AS DETERMINED BY THE ENGINEER, SHALL BE REPLACED WITH THE PROPER NEW CASTINGS AT THE EXPENSE OF THE CONTRACTOR.

Designer Note: Use this note if existing castings are to be reused and which may be unsuitable.

D120 ITEM 611 - ( )”, SLOTTED DRAIN, TYPE ( )

THIS ITEM SHALL CONSIST OF ____ INCH DIAMETER SLOTTED DRAIN ALUMINUM COATED STEEL CONDUIT 707.01 WITH 6 INCH TRAPEZOIDAL GALVANIZED SOLID BAR GRATE AS APPROVED BY THE ENGINEER. ALL COSTS FOR LABOR AND MATERIALS, INCLUDING TYPE 2 BEDDING, AND BACKFILLING AS DETAILED ON STANDARD CONSTRUCTION DRAWING DM-1.3 SHALL BE INCLUDED IN THE PRICE BID PER FOOT FOR ITEM 611 - ____ “ SLOTTED DRAIN,TYPE ____ .

Designer Note: This plan note should be used in conjunction with Standard Construction Drawing DM-1.3. Outlet slotted drain pipe into a catch basin.

D121 ITEM SPECIAL - PIPE CLEANOUT

THIS WORK SHALL CONSIST OF REMOVING SEDIMENT AND DEBRIS FROM THE EXISTING DRAINAGE CONDUITS SPECIFIED IN THE PLANS. ALL MATERIAL REMOVED SHALL BE DISPOSED OF AS PER 105.16 AND 105.17. ALL SEWERS SHALL BE CLEANED OUT TO THE SATISFACTION OF THE ENGINEER.

CLEANOUT OF THE PIPE SHALL BE PAID FOR AT THE UNIT PRICE BID FOR ITEM SPECIAL - PIPE CLEANOUT. THIS PRICE SHALL INCLUDE THE COST FOR MATERIAL,

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EQUIPMENT, LABOR, AND ALL INCIDENTALS REQUIRED TO COMPLETE THE CLEANOUT.

THE FOLLOWING ESTIMATED QUANTITIES HAVE BEEN INCLUDED IN THE GENERAL SUMMARY FOR THE ABOVE NOTED WORK:

SPECIAL, PIPE CLEANOUT, 24” AND UNDER ________ FT.SPECIAL, PIPE CLEANOUT, 27” TO 48” ________ FT.SPECIAL, PIPE CLEANOUT, OVER 48” ________ FT.

Designer Note: This item may not be eligible for federal participation.

D122 ITEM 611 - CONDUIT MISC.: CURED-IN-PLACE PIPE LINER

INSTALL A CONTINUOUS (JOINT-LESS) CURED-IN-PLACE PIPELINER SYSTEM TO LINE THE INTERIOR OF THE HOST PIPE TO BE REHABILITATED. THE LINER PIPE MUST BE ABLE TO MOLD ITSELF OR FIT TIGHTLY TO THE SHAPE OF THE EXISTING PIPE. THE LINER MUST PROVIDE FOR COMPLETE STRUCTURAL INTEGRITY, INDEPENDENT OF THE LOAD BEARING CAPACITY OF THE EXISTING HOST PIPE. THE PIPELINER MUST BE CAPABLE OF CONFORMING TO THE PIPELINE BENDS IN THE HOST PIPE WITHOUT SPLITTING, RUPTURING, OR WRINKLING OF THE PIPE LINER MATERIAL. THE LINING MUST PROVIDE A FLOW CAPACITY EQUAL TO, OR GREATER THAN, THAT OF THE HOST PIPE PRIOR TO REHABILITATION. CURED-IN-PLACE PIPELINERS SHALL CONFORM TO ASTM D5813 AND BE DESIGNED ACCORDING TO ASTM F1216 AS A FULLY DETERIORATED GRAVITY PIPE. REFER TO SUPPLEMENTAL SPECIFICATION 833, SPECIFICALLY SECTION 833.04 ITEM 1. AND TABLES 833.01 AND 833.03 FOR THE DESIGN PARAMETERS.

INSTALLATION SHALL BE PER ASTM F 1216, ASTM F 1743, ASTM 2019 AND PER THE MANUFACTURER'S RECOMMENDATIONS. ALL PROCESS WATER AND CONDENSATE FROM STEAM USED IN THE INSTALLATION AND CURING PROCESS SHALL BE MANAGED PER 107.19 AS A LIQUID WASTE.

