Water Quality Evaluation and Mitigation Alternative Study Town of Dennis, Massachusetts

Transcription

1 Water Quality Evaluation and Mitigation Alternative Study Town of Dennis, Massachusetts David Young, P.E. Vice President Elena Proakis Ellis, P.E. Project Manager Project Update to Board of Selectmen June 30, 2015

2 Comprehensive Wastewater Management Task Force Task Force Members: Diane Chamberlain, Chair Greg Stone Stan Graveline Frank Verny John Harper Suzanne Brock Bob Mezzadri Jay Thrasher Dick O Hearn Town Staff Support: Terry Hayes, Health Department and Liz Sullivan, Assistant Town Administrator CDM Smith: David Young, P.E., Elena Proakis Ellis, P.E. Town of Dennis Water Quality Evaluation and Mitigation Alternative Study

3 Review purpose of study Update Board of Selectmen and public on water quality evaluation findings Show possible sites for wastewater treatment components (facilities and/or effluent recharge basins) Present four scenarios selected by Task Force for further detailed evaluation in next phase Present planning level cost estimates Discuss next steps Meeting Purpose Town of Dennis Water Quality Evaluation and Mitigation Alternative Study

4 The Issue Wastewater is the largest source of nitrogen on the Cape and threatens the town s future Town of Dennis Water Quality Evaluation and Mitigation Alternative Study

5 Beaches, Rivers, Harbors, and Ponds Are Severely Impacted By Nutrients Healthy Nitrogen and Phosphorus Levels

6 Beaches, Rivers, Harbors, and Ponds Are Severely Impacted By Nutrients Unhealthy Nitrogen and Phosphorus Levels Algae in Mill Pond, Yarmouth

7 Why Dennis Needs to Control Nutrients Water Quality Nutrient Impacts Drinking Water Economic Development Beaches, Harbors, Rivers, and Ponds

8 DOING NOTHING IS NOT AN OPTION 2015 Three Bays Economic Study If action had been taken in 2005 to reduce nitrogen by 3% by 2013, the average home price would be $16,662 to $32,962 higher in 2013.

9 MEP Summary: Required Nitrogen Removal by Sub-watershed Includes: Bass River Swan Pond River Herring River

10 Goals for Nitrogen Management Dennis Portion of MEP Watersheds Septic Nitrogen ( N ) Removal Rates from Wastewater to Meet TMDL Under Existing Conditions Swan Pond River -75.5% Bass River -47.4% Herring River -100% Town of Dennis Water Quality Evaluation and Mitigation Alternative Study

11 Controllable Nitrogen Sources Swan Pond River Watershed 2% Wastewater Landfill/Solid Waste 12% 5% Fertilizers Impervious Surfaces 6% 3% Water Body Surface Area 72% "Natural" Surfaces Overall Load Town of Dennis Water Quality Evaluation and Mitigation Alternative Study

12 Scargo Lake Phosphorus Loading Low = 5.4 kg/year High = 8.3 kg/year 22% Wastewater 25% Fertilizer 11% 0% 0% 67% Roof Runoff Road Runoff Birds 0% Surface Precipitation 0% 2% 7% 66% 0%

13 Treatment Site Screening Process

14 Treatment Site Screening Criteria Exclusion Criteria 1. Parcel Size Greater than Three Acres 2. Outside Zone of Contribution 3. Outside Special Flood Hazard Areas 4. Outside of Wetlands 5. Favorable Depth to Groundwater Points Criteria 1. Permeable Soils 2. Favorable Development Status 3. Outside Priority Habitat Areas 4. Outside Municipal Wellhead Protection Zone II 5. Town owned Property

15 Sample Screening Map

16 Map of Final Sites SITE 2 SITE 1 SITE 3

17 Wastewater Infrastructure Can Be Consistent with Community Character

18 Chatham Wastewater Treatment Plant (1.1 million gallon per day average flow with open infiltration basins)

19 Water Reuse Kingston Massachusetts Indian Pond Golf Course 325,000 gpd subsurface effluent recharge site

20 Summary of Wastewater Scenarios Scenario Description Fertilizer/ Sewer Stormwater Aquaculture without PRB Credits Sewer with PRB I/A WWTPs 1 All Innovative/Alternative (I/A) Onsite Systems X X 0 2A All I/A with Aquaculture X X X 0 3A Sewer with PRB and I/A X X X X 1 3B Sewer with PRB and I/A X X X X 2 4A Sewer with PRB X X 1 4B Sewer with PRB X X 2 5A Sewer without PRB and Aquaculture X X X 1 5B Sewer without PRB and Aquaculture X X X 2 6A Sewer with PRB and Aquaculture (includes planning districts) X X X 1 6B Sewer with PRB and Aquaculture (includes planning districts) X X X 2 7A Sewer with PRB and Aquaculture (includes planning districts and several Areas of Concern (AOCs)) X X X 1 7B Sewer with PRB and Aquaculture (includes planning districts and several AOCs) X X X 2 7C Sewer with PRB and Aquaculture (includes planning districts and several AOCs) X X X 3 7D Sewer with Ocean Outfall (includes planning districts and several AOCs) X 1

