South Shore Nonpoint Source Management Plan
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South Shore Nonpoint Source Management Plan The Towns of: Cohasset, Duxbury, Hanover, Hingham, Marshfield, Norwell, Rockland, Scituate, Weymouth This project was funded by the U.S. Environmental Protection Agency through the Massachusetts Department of Environmental Protection under the Clean Water Act, Section 604(b), Grant #95-03. July 1998 WQ/98-01 Credits and Acknowledgements This report was prepared by the staff of the Metropolitan Area Planning Council under the supervision of the Executive Director. The Metropolitan Area Planning Council is the officially designated regional planning agency for 101 cities and towns in the Boston metropolitan area. The Council offers technical assistance to its member communities in the areas of land use, housing, environmental quality, energy, transportation, and economic development. 1998 – 1999 MAPC Officers Grace S. Shepard, President Richard C. Walker, III, Vice President Donna M. Jacobs, Secretary Richard A. Easler, Treasurer David C. Soule, Executive Director Credits Project Manager: Mary Ellen Schloss Principal Author: Mary Ellen Schloss GIS/Cartography: Paul Spina Assistant Planner: Susan Phinney Planning Interns: Caroline Ganley, Scott G. Robson Graphics: Scott G. Robson Technical Review: Martin Pillsbury Technical Assistance: Bill Clark, MassBays Program South Shore Water Resources Advisory Committee (“Project Committee”) Cohasset Conservation Commission John Bryant Water Commissioner, Water John McNabb Resources Protection Committee Duxbury Town Planner Tom Broadrick Hanover Conservation Commission Joan Donoian Hingham Conservation Agent Pine DuBois Norwell Board of Health Peter Dillon Water Commissioner Steve Ivas Scituate Conservation Commission Charles Sparrell Weymouth Department of Public Works Andrew Fontaine, Bob Leishman Cultural Council Elizabeth DeAngelis Special Thanks To Bill Clark of the MassBays Program for technical advice and support, to the staff and members of the Planning Boards, Departments of Public Works, Conservation Commissions, and Boards of Health who provided critical data and information for this plan, and to George Zoto, EOEA South Coastal Basins Team Leader, for his insightful comments. ii iii TABLE OF CONTENTS Credits and Acknowledgements____________________________________________ ii Executive Summary _____________________________________________________ 1 ES-1 Project Background_________________________________________________ ES-1 ES-2 Report Organization & Content_______________________________________ ES-2 ES-3 Findings & Recommendations ________________________________________ ES-6 ES-3.1 Data Needs ____________________________________________________________ ES-6 ES 3.2 Wastewater ____________________________________________________________ ES-7 ES-3.3 Stormwater Runoff _____________________________________________________ ES-10 ES-3.4 Hazardous Waste and Industrial Sites_______________________________________ ES-13 ES 3.5 Other Pollution Concerns ________________________________________________ ES-16 ES-3.6 Planning for Growth ____________________________________________________ ES-18 ES-3.7 Inter-Community Coordination ____________________________________________ ES-20 Chapter 1: Regional Overview of Land Use and Water Resources _______________ 1 1.1 Watersheds in the Project Study Area _____________________________________ 1 1.2 Regional Land Use Assessment ___________________________________________ 2 1.2.1 Population and Employment _________________________________________________ 2 1.2.2 Land Use ________________________________________________________________ 9 1.3 Drinking Water Supplies _______________________________________________ 13 1.4 Shellfish Beds _________________________________________________________ 17 1.4.1 South Coastal Subbasins ___________________________________________________ 18 1.4.2 Weymouth & Weir Subbasins _______________________________________________ 22 1.5 Areas of Critical Environmental Concern (ACECs) _________________________ 23 Chapter 2: Water Quality Data ___________________________________________ 25 2.1 305(b) Water Quality Assessment ________________________________________ 25 2.2 MAPC Water Quality Database__________________________________________ 26 2.2.1 Fecal Coliform___________________________________________________________ 32 2.2.2 Nitrate-Nitrogen _________________________________________________________ 33 2.3 Water Quality Data by Subbasin_________________________________________ 34 2.3.1 South Coastal Basins ______________________________________________________ 39 iv 2.3.2 Weymouth & Weir Subbasins _______________________________________________ 52 Chapter 3: Potential Pollution Sources ____________________________________ 