CHESAPEAKE BAY POLLUTANT REDUCTION PLAN FOR DERRY TOWNSHIP MUNICIPAL AUTHORITY · 2017-07-28 · Chesapeake Bay Pollutant Reduction Plan DTMA, Derry Township, Dauphin County, PA Page
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Introduction The following Chesapeake Bay Pollutant Reduction Plan (CBPRP) addresses how the Derry Township Municipal Authority, Dauphin County, Pennsylvania intends to achieve the pollutant reduction requirements prescribed by the Pennsylvania Department of Environmental Protection (PADEP) in the Municipal MS4 Requirements Table1.
This document was prepared following the guidance provided in the Pennsylvania Department of Environmental Protection (PADEP), National Pollutant Discharges Elimination System (NPDES) Stormwater Discharges from Small Municipal Separate Storm Sewer Systems Pollutant Reduction Plan (PRP) Instructions2.
GENERAL INFORMATION
Permittee Name:
Derry Township Municipal Authority
NPDES Permit No.: PAG133637 A-1
Mailing Address: 670 Clearwater Road Effective Date: March 1, 2017
City, State, Zip: Hershey, PA, 17033 Expiration Date: March 15, 2018
MS4 Contact Person: Michael Callahan Renewal Due Date: September 16, 2017
Title: Stormwater Program Coordinator Municipality: Township of Derry
Phone: 717-566-3237 County: Dauphin
Email: [email protected] Consultant Name: Herbert, Rowland & Grubic, Inc.
Co-Permittees (if applicable): N/A Consultant Name: Alex Greenly 369 East Park Drive Harrisburg, PA 17109 (717)564-1121
Located in central Dauphin County, Pennsylvania; the Township of Derry is an MS4 community currently in its second general permit term; however the MS4 has been owned and operated by the Derry Township Municipal Authority since early 2017 (PAG133637 A-1). The portion of the Township north of Hershey Park Drive (S.R. 0039) remains relatively rural and agricultural; while nearly the entire southern half of the Township has been classified as an Urbanized Area (UA) according to the United States Census Bureau’s 2010 census. The western portion of the Township lies within the Swatara Creek Watershed, the eastern portion lies within the Spring Creek Watershed, and the northern portion lies within the Bow Creek-Swatara Creek Watershed.
1 PADEP, MS4 Requirements Table (Municipal), Last revised 05/09/2017 2 PADEP PRP Instructions (Document #3800-PM-BCW0100k), last revised 03/2017
Chesapeake Bay Pollutant Reduction Plan
DTMA, Derry Township, Dauphin County, PA
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Both Swatara Creek and Spring Creek have been classified by the Pennsylvania Department of Environmental Protection as impaired for various reasons; however, no Total Maximum Daily Load (TMDL), or Waste Load Allocation (WLA) exists for either watershed.
The Authority is also responsible for preparing an Appendix E - Pollutant Reduction Plan for stormwater discharging to the impaired watersheds of Iron Run, Spring Creek, and a UNT to Swatara Creek. Being that all of these surface waters ultimately drain to the Susquehanna River (and Chesapeake Bay), the goals for water quality compliance can be accomplished at the same time, in this CBPRP.
Therefore, the Planning Area used to calculate sediment reduction goals combines the watersheds of the CBPRP with the watersheds requiring an Appendix E pollutant reduction plan. The Authority must also complete an Appendix C PRP for PCBs for the Susquehanna River during the upcoming permit term.
Chesapeake Bay Pollutant Reduction Plan
DTMA, Derry Township, Dauphin County, PA
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Section A: Public Participation A complete copy of this CBPRP was made available for the public to review at the Derry Township Municipal Authority Building from August 1, 2017 to August 31, 2017. The availability of the document was publicized in The Sun Newspaper on July 27, 2017. The published public notice contained a brief description of the plan, the dates and locations at which the plan was available for review by the public, and the length of time provided for the receipt of comments.
A copy of the public notice is included in Appendix A. Public comments were accepted for thirty (30) days following the publication date of the public notice. X number of public comments were received. Copies of all public comments and the responses issued to each comment are included in Appendix A.
