Update on the Stormwater Permitting Program Megan Moir Water Quality Division
Dec 22, 2015
Update on the Stormwater Permitting Program
Megan Moir Water Quality Division
Stormwater Permit Programs
Operational
Impervious Surface
(a.k.a. State Stormwater Permits, 9015, INDS)
Construction
Disturbed Soil
(a.k.a. CGP, 9001, 9020, INDC)
MS4
“Big picture” permit for concentrated
population centers
Multi-Sector
“Industrial” facilities
(a.k.a. industrial permit MSGP, 9003)
State Stormwater PermitJurisdictional Thresholds
Thresholds are based on area of impervious surface Impervious = man made surfaces, including, but not limited to, paved
and unpaved roads, parking areas, roofs, driveways and walkways from which precipitation runs off rather than infiltrates.
A State Stormwater Discharge Permit is required for projects which involve: New impervious ≥ 1 acre; Redevelopment of existing impervious ≥ 1 acre. Expansions with ≥ 1 acre total resulting impervious surface
(existing/redevloped + new), unless qualify for exemption expansion < 5000 sf and cumulative expansions since 7/4/2005 < 5000 sf
Thresholds are applied to the common plan of development, not individual phases!!!
State Stormwater Discharge Permits
Are you constructing new impervious or redeveloping existing impervious surfaces? If you are doing both, examine jurisdiction for each type.
Redevelopment of Existing Impervious Surface
Does the surface being redeveloped have an existing, valid stormwater permit?
yes
No additional permit is necessary, but no matter how much you are redeveloping, you must provide the same or better level of treatment that was in the previous permit. Please submit plans of redevelopment to be included in previous permit
file. *
Are you redeveloping ≥ 1 acre?
Must obtain a 9015 permit; must reduce impervious surface by 20% of area you are redeveloping or provide treatment for 20% of the WQv from the redeveloped
area. *
no
yes
New Impervious Surface
Are you constructing > 5000 s.f of impervious?
Has there been any construction of impervious since 7/4/2005?
Will the amount you are constructing plus what has been built since 7/4/2005 exceed 5000 s.f.?
no
no
yes
yes
Is there any existing impervious in the project or on some related parcel (see “total resulting”)?
yes
no
Is the total resulting (new + existing/redeveloped) impervious surface ≥ 1 acre?
yes
You must obtain coverage under a State Discharge Permit for these new surfaces by demonstrating compliance with the 2002 VT Stormwater Management Manual; existing surfaces that were previously permitted must still receive the same treatment as in their original permit. Changes to previously permitted existing surfaces should be submitted for review.
No permit necessary for new surfaces; existing surfaces that were previously permitted must still receive the same treatment as in their original permit. Changes should be submitted for review.
no
You must obtain coverage for the new surfaces under a State Discharge permit by demonstrating compliance with the 2002 VT Stormwater Management Manual.
yes
Are you constructing ≥ 1 acre of new impervious?
yes no
*These areas still count towards your total resulting impervious when dealing with impervious expansions!
no
No permit necessary
no
Do I need to obtain a State Stormwater Discharge Permit?Permitting Flow Chart for Stormwater Discharges from Impervious Surfaces to Waters not Impaired by Stormwater
Permitting thresholds are the same for discharges from impervious surfaces to waters impaired by stormwater. However, the process of obtaining a permit is more complicated. Projects in impaired watersheds should refer to Chapter 22 and/or contact the Stormwater Section.
New impervious ≥ 1 acre
1 ac impervious
Permit REQUIRED!
Remember, the determination must take into account all impervious in common plan of development
Phased development must be looked at as a whole
Undeveloped Land
State Stormwater Discharge Permits
Redevelopment ≥ 1 acre of existing impervious
0.75 ac impervious in footprint of original impervious
1.0 ac impervious in footprint of original impervious
Permit NOT required!
Permit REQUIRED!
But obtaining permit is not as involved – only have to treat 20% of the Water Quality Volume or remove an amount of existing impervious equivalent to 20% of the redeveloped area.