INSPECT THE EXISTING HOST PIPE USING EXPERIENCED PERSONNEL TRAINED IN LOCATING BREAKS, OBSTACLES, AND SERVICE CONNECTIONS BY CLOSED-CIRCUIT TELEVISION OR MAN ENTRY BEFORE AND AFTER INSTALLATION OF THE PIPELINER. CLEAN, REMOVE DEBRIS, AND REPAIR CONDUIT WALLS AND JOINTS PRIOR TO INSTALLING THE PIPELINER. RESTORE ACTIVE SERVICE CONNECTIONS AFTER INSTALLATION OF THE PIPELINER. PAYMENT FOR THE ABOVE WORK SHALL BE INCLUDED IN THE CONTRACT PRICE FOR ITEM 611, CONDUIT MISC.; CURED-IN-PLACE PIPE LINER.

Designer Note: Contact the Office of Hydraulic Engineering before specifying this item in the plans.

D123 EXISTING SUBSURFACE DRAINAGE

PROVIDE UNOBSTRUCTED OUTLETS FOR ALL EXISTING UNDERDRAINS OR AGGREGATE DRAINS ENCOUNTERED DURING CONSTRUCTION.

PROVIDE AN OUTLET PER STANDARD CONSTRUCTION DRAWING DM-1.1 FOR ALL UNDERDRAINS THAT OUTLET TO A SLOPE. UNDERDRAINS THAT CAN BE CONNECTED TO THE NEW OR EXISTING UNDERDRAINS AT THE END OF THE PROJECT LIMITS AS WELL AS ALL NECESSARY BENDS OR

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BRANCHES REQUIRED FOR CONNECTION ARE INCLUDED IN THE BASIS OF PAYMENT FOR UNCLASSIFIED PIPE UNDERDRAINS.

THE FOLLOWING ESTIMATED QUANTITIES HAVE BEEN INCLUDED IN THE GENERAL SUMMARY FOR THE WORK NOTED ABOVE:

601, TIED CONCRETE BLOCK MAT, TYPE 1 __________SQ. YD.605, AGGREGATE DRAINS __________FT.611__________” CONDUIT, TYPE F __________FT.611, PRECAST REINFORCED CONCRETE OUTLET __________EACH605__________” UNCLASSIFIED PIPE UNDERDRAINS __________FT.

Designer Note: The note is to be used on projects if there are existing underdrains or aggregate drains within the project limits that are to remain. The designer shall make a complete investigation for the presence of existing underdrain outlet locations or potential conflict areas within the project limits and show them on the plan view sheets.

D124 TEMPORARY DRAINAGE ITEMS

TEMPORARY DRAINAGE ITEMS LABELED ON THE MAINTENANCE OF TRAFFIC PLAN ARE ITEMIZED ON THE MOT PLANS. PAYMENT FOR THE TEMPORARY DRAINAGE ITEMS ARE ITEMIZED AND CARRIED TO THE GENERAL SUMMARY.

Designer Note: Provide this note when temporary drainage items are required in accordance to section 1010 of the L&D. Furnish drainage items for each phase of the maintenance of traffic operations. Removal items may be required between individual phases. Utilize drainage structures furnished for final drainage design where feasible.

E101 SEEDING AND MULCHING

THE FOLLOWING QUANTITIES ARE PROVIDED TO PROMOTE GROWTH AND CARE OF PERMANENT SEEDED AREAS:

659, SOIL ANALYSIS TEST ____ EACH659, TOPSOIL ____ CU. YD. 659, SEEDING AND MULCHING ____ SQ. YD. 659, REPAIR SEEDING AND MULCHING ____ SQ. YD. 659, INTER-SEEDING ____ SQ. YD. 659, COMMERCIAL FERTILIZER ____ TON 659, LIME ____ ACRES 659, WATER ____ M. GAL.659, MOWING ____ M. SQ. FT.

SEEDING AND MULCHING SHALL BE APPLIED TO ALL AREAS OF EXPOSED SOIL BETWEEN THE RIGHT-OF-WAY LINES, AND WITHIN THE CONSTRUCTION LIMITS FOR AREAS OUTSIDE THE RIGHT-OF-WAY LINES COVERED BY WORK AGREEMENT OR SLOPE EASEMENT. QUANTITY CALCULATIONS FOR SEEDING AND MULCHING ARE BASED ON THESE LIMITS.

