Getting to Know Your Watershed: Lewis Bay

Transcription

1 Getting to Know Your Watershed: Lewis Bay

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3 Lewis Bay

4 Watershed 101: How Does a Watershed Work? Cape Cod watersheds are the contributing areas to surface water bodies, and groundwater wells. They are defined by the movement of groundwater, and do not follow town boundaries.

5 How long does it take water to move through the watershed? years Each drop of water takes a different path through the watershed Some travel in streams and travel faster Some are caught in ponds and take years

6 Getting to know your watershed: Lewis Bay Watershed 7,414 acres Over 10,000 parcels 2 nd most populous of 46 sensitive watersheds Required nitrogen removal: 80%

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9 1971 to 1999 Developed Land (acres) Percent Change Barnstable 83.1% Yarmouth 56.3%

10 Demographic and Economic Data Census Block Groups Comprised of Census Blocks Average Population: 1,300 residents Source: ESRI s Business Analyst 2009 Estimates

11 Source: ESRI s Business Analyst 2009 Estimates

12 Source: ESRI s Business Analyst 2009 Estimates and Missouri Census Data Center

13 Source: ESRI s Business Analyst 2009 Estimates

14 Source: ESRI s Business Analyst 2009 Estimates

15 Source: ESRI s Business Analyst 2009 Estimates and Missouri Census Data Center

16 Source: 2000 U.S. Census Bureau

17 Source: ESRI s Business Analyst 2009 Estimates

18 Source: ESRI s Business Analyst 2009 Estimates

19 Source: ESRI s Business Analyst 2009 Estimates

20 Source: ESRI s Business Analyst 2009 Estimates

21 Source: ESRI s Business Analyst 2009 Estimates

22 Source: ESRI s Business Analyst 2009 Estimates

23 Source: Cape Cod Commission

24 Source: MassGIS

25 The Problem

26 Our Sole Source Aquifer Replenished by Precipitation Six Separate Lenses Sole Source of Drinking Water Watersheds follow groundwater flow

27 Lewis Bay Watershed and Water Table Contours Average Groundwater flow rate is 1-2 feet per day Groundwater flow times range up to 100 years but average up to10 years to arrive in the embayment

28 Wellhead Protection Areas to Public Water Supply Wells Zone IIs Yarmouth Water Dept COMM Water District Hyannis Water Division Barnstable Fire District

29 Septic Systems and our Watershed The septic system of an average three-bedroom home loads 8.5 pounds of nitrogen into the groundwater each year. Approximately 85% of the over 156,000 homes on Cape Cod presently use individual Title 5 septic systems.

30 Water Quality Assessment Massachusetts Estuary Project Watershed and Subwatersheds

31 Water Quality Water Quality Monitoring Stations Sampled 10 to 4 times through the Summer Coordinated by Town of Barnstable Lewis Bay Research Center Town of Yarmouth Over Ten Years of Data

32 The Problem MEP Characterization: Dissolved Oxygen, Chlorophyll, Macroalgae, Eelgrass, Infaunal Animals

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34 Water Quality Present Conditions Nitrogen Concentration in water

35 Water Quality Buildout Conditions Nitrogen Concentration in water

36 Water Quality Pre-Colonial Modeled Conditions Nitrogen Concentration in water

37 Eel Grass Loss of Eelgrass over Time

38 PPM Relative Nitrogen Thresholds < Total Maximum Daily Load Kg/day Watershed mg/l Drinking Water Planning Marine Water Meets TMDL GW-flow

39 PPM Relative Nitrogen Thresholds 10 5 >Total Maximum Daily Load Kg/day Watershed mg/l Drinking Water Planning Marine Water Over TMDL GW-flow

40 Sources of Nitrogen Wastewater 10% 2% From WWTF Fertilizers Impervious Surfaces 5% 8% Water Body Surface Area * 55% "Natural" Surfaces 20% *Including atmospheric water