State Stormwater Discharge Permits
"Redeveloped impervious": the reconstruction of an impervious surface where an impervious surface currently exists, when such reconstruction involves substantial site grading, substantial subsurface excavation, or modification of existing stormwater conveyance. Redevelopment does not mean management activities on impervious surfaces, including any crack sealing, patching, cold-planing, resurfacing, paving a gravel road, reclaiming, or grading treatments used to maintain pavement, bridges and unpaved roads. Redevelopment does not include expansions.
Expansions: “Total Resulting Impervious”
For purposes of determining whether or not an expansion of existing impervious will require a Stormwater discharge permit, the following apply: Existing impervious, and total resulting impervious shall include all impervious
area within the parcel on which the subject activity is taking place, and the impervious area on other parcels linked by a common plan of development. A common plan of development includes large projects, and subdivisions, the operation or creation of which required or requires state or local permits related to either the regulation of land use or discharge to state waters.
State Stormwater Discharge Permits
Expansions: “Total Resulting Impervious”
For example, determinations must examine the existing impervious on all parcels that are under the jurisdiction of landuse permits such as an Act 250 permit, parcels that share common infrastructure (wastewater, roads, water supply etc), or parcels that are in some other way part of a discernible common plan of development. i.e. someone subdivides their property into two lots, one of which contained a
house and driveway, and then later subdivided the second lot into multiple lots that were going to be sold for home construction.
State Stormwater Discharge Permits
Expansions: “Total Resulting Impervious”
One would need to consider both the new impervious as well the existing impervious on the other parcel that was part of the Act 250 process. If not Act 250 permit was involved, the common plan of development might be indicated by a shared private road serving all homes including the existing home, or a shared water/wastewater system.
The new impervious is considered an expansion to the original impervious on the original lot, and the existing impervious must be counted as part of the “total resulting impervious”.
New impervious = 0.95 acres Existing impervious = 0.10 acres Total resulting = 1.05 acres
Thus a permit is required for the expansion!
No treatment is required for the existing impervious.
State Stormwater Discharge Permits
Expansions: “Total Resulting Impervious”
For purposes of determining whether or not an expansion of existing impervious will require a Stormwater discharge permit, the following apply: Existing impervious, and total resulting impervious shall include all impervious
area within the parcel on which the subject activity is taking place, and the impervious area on other parcels linked by a common plan of development. A common plan of development includes large projects, and subdivisions, the operation or creation of which required or requires state or local permits related to either the regulation of land use or discharge to state waters.
For highway/linear projects, the total resulting impervious shall include all impervious surface with the project limits.
e.g.
expansion
project limits
State Stormwater Discharge Permits
Allen Brook
Englesby Brook
Munroe Brook
Bartlett Brook
Indian Brook
Potash Brook
Centennial Brook
Morehouse Brook
Sunderland Brook
Rice Brook
Clay Brook
Moon Brook
Roaring Brook
East Branch of Roaring Brook
N. Branch of Deerfield
STORMWATER IMPAIRED WATERSHEDS
State Stormwater Discharge Permits
Jurisdictional thresholds are the same, but sediment load calculations are required in addition to meeting 2002 VSWMM - see Chapter 22 of the Stormwater Rule for more information
Overview of the 2002 Vermont Stormwater Management Manuals (VSWMM)
Unified Sizing Criteria Water Quality Channel Protection Groundwater Recharge Overbank Flood Protection Extreme Flood Protection
Pre-Approved STP Designs Required Design Elements Design Guidance Cold Climate Required Elements
and Design Advice
Site Design Credits
Volume I – SW Treatment Standards
Now in our 5th printing!