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24 Scenario Screening Criteria Evaluation Criteria Criteria Weight RELATIVE COSTS 50% Capital Costs 5% O&M Costs 5% Equivalent Annual Cost (EAC) 25% Cost per lb of N Removed 15% TECHNICAL CRITERIA 18% Complexity of Transport 3% Reliability 3% Effluent Recharge Issues 3% Future Recharge Capacity 3% Phosphorus Removal 3% Ability to Handle CECs 3% INSTITUTIONAL CRITERIA 16% Phasing 4% Addresses Other Community Needs 4% Regulatory Considerations 4% Municipal vs. Property Owner 4% ENVIRONMENTAL CRITERIA 16% Effluent Recharge Impacts 4% Water Balance Considerations 4% Sensitive Receptors 4% Construction Impacts 4% TOTAL WITH WEIGHTING 100%

25 Scenario Screening Results Evaluation of Alternatives Evaluation Criteria Criteria Weight 1 2 3A 3B 4A 4B 5A 5B 6A 6B 7A 7B 7C 7D TOTAL WITH WEIGHTING Scenarios 5A and 5B were selected because they rated the highest Scenario 3B was selected to evaluate an option with minimal sewers, decentralized treatment systems, and I/A systems on large lots Scenario 6B was selected to include an option with a decentralized approach and aquaculture that provides infrastructure to economic growth areas

26 Summary of 4 Selected Scenarios 3B 5A 5B 6B Description Aquaculture, I/A and Sewer with PRB Aquaculture and Sewer without PRB Aquaculture and Sewer without PRB Aquaculture and Sewer with PRB (includes planning districts) Fertilizer/Stormwater Credits X X X X Number of Parcels with I/A Systems 395 Acres of Aquaculture Number of Parcels Sewered 4,826 5,234 5,234 5,471 Number of WWTPs Number of Effluent Recharge Sites PRB at Recharge Site X X Average Daily Flow to WWTP #1 (Swan Pond) 367, , , ,000 Average Daily Flow to WWTP #2 (Bass River) 268, , ,000 Annual Pounds Nitrogen Removed 67,179 66,422 66,422 71,184 Cost per Pound Nitrogen Removed $ 280 $ 250 $ 270 $ 280 Capital Cost Ranges: $186M $217M Annual O&M Cost Ranges: $5.22M $6.98M Equivalent Annual Cost Ranges: $17M $20M For Comparison: Dennis appropriated $16M for FY15 Dennis/Yarmouth Regional School budget

27 Cost Recovery Options Property Taxes Betterments Sewer User Fees Municipal Water Infrastructure Investment Fund (similar to Community Preservation Act up to 3% allowed) Meals and Room Taxes (2% increase in Room Tax = $185,000) Local Infrastructure Development Program (Public/Private Partnerships) Mil Charges (fee based on water consumption) Other Beach Parking ($694,427) Beach Stickers ($695,716) Waterway Slip Charges ($486,470)

28 Next Steps 12 Months Finalize effluent recharge modeling and evaluate potential impacts Evaluate collection system types and treatment technologies Gather more information on non traditional technologies (aquaculture, permeable reactive barriers, floating wetlands) Refine life cycle costs for each scenario Develop criteria and ratings system to compare four final wastewater scenarios Select final recommended program Determine appropriate phasing and cost recovery plan

29 Summary Nutrient reduction will be mandated by regulatory agencies (TMDLs issued); action now allows more town control This is a complex planning process that will continue indefinitely, through adaptive management Towns need to determine how best to fund these programs Most properties in town contribute to the problem not just those along a water body or those proposed for a solution Everyone in Dennis will benefit from improved water quality

30 Questions? Sign up to be on the list: the Task Force at: Read or download full Task 1 Report at: Terry Hayes, Dennis Health Department thayes@town.dennis.ma.us Town of Dennis Water Quality Evaluation and Mitigation Alternative Study

31 All Scenario Maps

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