A public meeting was held on August 21, 2017 at the Hershey Public Library, 701 Cocoa Avenue to present the information contained in this report to the public. Comments and questions regarding the CBPRP were received during the public presentation. A copy of the meeting minutes for the public meeting at which the CBPRP was presented are included in Appendix A.
Several changes were incorporated into this report as a result of public comments. A record of the incorporated changes is included in Appendix A.
Chesapeake Bay Pollutant Reduction Plan
DTMA, Derry Township, Dauphin County, PA
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Section B: Map DTMA’s CBPRP Overall Map located in Appendix B depicts the Township’s entire Municipal Separate Storm Sewer System (MS4), as required under MCM #3, BMPs 2 and 3 of the PAG-13 Notice of Intent (NOI). The Township of Derry encompasses approximately 17,536 acres of land, 10,540 acres of which is considered urbanized area according to the 2010 US Census. The urbanized area within the Township’s
municipal boundary is to be considered the Planning Area for the purpose of the CBPRP strategy. All watercourses, inlets, pipes, outfalls, observation points, existing BMPs, and proposed BMPs within the Planning Area have been located and appropriately identified on the attached map. A separate Land Use Map has also been included in Appendix B.
Chesapeake Bay Pollutant Reduction Plan
DTMA, Derry Township, Dauphin County, PA
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Section C: Pollutants of Concern The pollutants of concern for Derry Township Municipal Authority, shown in Table 1, were determined by referencing the PADEP MS4 Municipal Requirements Table3, revised June of 2017. This table is included in Appendix C. Table 1. Pollutants of Concern by Watershed
Impaired Watershed Pollutants of Concern
Iron Run Appendix E - Siltation (5)
UNTs to Swatara Creek Appendix E - Siltation (5)
UNT to Spring Creek* N/A - Water/Flow Variability (4c)
Susquehanna River* Appendix C – PCB (5)
Spring Creek Appendix E - Siltation (5)
Chesapeake Bay Appendix D - Nutrients, Siltation (4a) *Provided for informational value only. Impairments not directly addressed in proposed CBPRP. Appendix C- PCB
PRP to be submitted at a later date, per PADEP instruction.
Likely sources of these pollutants in the Township have been identified as follows:
Lack of adequate stream buffer Heavy use of lawn fertilizers Agricultural activities Urban runoff
TSS – Total Suspended Solids
TN – Total Nitrogen
TP – Total Phosphorus
3 PADEP, MS4 Requirements Table (Municipal), Last revised 06/26/2017
Chesapeake Bay Pollutant Reduction Plan
DTMA, Derry Township, Dauphin County, PA
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Section D: Determine Existing Loading for Pollutants of Concern Parcels located within the Planning Area that discharge stormwater associated with a General Permit for Stormwater Associated with Industrial Activity (PAG-03) were parsed from the existing load calculations. A summary of parsed lots removed from the Planning Area is shown in Table 2. Table 2. Parsing
Parsed Properties Parsed Properties
Parcel ID Land Use Area Parsed (Acre)
Hershey Co. Technology Center 24-029-040 Hi Density - Mix 23.0 Hershey Foods East Plant 24-020-013 Hi Density - Mix 20.9 Hershey Foods Recycling Center 24-009-046 Hi Density - Mix 3.3 Hershey Co. Reese Manufacturing Plant 24-029-005 Hi Density - Mix 57.4 Penn State University Hershey Medical Center 24-029-020 Hi Density - Mix 216.5 Total Area Parsed (Acre) 321.1
Existing pollutant load calculations were computed for the Township’s Planning Area using MapShed modeling software. MapShed is a “GIS-based watershed modeling tool that uses hydrology, land cover, soils, topography, weather, pollutant discharges, and other critical environmental data to model sediment and nutrient transport within a watershed.”4 This program calculates the existing pollutant loading in terms of pounds per year and evaluates BMP-based pollutant reductions using the PADEP approved BMP effectiveness values (listed in 3800-PM-BCW0100m).
All GIS data used to create the Derry Township Municipal Authority’s pollutant baseline loading model was sourced from the MapShed Download web site.5 The existing pollutant loads have been calculated for the entire Urbanized Area within the municipal boundary, as this area represents the regulated area that discharges stormwater to the Chesapeake Bay. This area also encompasses the impaired reaches of Spring Creek, Iron Run and UNTs to Swatara Creek listed in PADEP’s MS4 Municipal Requirements table.