State Stormwater Discharge Permits
Overview of the 2002 Vermont Stormwater Management Manuals (VSWMM)
Site Design and Landscaping Selecting the most effective stormwater
treatment system Landscaping Guidance and Plant Lists
STP Construction Specs Construction specifications for infiltration, sand
filters, bioretention and open channels
Design Examples 5 complete design examples
Assorted Design Tools Miscellaneous Technical References
Volume II – Technical Guidance
State Stormwater Discharge Permits
Water Quality Treatment
Goal: Capture and treat 90% of the annual runoff producing events generated by the site Treat = use an approved structural (i.e. pond, filter, infiltration basin)
or non-structural (i.e. disconnection) practice which has been shown to remove 80% TSS and 40% TP
Provide treatment for the entire site’s runoff up to the 0.9” storm
Water Quality Volume (WQv) = (0.9*Rv*A)/12 where: A = site area (impervious + disturbed pervious) Rv = 0.05+0.009I (I = % impervious)
Minimum WQv = 0.2 watershed inches
State Stormwater Discharge Permits
Amount of impervious area is largest contributor
WQv formula simplifies to:
0.00375A + 0.0675(IA), where IA = impervious area (acres)
Water Quality Treatment
Typical STPs Ponds Wetlands Infiltration Systems Filters (including Bioretention) Grass Swales (specially designed)
Treatment practices included in Volume I of the 2002 SWMM are identified as providing 80% removal of TSS and 40% removal of TP
State Stormwater Discharge Permits
Groundwater Recharge Goal: To preserve existing water table elevations by maintaining the average annual
recharge rate for the site Replicate pre-development recharge through a standard based upon the annual average
recharge of the site’s existing Hydrologic Soil Groups (i.e. no recharge required for D soils)
Table 2.2 in the VSWMM manual lists acceptable stormwater treatment practices for recharge
State Stormwater Discharge Permits
0.00
0.05
0.10
0.15
0.20
0.25
0.30
0.35
0.40
0.45
0 10 20 30 40 50 60 70 80 90 100Site Imperviousness [%]
Rec
har
ge
Vo
lum
e [W
ater
shed
Inch
es]
A Soils
D Soils
C Soils
B Soils
Site Design Credits
Site Design Credits are often used to meet Water Quality and Recharge Requirements
Currently Approved Site Design Credits Conservation Areas Disconnection Stream Buffers Grass Channels Environmentally Sensitive Rural Development
Pay careful attention to each of the criteria that must be met in order to qualify for these credits Slope Land-use/density Contributing length : treatment length, etc.
Slope requirements
Slope and land-use requirements
State Stormwater Discharge Permits
Channel Protection
Goal: Protect downstream receiving channels from degradation
Provide 12 or 24 hour detention of site runoff from the 1 year – 24 hour storm (approximately 2.1 - 2.3 inches in Vermont) 12 hour detention for cold water
receiving streams 24 hour detention for warm water
receiving streams or wetlands
Waived for sites With < 1 acre of expansion; With < 2 cfs of discharge; or Discharging to waterbody with > 10 sq.
mi. drainage area
State Stormwater Discharge Permits
Channel Protection: CPv
Qcrt
Qpost –higher Q and larger Vr
Qpre
Qcrt
Qpre
Qpost-controlled
Providing peak discharge control DOES NOT meet CPv The goal is to release runoff gradually so that critical erosive flows/velocities
(Qcrt) will seldom be exceeded downstream. The extended detention is used as a surrogate for the more involved Distributed
Runoff Control method (Appendix D9, 20 pgs long), which is the more involved method of determining the appropriate channel protection release rate.
Q Q
TimeTime
Overbank Flood Protection (Qp10)
Goal: Protection of downstream infrastructure from an increase in the frequency and magnitude of overbank flooding
Provide storage to control the peak discharge of the post developed runoff volume from the 10-year, 24-hour storm (ranges from 3.1 to 4.0 inches in Vermont ) by releasing at the pre-development runoff rate.
Qp10 may be waived for projects where: Discharges to receiving waters with drainage areas greater than 10 sq.
miles; or Site is smaller than 5 acres AND channel has capacity to convey the
post development discharge downstream to the point of the 10% rule
State Stormwater Discharge Permits
Extreme Flood Protection (Qp100)
Goal: Prevent flood damage from infrequent but very large storm events, maintain the boundaries of the predevelopment 100-year floodplain, and protect the physical integrity of a stormwater management practice itself
Provide storage to control the peak discharge rate of the post development runoff volume from the 100-year, 24‑hour storm (ranges from 5.0 – 6.8 inches in Vermont) by releasing at the predevelopment runoff rate.
Qp100 may be waived for projects where: Discharges to receiving waters with drainage areas greater than 10 sq.
miles; or Impervious acreage < 10 acres; or A downstream analysis is conducted that indicates extreme flood
control is not necessary
State Stormwater Discharge Permits
Demonstrating Compliance
Design standards Water Quality
Pre-treatment: largely to reduce maintenance frequency Treatment: Standards linked to unit processes of different
types of practices, e.g.:– Ponds: settling/sedimentation; biologic processes– Infiltration– Grass Channels: sedimentation– Filters: physical filtration and/or sorption depending on media– NEED TO KNOW HOW EACH PRACTICE WORKS TO DESIGN
EFFECTIVE TREATMENT
Water Quantity Runoff models with detention components.