68 3.1 Potential Pollution Sources Database _____________________________________ 68 3.2 Potential Pollution Sources by Subbasin ____________________________________ 68 3.2.1 South Coastal Subbasins ___________________________________________________ 76 3.2.2 Weymouth & Weir Subbasins _______________________________________________ 89 Chapter 4: Subbasin Assessments and Stormwater Modeling__________________ 99 4.1 Description of Subbasins________________________________________________ 99 4.1.1 Town Brook Subbasin _____________________________________________________ 99 4.1.2 Aaron River Reservoir Subbasin ____________________________________________ 107 4.1.3 Bluefish River Subbasin __________________________________________________ 114 4.2 Summary of the P8 Model: Uses and Limitations __________________________ 121 4.3 P8 Model Application _________________________________________________ 126 4.4 Subbasin Assessment Results ___________________________________________ 131 Chapter 5: Assessment of Local Regulations and Practices ___________________ 140 5.1 Assessment of Local Regulations ________________________________________ 140 5.2 Wastewater Infrastructure_____________________________________________ 150 5.3 Stormwater Infrastructure and Roadway Maintenance _____________________ 153 5.4 Other Local Practices _________________________________________________ 159 5.4.1 Household Hazardous Waste and Waste Oil Collection __________________________ 159 5.4.2 Boat Pumpout Programs __________________________________________________ 162 Chapter 6: Recommended Nonpoint Source Management Strategies ___________ 165 6.1 On-site Wastewater Disposal ___________________________________________ 165 6.2 Stormwater Infrastructure and Maintenance _____________________________ 168 6.3 Local Stormwater Regulation __________________________________________ 174 6.3.1 Local Stormwater Management: Goals, Issues, and Resources ____________________ 174 6.3.2 DEP Stormwater Management Standards _____________________________________ 175 6.3.3 Model Stormwater Regulations _____________________________________________ 177 6.4 Funding Sources for Nonpoint Source Management Projects__________________ 185 v 6.5 Site Planning through Zoning, Site Planning and Subdivision Regulations _____ 187 6.6 Erosion and Sediment Control__________________________________________ 188 6.7 Wetlands Protection __________________________________________________ 190 6.8 Other Regulatory Measures ____________________________________________ 191 References LIST OF TABLES Table 1-1: Project Subbasins in the Study Area _____________________________________________ 5 Table 1-2: Historic Population Trends in the Study Area, 1940 - 1990 ___________________________ 7 Table 1-3: Population and Employment Density in the Nine Project Communities, 1990(a)___________ 8 Table 1-4: MAPC Population Projections for the Project Communities, 1990 - 2020 _______________ 9 Table 1-5: 1991 MacConnell Land Use by Project Subbasin__________________________________ 10 Table 1-6: Municipal Drinking Water Supplies by Project Subbasin ___________________________ 14 Table 1-7: Non-Municipal Water Withdrawals Over 100,000 GPD_____________________________ 16 Table 2-1: DEP Water Quality Ratings For South Shore Rivers And Harbors (South Coastal) ______ 27 Table 2-2: DEP Water Quality Ratings For South Shore Rivers And Harbors (Weymouth & Weir) __ 28 Table 2-3: Fecal Coliform Standards by Designated Use_____________________________________ 33 Table 2-4: MAPC Database: Water Quality Monitoring Stations by Subbasin____________________ 36 Table 2-5: Water Quality Data in the North River Subbasin _________________________________ 41 Table 2-6: Water Quality Data in the South River Subbasin __________________________________ 46 Table 2-7: Water Quality Data in the Green Harbor River Subbasin ___________________________ 51 Table 2-8: Water Quality Data in the Back River Subbasin___________________________________ 53 Table 2-9: Water Quality Data in the Fore River Subbasin ___________________________________ 63 Table 2-10: Water Quality Data in the Hingham Harbor Subbasin ____________________________ 64 Table 2-11: Water Quality Data in the Weir River Subbasin __________________________________ 66 Table 3-1: Data and Map Sources, MAPC Potential Pollution Sources Database ________________ 70 Table 3-2: Summary of Potential Pollution Sources by Subbasin _____________________________ 71 Table 4-1: Town Brook Subbasin: Land Use & P8 Model Assumptions________________________ 103 Table 4-2: Town Brook Subbasin: Land Use & Impervious Fraction Change ___________________ 106 Table 4-3: Aaron River Reservoir Subbasin: Land Use & P8 Model Assumptions _______________ 108 Table 4-4: Aaron River Reservoir Subbasin: Land Use & Impervious Fraction Change___________