Since all impaired watersheds drain to the Swatara Creek-Susquehanna River HUC-12 watershed, and ultimately to the Chesapeake Bay; the required pollutant load reductions for both impaired watersheds will be achieved through the implementation of the DTMA Chesapeake Bay Pollution Reduction Plan, as suggested by PADEP’s Pollutant Aggregation Table.
A summary of baseline pollutant loading for the CBPRP planning area is shown in Table 3.
4. Evans, B., & Corradini, K. (n.d.). MapShed Overview Page. Retrieved August 18, 2015, from
http://www.mapshed.psu.edu/overview.htm 5. Evans, B., & Corradini, K. (2015) MapShed Download Page. Retrieved August 15, 2015, from
The MapShed model results demonstrate that approximately 66% of the Township’s sediment load, or 4,961,783 pounds of sediment per year, is attributed to streambank erosion. Land-based sources and land uses contribute a smaller percentage of the total sediment load, 34% or 2,526,467 pounds per year, but are greater contributors of nutrient loading.
Table 4. Existing Sediment Pollutant Loading for the Township of Derry
Watershed
DTMA Baseline Sediment Load
(lbs/yr)
EX-01 Sediment
Load Reduction
(lbs/yr)
EX-02 Sediment
Load Reduction
(lbs/yr)
EX-03 Sediment
Load Reduction
(lbs/yr)
DTMA Existing
Sediment Load (lbs/yr)
Chesapeake Bay 7,488,250 293,250 400 182,850 7,011,750
Mapshed modeling results for the Authority’s existing pollutant load are included in Appendix D. A modest
assumption that 50% of the existing streams in the Planning Area were adjoined by a forested buffer area, 35 feet in width, was made based on a review of satellite imagery from April 2016.
Existing pollutant load modeling calculations include pollutant load reductions from several existing BMPs (Table 4). The first, identified as EX-01 on the Authority’s MS4 Map included in Appendix B, is a stream stabilization project installed in 2005. The BMP, paralleling Bullfrog Valley Road, consists of the stabilization of approximately 2,550 linear feet of a UNT to Swatara Creek.
Existing BMP EX-02 is a porous asphalt and subsurface infiltration project, located at the Hershey Volunteer Fire Company at 21 W Caracas Ave, Hershey, PA 17033. The BMP treats runoff from a 1 acre, medium density residential drainage area and accounts for a reduction of 400 pounds of sediment per year.
Existing BMP EX-03 is another stream stabilization project completed in 2013. The BMP, paralleling Cocoa Avenue, consists of the stabilization of approximately 1,590 linear feet of a UNT to Spring Creek.
The Authority’s Existing Sediment Load was determined to be 7,011,750 pounds per year. Existing load calculations and existing project information are included in Appendix D.
Chesapeake Bay Pollutant Reduction Plan
DTMA, Derry Township, Dauphin County, PA
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Section E: Select BMPs to Achieve the Minimum Required Reductions in Pollutant Loads Pollutant load reduction requirements (10% TSS, 5% TN, 3% TP) were calculated using the existing base loads determined by the Mapshed software; however, PADEP allows the use of a presumptive approach in which it is assumed that a 10% sediment reduction will also accomplish the required nitrogen and phosphorus reductions6. Therefore, only the required 10% sediment load reduction has been included in Table 5. Table 5: Required Sediment Load Reductions (Appendix E)
Sewershed UA (acres) Impairment Required Sediment Load
Reduction (lbs/yr)
Chesapeake Bay 10,540 Chesapeake Bay Nutrients/Sediment 701,175
The BMP strategy outlined below represents an effective approach to meet the required reduction goals for the Chesapeake Bay and improve the quality of local waterways (Table 6). The proposed BMPs include streambank stabilization and riparian forest buffer restoration at multiple locations in the Authority’s
Planning Area. Since the impaired watersheds of Spring Creek, UNT to Swatara Creek and Iron Creek are located within the overall CBPRP Planning Area, it is recognized that the pollutant load reductions required by the individual Appendix E PRPs listed in the Municipal Requirements table shall be achieved through the successful implementation of the Authority’s CBPRP plan.