Designer Note: The above quantities should be used on all projects that require grading work. The following is a basic guideline for estimating quantities for the above items. These quantities may be omitted from the note if they are itemized elsewhere in the plan. Calculations for all items should be shown in the plans.

659, Soil Analysis Test (Each)Soil Analysis Tests are used to field adjust the rate of Lime based on soil conditions.A. Soil Analysis Test is not specified.

1. The standard rate for Lime will be used without adjustment.

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B. Soil Analysis Test is specified. If specified, minimum of two tests.1. If no Topsoil to be placed - One test per 10 Acres (one test per 48400 Sq. Yd.) of

permanent seeded area and sodded area.2. If placing Topsoil - One test per 10000 Cu. Yds. of Topsoil.

659, Topsoil (Cu. Yd.)111 Cu. Yds. per 1000 Sq. Yd. of permanent seeded area. Topsoil is optional. However, it is recommended, especially for projects involving A4 silty materials, granular embankment or granular materials due to severe erosion problems.

659, Seeding and Mulching (Sq. Yd.)This quantity is usually calculated by the end width method using the cross sections. On short projects, seeding quantities may be determined by other methods. For example, the area for seeding may be estimated by calculating an area per Plan & Profile sheet determined by multiplying an average width (based on construction limits or right-of -way lines) by the distance on each sheet, and then deducting for paved surface areas. A deduction should be taken for 660 and 670 items.

659, Repair Seeding and Mulching (Sq. Yd.) 5 % of the permanent seeding and mulching area.

659, Inter-seeding (Sq. Yd.)5% of the permanent seeding and mulching area.

659, Commercial Fertilizer (Ton)30 pounds per 1000 Sq. Ft. ( one Ton per 7410 Sq. Yd.) of permanent seeded area. This rate includes 20 pounds per 1000 Sq. Ft. for the first application and 10 pounds per 1000 Sq. Ft. for the second application. If Inter-seeding is provided, use an additional 20 pounds per 1000 Sq. Ft. of commercial fertilizer for the Inter-seeding area.

659 Lime (Acre)Apply over permanent seeded area.

659, Water (M. Gal.)Two applications each at 300 Gallons per 1000 Sq. Ft. (0.0027 M Gallons per Sq. Yd.) of permanent seeded area. The above rate is for a single application. If Inter-seeding is provided, use an additional 300 Gallons per 1000 Sq. Ft. of water for the Inter-seeded area.

659, Mowing (M. Sq. Ft.)25 % of the permanent seeded area for projects expected to last more than one construction season.

E102 SODDING

THE FOLLOWING QUANTITIES ARE PROVIDED TO PROMOTE GROWTH AND CARE OF PERMANENT SODDED AREAS.

659, SOIL ANALYSIS TEST ____ EACH659, TOPSOIL ____ CU. YD. 659, COMMERCIAL FERTILIZER ____ TON 659, LIME ____ ACRE 659, WATER ____ M. GAL. 660, SODDING, UNSTAKED, STAKED, REINFORCED ____ SQ. YD.

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Designer Note: The above quantities should be used on all projects that have pay item(s) for permanent sodding. The following is a basic guideline for estimating quantities for the above items. These quantities may be omitted from the note if they are itemized elsewhere in the plan. Calculations for all items should be shown in the plans.

659, Soil Analysis Test (Each)Soil Analysis Tests are used to field adjust the rate of Lime based on soil conditions. C. Soil Analysis Test is not specified.

1. The standard rate for Lime will be used without adjustment.D. Soil Analysis Test is specified. If specified, minimum of two tests.

1. If no Topsoil to be placed - One test per 10 Acres (one test per 48400 Sq. Yd.) of permanent sodded area.

2. If placing Topsoil - One test per 10000 Cu. Yds. of Topsoil.

659, Topsoil (Cu. Yd.)111 Cu. Yds. per 1000 Sq. Yd. of permanent sodded area. Topsoil is optional. However, it is recommended, especially for projects involving A4 silty materials, granular embankment or granular materials due to severe erosion problems.

659, Commercial Fertilizer (Ton)30 pounds per 1000 Sq. Ft. (one Ton per 7410 Sq. Yd.) of permanent sodded area. This rate includes 20 pounds per 1000 Sq. Ft. for the first application and 10 pounds per 1000 Sq. Ft. for the second application.

659, Lime (Acre)Apply over permanent sodded area.