Importance of Models
Construction Stormwater Permitting in Vermont - Overview
Since 2002, 5 acre+ projects have required permits
New General Permit issued September 13, 2006 for 1 acre+ disturbance projects, replaces original permit
Required by Federal Clean Water Act and National Pollutant Discharge Elimination System Phase II (NPDES)
Includes smaller projects part of larger common plan of development
Construction Stormwater Permitting in Vermont - Overview
Winter Construction Winter Oct 15-Apr 15
Requires notification of planned work, implementing standard winter EPSC measures, including: Daily mulching (unless work is in a self contained trench and/or no
precipitation is forecast for the next 24 hours) Double the mulching rate
Construction Stormwater Discharge Permits
Construction Stormwater Permitting in Vermont-Filing Applications
CGP Eligibility determined by Risk of Sediment Discharge and receiving water sensitivity Type of Waters (impaired, Outstanding Resource) Extent of Disturbance (2 acres, 5 acres, 7 acres) Duration of Disturbance (7, 14, or 21 days) Slopes and Soils Presence/absence of Vegetated Buffers Work within resource buffer
Construction Stormwater Discharge Permits
3 Permitting Possibilities:
1. Low Risk2. Moderate Risk3. Individual Permit
Construction Stormwater Permitting in Vermont-Filing Applications
Eligible for General Permit
Construction Stormwater Discharge Permits
Construction Stormwater Permitting in Vermont – Filing Applications
Risk EvaluationRisk Evaluation Series of Yes/ No, Q/A Focused on Erosion Prevention Encourages voluntary phasing,
prompt stabilization, use of vegetated buffers
If project is not automatically low risk, then must do detailed evaluation comparing risk factors and risk mitigation factors.
Construction Stormwater Discharge Permits
Construction Stormwater Permitting in Vermont – Filing Applications
Basic Risk EvaluationBasic Risk EvaluationProject is automatically Low Risk if meet all of the
following:1. < 2 acres2. 50 ft vegetated buffer3. 14 days maximum disturbance in any area before temporary
or permanent stabilization4. Not discharging to special class of water
Construction Stormwater Discharge Permits
Construction Stormwater Permitting in Vermont – Filing Applications
Low Risk ProjectsLow Risk ProjectsSubmit Notice of IntentAgree to implement Low Risk Guide ~10 days to authorizationValid for 2 years
Construction Stormwater Discharge Permits
Construction Stormwater Permitting in Vermont – Filing Applications
Low Risk HandbookLow Risk Handbook Common practices Basic use Suited to low risk
construction
Construction Stormwater Discharge Permits
Construction Stormwater Permitting in Vermont – Filing Applications
Once AuthorizedOnce Authorized Receives Notice of
Authorization Lists all voluntary limits Posted at site for public and
inspector reference, remind permittee
Construction Stormwater Discharge Permits
Construction Stormwater Permitting in Vermont – Filing Applications
Moderate Risk ProjectsModerate Risk Projects Submit Notice of
Intent Site specific EPSC
plan with EPSC Summary Forms
Construction Stormwater Discharge Permits
Construction Stormwater Permitting in Vermont – Filing Applications
Once AuthorizedOnce Authorized Receives Notice of
Authorization for posting Receives OSPC Handbook Receives Field Guide
Construction Stormwater Discharge Permits
Construction Stormwater Permitting -Field Implementation-
On-Site Plan Coordinator in charge of compliance
Weekly & Post-Runoff Inspections Discharge Reports Track Amendments On-Site Plan Coordinator Handbook
Construction Stormwater Discharge Permits
Construction Stormwater Permitting in Vermont – Filing Applications
Projects Requiring Projects Requiring Individual PermitIndividual Permit
Submit Application Site specific EPSC plan Usually WQ
monitoring, EPSC specialist oversight
Construction Stormwater Discharge Permits
General ApproachGeneral Approach Minimize Minimize
disturbancedisturbance Manage runoffManage runoff Stabilize Stabilize
promptlypromptly Establish Establish
VegetationVegetation
Erosion Prevention and Sediment Control Erosion Prevention and Sediment Control PlanPlan
Construction Stormwater Discharge Permits
Frequent mulchingFrequent mulching
EPSC- StabilizationEPSC- Stabilization
Construction Discharge Permits
Silt fenceSilt fence Show silt fence on EPSCP sheet as it should be - ON THE CONTOUR!Show silt fence on EPSCP sheet as it should be - ON THE CONTOUR! Inspection and maintenance are a must!Inspection and maintenance are a must!