6 This assumption is stated in the PADEP PRP Instructions (Document # 3800-PM-BCW0100k)
BMP Type Location (Lat. / Long.)
Map Reference Watershed
TSS Reduction
(lbs/yr) Buffer Restoration – Evangelical Free Church of Hershey
40.254611, -76.647827 BMP-01 UNT to Spring Creek 30,200
Streambank Stabilization
& Buffer Restoration –
Gelder Park / Deer Run 40.245889, -76.715331 BMP-02 UNT to
Swatara Creek 671,425
Total Proposed Reduction: 701,625 lbs/yr
Chesapeake Bay Pollutant Reduction Plan
DTMA, Derry Township, Dauphin County, PA
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BMP Selection Process
The results of the Mapshed model show the majority of the sediment load generated within the Urbanized Area of the Township of Derry stems from streambank erosion. As such, BMPs including streambank stabilization, and riparian buffer restoration were selected to address the instream erosion issues, rather than land-based BMPs, such as bio-retention, rain gardens, or infiltration basins. Final BMP types and locations were determined through discussions with municipal staff, in-field stream views, and a public outreach meeting. BMP location maps are included in Appendix B.
Streambank Stabilization and Buffer Restoration BMPs
Streambank stabilization prevents further erosion and degradation of disturbed or unstable streambanks, ultimately resulting in lower sediment and nutrient loads being released into the stream. The Authority will implement vegetative streambank stabilization to promote plant uptake of nutrient laden runoff in order to reduce the amount of nutrients eventually reaching downstream waterways. Vegetative stabilization relies on the root structures of established plantings to stabilize the streambank and provide scour protection. This method offers a relatively inexpensive means of stabilization and provides a naturalized appearance to the rehabilitated streambank. Reduced grading along the streambank will allow for easier stabilization and reconnection to the floodplain.
The Authority intends to perform a stream buffer restoration project on an impaired UNT to Spring Creek near the Evangelical Free Church of Hershey (BMP-01). The Church has shown interest in teaming with the Authority to conduct a large riparian forest buffer project on an 800 foot section of stream that passes along the southeast corner of the property. The project would include the construction of 35-foot wide forest buffer and adjacent naturalized meadow type buffer. This project would likely be constructed, in-part, by volunteers from the church and the surrounding community.
The second project includes streambank stabilization and riparian forest buffer restoration on a 4,755 foot section of an impaired UNT to Swatara Creek, located near Gelder Park in Hershey (BMP-02). This section of stream is located in a residential development and has become heavily eroded due to lack of adequate buffer, mowed / manicured streambanks, high flow situations, and increased development in the drainage area. The stream was chosen due to the severity of the instream erosion, as well as the Authority’s ability
to obtain property access and easements. In the case that restoration is not feasible for certain portions of the stream, a list of alternate stream restoration project locations is maintained by the Authority’s engineer.
The goal of the projects is to reconnect the streams with the existing floodplain, stabilize areas of erosion and re-establish riparian buffer areas to a minimum width of 35 feet. The riparian buffer restoration will be implemented concurrently with the streambank stabilization in order to maximize the sediment and nutrient load reduction potential of each segment of stream to be enhanced. A summary of reductions achieved on a per project basis are provided in Table 6. Any stream restoration projects will comply with PADEP regulations and shall be in general accordance with PADEP stream restoration guidance.
Chesapeake Bay Pollutant Reduction Plan
DTMA, Derry Township, Dauphin County, PA
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Section F: Identify Funding Mechanism(s) The design and construction of the BMPs proposed herein will be funding through variety of sources including funds collected from stormwater fees, available grants, and public donation of materials and labor. The proposed forest buffer projects will likely be constructed, at least in part, by Authority staff and/or civic and volunteer groups in order to lessen the overall cost of implementing the CBPRP.
Chesapeake Bay Pollutant Reduction Plan
DTMA, Derry Township, Dauphin County, PA
Page 11
Section G: Identify Responsible Parties for Operation & Maintenance (O&M) of BMPs Operation and maintenance requirements for the streambank stabilization and buffer restoration projects shall include:
Ensure disturbed areas are kept free of foot and/or vehicular traffic until full stabilization has occurred.