659, Water (M. Gal.)1 application every 7 days for an additional 2 months beyond the requirements of 660.09. The rate shall be 300 gallons per 1000 Sq. Ft. (0.0027 M. Gallons per Sq. Yd.) of permanent sodded area.

660, Sodding (Sq. Yd.)This is the actual number of Sq. Yds. of permanent sodded area.

W99 POST CONSTRUCTION STORM WATER TREATMENT

THIS PLAN UTILIZES STRUCTURAL BEST MANAGEMENT PRACTICES (BMP’S) FOR POST CONSTRUCTION STORM WATER TREATMENT.

Designer Note: This plan note shall be used on all projects that have post construction storm water management BMP’s. The note shall be followed by the below notes if applicable.

W101 BIORETENTION CELL(S)

CONSTRUCT THE BIORETENTION CELL(S) AFTER ALL CONTRIBUTING DRAINAGE AREAS ARE STABILIZED AS SHOWN ON THE CONTRACT PLANS. DO NOT OPERATE HEAVY EQUIPMENT WITHIN THE PERIMETER OF A BIORETENTION CELL. USE ALL SUITABLE EXCAVATED MATERIAL IN THE WORK. ALTERNATIVELY, LEGALLY USE, RECYCLE, OR DISPOSE OF ALL EXCAVATED MATERIALS ACCORDING TO 105.16 AND 105.17.

EXCAVATE THE BIORETENTION CELLTO THE DIMENSIONS, WITH VERTICAL SIDES, TO THE ELEVATIONS SPECIFITIED. MINIMIZE THE COMPACTION OF THE BOTTOM OF THE BIORETENTION CELL. EXCAVATION WILL BE MEASURED AND PAID AS ITEM 203,

Appendix B – Sample Plan Notes

April 2017

EXCAVATION APP. ENSURE THAT ONLY VERTICAL SIDES ARE CONSTRUCTED AND BE INCLUDED IN ITEM 203 EXCAVATION. THE BIORETENTION CELL CONSISTS OF FOUR DISCRETE LAYERS: BIORETENTION PLANTING SOIL LAYER, FINE AGGREGATE LAYER, COARSE AGGREAGE NO. 78 LAYER, AND COARSE AGGREGATE NO. 57 LAYER AND AN UNDERDRAIN SYSTEM. THE MATERIALS AND VOLUMES FOR EACH LAYER ARE AS SHOWN:

BIORETENTION CELL PROJECT QUANTITY (CY)

BIORETENTION PLANTING SOIL LAYER PLUS 3 INCH COVERCOMPOSITION BY VOLUME

5 PARTS SAND – CMS FINE AGGREGATE AS PER 703.201 PART TOPSOIL – CMS 659.052 PARTS COMPOST – CMS 659.06

FINE AGGREGATE AS PER CMS 703.20COARSE AGGREAGE SIZE NO. 78 PER 703.20COARSE AGGREAGE SIZE NO. 57 PER 703.20TOTAL CUBIC YARDS

CONSTRUCT THE UNDERDRAIN SYSTEM AS SPECIFIED.

PLACE THE BIORETENTION PLANTING SOIL IN 12 INCH LIFTS. THE BIORETENTION PLANTING SOIL LAYER PLUS 3 INCH COVER IS 3 INCHES GREATER THAN THE DEPTH SPECIFIED TO ACCOUNT FOR EXPECTED SETTLING OF THE UNCOMPACTED SOIL.

THE BIORETENTION PLANTING SOIL SHALL BE A UNIFORM MIX THAT IS FREE OF STONES, STUMPS, ROOTS, OR ANY OTHER OBJECT LARGER THAN TWO INCHES. THE SOIL MAY CONSIST OF EXISTING SOIL, FURNISHED SOIL, OR A COMBINATION OF BOTH PROVIDED THAT THE PH IS BETWEEN 5.2 – 8.0 AND MEETS THE COMPOSITION REQUIREMENTS LISTED ABOVE. PHOSPHORUS CONCENTRATIONS OF THE PLANTING SOIL SHALL FALL BETWEEN 15 AND 60 MG/KG (PPM) AND DETERMINED BY THE MEHLICH III TEST.

THOROUGHLY MIX THE BIORETENTION PLANTING SOIL PRIOR TO PLACEMENT.