Silt fence should NOT be used for demarcation of the limits of disturbance!Silt fence should NOT be used for demarcation of the limits of disturbance!
EPSC- Perimeter ControlEPSC- Perimeter Control
Construction Stormwater Discharge Permits
EPSC- Perimeter ControlEPSC- Perimeter Control
Construction Stormwater Discharge Permits
Multi-Sector General Permit for Stormwater
Discharges Associated with Industrial Activities
(3-9003)
Christy WittersDEC Stormwater Section
www.vtwaterquality.org/stormwater.htm
(802) 241-3777
MSGP Outline
Purpose Who requires MSGP coverage Types of MSGP coverage
No Exposure Conditional Exclusion Notice of Intent (NOI)
Due dates for applying Application review procedure
MSGP Overview
Goal: Prevent pollution from industrial activities VT MSGP signed August 18, 2006 5 year National Pollutant Discharge Elimination
System (NPDES) permit required by Federal law Requires facilities that have industrial materials
or activities exposed to stormwater to: Prepare a Stormwater Pollution Prevention Plan
(SWPPP) Monitor outfalls for potential pollutants
Regulated Activities
Industrial facilities SIC code of the facility’s primary activity is
listed in Table D-1 of the permit
Regulated Activities Any facility with one of the following activities on site:
Stormwater discharges with specific effluent limitations (Table 1-1)
Types of MSGP coverage
No Exposure Conditional Exclusion Certify that the facility meets the No
Exposure conditions Permit Coverage
Submit Notice of Intent Prepare Stormwater Pollution Prevention
Plan (SWPPP) Implement Best Management Practices
(BMPs) Conduct Monitoring
No Exposure
No Exposure All materials and activities are protected by a
storm resistant shelter to prevent exposure to rain, snow, snowmelt, and/or runoff
Storm resistant shelter
No Exposure Materials that may be stored outdoors
Final products intended for outdoor use & not deteriorating
Lidded dumpstersAbove Ground Storage Tanks not associated with vehicle maintenance
Adequately maintained vehicles
Sealed drums, barrels, tanks without operational taps or valves; not deteriorating
Types of MSGP coverage
Full Application for coverage Notice of Intent (NOI) – application form
Prepare and implement Stormwater Pollution Prevention Plan (SWPPP)
• Best Management Practices (BMPs) Behavioral and Structural BMPs
Conduct stormwater monitoring
Application deadlines
No Exposure – immediately NOI
Existing facilities – immediately New facilities – 90 days prior to commencing
activities SWPPP
Existing facilities – May 15, 2007 New facilities – 90 days prior to commencing
activities
Application Review Procedure No Exposure
Applications checked for completeness and approved
NOI Applications checked for completeness 10 Day Public Comment Period Activity authorized under the permit
SWPPP Reviewed when they are received Expecting most SWPPPs near May 15
deadline
Eight municipalities (Burlington, Essex, Essex Jct, Milton, Shelburne, South Burlington, Williston and Winooski
Three “non-traditional” (systems owned or operated by UVM, Burlington International Airport and VTRANS)
Municipal Separate StormwaterMunicipal Separate Stormwater SystemsSystems
(MS4)(MS4)
MS4 Permits
MS4 6 Minimum MeasuresMS4 6 Minimum Measures
1. Public Education and Outreach www.smartwaterways.org
2. Public Participation and Involvement
3. Illicit Discharge and Detection Elimination
4. Construction Site Runoff Control
5. Post-construction Site Runoff Control
6. Pollution Prevention / Good Housekeeping
MS4 Permits
For questions, contact Jim Pease at VT SWMP