Regular watering of plantings during first growing season. Planting in the fall may reduce the need for additional watering.
Conduct monthly site visits to ensure plantings are healthy and sufficiently watered, weeds are properly managed, sufficient mulch is in place until site is stabilized and planting have become established.
Conduct monthly site visits to ensure all disturbed earth remains stabilized and erosion or cutting of the streambank has not taken place. Any destabilized earth or active streambank erosion shall be repaired immediately upon discovery.
Conduct annual inspections once streambank is stabilized and plants have become established. Immediately upon notice; repair any rills, gullies, or streambank cutting that may occur. Remove weeds and invasive plant species during each growing season. Naturally growing native
vegetation should be left intact to promoted stabilization of the streambank and surrounding area. Replace mulch as needed. Remove accumulated trash and debris weekly. Remove and replace dead and diseased plantings annually. Keep machinery and vehicles away from stabilized areas.
Operation and maintenance requirements for the existing porous paving project shall include:
Prevent clogging of pavement surface with sediment. Vacuum pavement 2 or 3 times per year. Maintain planted areas adjacent to pavement. Immediately clean any soil deposited on pavement. Do not allow construction staging, soil/mulch storage, etc. on unprotected pavement surface. Use caution when plowing snow from the area. Avoid contact with the pavement surface.
The selected contractor shall be responsible for the operation and maintenance of the streambank restoration and buffer project(s) until all features of the project have been successfully constructed to the specifications and design standards set forth by the Authority Engineer. The contractor shall remain responsible for operation and maintenance of the streambank restoration and buffer project(s) until 70% permanent stabilization has been achieved. Once construction of the project(s) is complete and stabilization has occurred, the Authority shall be responsible for implementing all Operation and Maintenance procedures to ensure the streambank stabilization and buffer improvements remained operationally functional and physically consistent with the original design.
APPENDIX A
Page to be replaced with the following (as applicable):
Copy of the public notice from newspaper
Copies of all public comments and the responses issued to each comment
Meeting minutes for the meeting at which the CBPRP was presented
A record of the incorporated changes as a result of public comment
APPENDIX B
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AMBER DR BOXWOO DDR
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2,000 0 2,000Feet
Mapping derived from data provided by Dauphin County, PA DEP, US Census,and USGS.
[
CBPRP Overall MapDerry Township Municipal Authority
Dauphin County, Pennsylvania
_̂ Existing BMP
_̂ Proposed BMP
Existing BMP Drainage AreaProposed BMP Drainage AreaStorm InletsStorm Outfall PointsStorm ManholesStorm Gravity MainsRoadRailroadImpaired StreamImpaired Water BodyNon-Impaired StreamNon-Impaired Water BodyParsed AreasUrbanized Area (2010)Watershed BoundaryMunicipal Boundary
PM: EGL GIS:HMG369 East Park Drive
Harrisburg, PA 17111717.564.1121 [phone]
717.564.1158 [fax]www.hrg-inc.com
QA: BLS
TEXT
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LIFE LION DR
E 322 ROUTE
W GOVERNOR RDWHERSHEYPARK DR
WOOD RD
BULL FRO GVA LLEY
R D
BULLFROG VALLEY RD
E MAIN ST
CAMP
USDR
UTILITY DR
ROSELAND DRRESEARCH BLVD
~2,550 Ft
Source: Esri, DigitalGlobe, GeoEye, i-cubed, Earthstar Geographics,CNES/Airbus DS, USDA, USGS, AEX, Getmapping, Aerogrid, IGN, IGP,swisstopo, and the GIS User Community
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Mapping derived from data provided by Dauphin County and ESRI.
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CBPRP Map BookExisting EX-01
Derry Township Municipal AuthorityDauphin County, Pennsylvania
_̂ Existing BMPApproximate Length OfStream In ProjectRoadStreamWater BodyMunicipal Boundary
PM: EGL GIS: HMG
369 East Park DriveHarrisburg, PA 17111717.564.1121 [phone]
Source: Esri, DigitalGlobe, GeoEye, i-cubed, Earthstar Geographics,CNES/Airbus DS, USDA, USGS, AEX, Getmapping, Aerogrid, IGN, IGP,swisstopo, and the GIS User Community
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Mapping derived from data provided by Dauphin County and ESRI.