PLACE OBSERVATION WELL AND CLEANOUT WHERES PECIFIED. CONNECT THE OBSERVATION WELL AND CLEANOUT TO THE PERFORATED UNDERDRAIN WITH THE APPROPRIATE MANUFACTURED CONNECTIONS. EXTEND THE OBSERVATION WELL AND CLEANOUT 4 INCHES ABOVE THE SURFACE ELEVATION. CAP THE OBSERVATION WELL AND CLEANOUT WITH A PVC THREADED SCREW CAP. CAP THE ENDS OF PERFORATED UNDERDRAIN PIPES NOT TERMINATING IN AN OBSERVATION WELL AND CLEANOUT OR CONNECTED TO OTHER CONDUITS.PLACE SEED, TURF, TREES, SHRUBS, OR OTHER PLANT MATERIALS FOR BIORETENTION FACILITIES AS SPECIFIED. PLANT MATERIALS WILL BE MEASURED AND PAID FOR PER CMS ITEM(S) 659, 660, OR 661 DEPENDING ON THE PLANT MATERIALS SPECIFIED. APPLY NO PESTICIDES, HERBICIDES, LIME, AND FERTILIZERS. INSTALL ITEM 671 AS SPECIFIED. INSTALL ITEM 611 AS SPECIFIED

BIORETENTION CELLS WILL BE PAID FOR AS ITEM 601, BIORETENTION CELL CU YD. AND ITEM 601, TIED CONCRETE MAT SQ YD. EXCAVATION FOR BIORETENTION CELLS SHALL BE FOR VERTICAL SIDES ONLY AS SPECIFIED AND PAID FOR AS ITEM 203, EXCAVATION APP CU YD. PERFORATED UNDERDRAINS, OBSERVATION WELLS, AND ASSOCIATED FITTINGS AND COUPLERS WILL BE PAID FOR AS ITEM 605, UNDERDRAIN APP. NON PEFORATED OUTLET PIPES FOR BIORETENTION CELLS SHALL BE PAID FOR AS ITEM 611. SEEDING AND MULCHING FOR THE BIORETENTION

Appendix B – Sample Plan Notes

April 2017

CELL SHALL BE PAID FOR AS ITEM 659 SEEDING AND MULCHING SQ YD. EROSION CONTROL MATS SHALL BE PAID FOR AS ITEM 671, EROSION CONTROL MATS SQ YD.

Designer Note: This plan note shall be used on all projects that have bioretention cell(s) identified in the plan.

Add plan note that states: “ITEM 203, EXCAVATION, APP VERTICAL SIDES ONLY” on plan sheets showing bioretention cell cross section.

W102 INFILTRATION TRENCH (OR BASIN)

THIS PLAN UTILIZES INFILTRATION FOR POST CONSTRUCTION STORM WATER TREATMENT. CONSTRUCT THE COMPLETED INFILTRATION TRENCH(ES) (AND OR BASIN(S)) AFTER ALL CONTRIBUTING DRAINAGE AREAS ARE STABILIZED AS SHOWN IN THE CONTRACT PLANS AND TO THE SATISFACTION OF THE ENGINEER. DO NOT USE INFILTRATION DEVICES AS TEMPORARY SEDIMENT CONTROL FACILITIES DURING CONSTRUCTION. DO NOT OPERATE HEAVY EQUIPMENT WITHIN THE PERIMETER OF AN INFILTRATION DEVICE DURING EXCAVATION OR BACKFILLING OF THE FACILITY.

Designer Note: This plan note shall be used on all projects that have infiltration trenches and or basins identified in the plan. Embankment work to create the impoundment will be constructed and paid for as Item 203 Embankment, using natural soils, 703.16.A.

W103 MANUFACTURED WATER QUALITY STRUCTURE

THIS PLAN UTILIZES MANUFACTURED WATER QUALITY STRUCTURES FOR WATER QUALITY TREATMENT. AREAS HAVE BEEN SHOWN IN THE PLANS FOR PLACEMENT OF AN OFF-LINE SYSTEM. PAYMENT FOR THESE DEVICES SHALL BE MADE AT THE CONTRACT UNIT PRICE FOR ITEM 895, MANUFACTURED WATER QUALITY STRUCTURE, TYPE ____.

Designer Note: This plan note shall be used on all projects that have manufactured water quality structures identified in the plan. If more than one manufactured water quality structure is provided in the plans, a table shall be provided to indicate the location and type of each structure used. Supplemental specification 895 outlines the different types of structures (1-4). Manufactured systems may not be used without approval of the Hydraulics Section through a feasibility study. Contact the Hydraulics Section for an area dimension that shall be shown in the plan.