[
CBPRP Map BookExisting EX-02
Derry Township Municipal AuthorityDauphin County, Pennsylvania
Source: Esri, DigitalGlobe, GeoEye, i-cubed, Earthstar Geographics,CNES/Airbus DS, USDA, USGS, AEX, Getmapping, Aerogrid, IGN, IGP,swisstopo, and the GIS User Community
7/20/2017 R005122.0436
0 300Feet
Mapping derived from data provided by Dauphin County and ESRI.
[
CBPRP Map BookExisting EX-03
Derry Township Municipal AuthorityDauphin County, Pennsylvania
_̂ Existing BMPApproximate Length OfStream In ProjectRoadStreamMunicipal Boundary
PM: EGL GIS: HMG
369 East Park DriveHarrisburg, PA 17111717.564.1121 [phone]
Source: Esri, DigitalGlobe, GeoEye, i-cubed, Earthstar Geographics,CNES/Airbus DS, USDA, USGS, AEX, Getmapping, Aerogrid, IGN, IGP,swisstopo, and the GIS User Community
7/19/2017 R005122.0436
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Mapping derived from data provided by Dauphin County and ESRI.
[
CBPRP Map BookProposed BMP-01
Derry Township Municipal AuthorityDauphin County, Pennsylvania
_̂ Proposed BMPApproximate Length OfStream In ProjectProposed BMP DrainageAreaRoadStreamMunicipal Boundary
PM: EGL GIS: HMG
369 East Park DriveHarrisburg, PA 17111717.564.1121 [phone]
Source: Esri, DigitalGlobe, GeoEye, i-cubed, Earthstar Geographics,CNES/Airbus DS, USDA, USGS, AEX, Getmapping, Aerogrid, IGN, IGP,swisstopo, and the GIS User Community
7/20/2017 R005122.0436
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Mapping derived from data provided by Dauphin County and ESRI.
[
CBPRP Map BookProposed BMP-02
Derry Township Municipal AuthorityDauphin County, Pennsylvania
Spring Creek, Swatara Creek-Susquehanna River Chesapeake Bay Nutrients\Sediment, Iron Run, Spring Creek
DAUPHIN BORO PAG133550
Appendix C-PCBCove Creek-Susquehanna River, Laurel Run-Susquehanna River Susquehanna River
Appendix D-Siltation/NutrientsCove Creek-Susquehanna River, Laurel Run-Susquehanna River, Stony Creek Chesapeake Bay Nutrients\Sediment
DERRY TWP PAG133637
Appendix C-PCB, Appendix D-Siltation/NutrientsLaurel Run-Susquehanna River Chesapeake Bay Nutrients\Sediment, Susquehanna River
Appendix D-Siltation/Nutrients, Appendix E-SiltationSpring Creek, Swatara Creek-Susquehanna River Chesapeake Bay Nutrients\Sediment, Iron Run, Spring Creek, Unnamed Tributaries to Swatara Creek
Bow Creek-Swatara Creek, Manada Creek, Swatara Creek-Susquehanna Bow Creek, Chesapeake Bay Nutrients\Sediment, Manada Creek, Raccoon Creek, Unnamed Tributaries to Bow Creek, Unnamed Tributaries to Manada
Bow Creek-Swatara Creek Bow Creek, Raccoon Creek, Unnamed Tributaries to Bow Creek
HARRISBURG CITY PAI133524
Appendix E-Nutrients, Siltation, Suspended SolidsLaurel Run-Susquehanna River, Paxton Creek, Spring Creek Asylum Run, Paxton Creek, Unnamed Tributaries to Spring Creek, Wildwood Lake
Existing and proposed BMP sediment load reductions, with the exception of streambank stabilization, were determined using Mapshed modeling software at the watershed level, not the UA level, due to the watershed based approach required when using Mapshed. The watershed-based sediment load reductions were then applied to the DTMA sediment loading values to determine individual BMP load reductions. The following Mapshed exhibits and associated sediment loadings represent the sediment load reductions achieved at the modeled watershed level. The calculation for credit for each BMP is the difference between the modeled baseline and the BMP output results.