41 Other Watershed Features Barnstable Water Pollution Control Facility Flow of Treated Effluent in Groundwater

42 Existing Wastewater Treatment in Lewis Bay Watershed Barnstable Water Pollution Control Facility 1935 Built to Serve Downtown Hyannis 8 Filter Beds 0.32 MGD Filter Beds 0.53 MGD Filter Beds 0.77 MGD filter Beds with 4.2 MGD Capacity at Secondary Treatment - Flow limited to 2.7 MGD Peak 2001 Tertiary Treatment 2007 Facilities Plan Approved at 4.2 MGD Capacity Private Facilities Mayflower Place 25,000 GPD Buck Island Condo 30,000 GPD

43 Facility Siting Site Screening Considerations Preliminary Groundwater Modeling Site Characterization Hydrogeology Loading Capacity Tests Detailed Modeling Mounding Water Resource Impacts Costs

44 Implementation, Adaptive Management and Compliance Chatham years Orleans 20 Years

45 Measuring Implementation Progress Capital Expenditures to Date Amount Sewered Percent Removed from TMDL Watersheds Planned Capital Expenditures Projected Expansion Areas Non-Structural Management Progress

46 TMDL Compliance Monitoring Marine Water Quality Eelgrass Benthic Fauna

47 Lewis Bay Percent of Required Septic Nitrogen Removal by Subwatershed 85% Removal 80% Removal Additional Capacity

48 Existing Sewer Service Areas 6,830 Total Parcels 1,410 Sewered Parcels 20% Sewered

49 Areas of Concern from Barnstable Needs Assessment Title 5 Failures Pathogens Public Water Supply Well Protection

50 Combining Existing Sewer Service Areas and Areas of Concern in Barnstable

51 Regional Solutions Combine All Wastewater Needs MEP Technical Scenario for Regional Approach Includes sewering in Yarmouth portion of Watershed

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55 Density and Facilities Siting are Significant Considerations Length of Road/Lot

56 TOWN LINES WASTERWATER MANAGEMENT APPROACHES

57 WATERSHED BOUNDARIES WASTERWATER MANAGEMENT APPROACHES

58 HIGH DENSITY DEVELOPMENT, ROADS AND INDIVIDUAL HOUSES WASTERWATER MANAGEMENT APPROACHES

59 EXISTING CLUSTER RESIDENTIAL AND SCHOOL WASTERWATER MANAGEMENT APPROACHES

60 EXISTING COMMERCIAL DEVELOPMENT WASTERWATER MANAGEMENT APPROACHES

61 GOLF COURSE WASTERWATER MANAGEMENT APPROACHES

62 ABANDONED CRANBERRY BOGS WASTERWATER MANAGEMENT APPROACHES

63 PLANNED DEVELOPMENT WASTERWATER MANAGEMENT APPROACHES

64 CENTRALIZED TREATMENT WASTERWATER MANAGEMENT APPROACHES

65 CENTRALIZED TREATMENT WASTERWATER MANAGEMENT APPROACHES

66 CENTRALIZED TREATMENT WASTERWATER MANAGEMENT APPROACHES

67 SATTELITE TREATMENT WASTERWATER MANAGEMENT APPROACHES

68 EXISTING CLUSTER TREATMENT WASTERWATER MANAGEMENT APPROACHES

69 PLANNED CLUSTER TREATMENT WASTERWATER MANAGEMENT APPROACHES

70 INDIVIDUAL TREATMENT WASTERWATER MANAGEMENT APPROACHES

71 OPTIMIZING THE PLAN

72 OPTIMIZING THE PLAN Relocating disposal area outside watershed gets major nitrogen credit.

73 Joint use of disposal area saves land and operating costs. Reclaim Area OPTIMIZING THE PLAN

74 OPTIMIZING THE PLAN Regionalizing WWTP s saves operating and capital upgrade costs

75 OPTIMIZING THE PLAN Reuse (natural attenuation) saves land and gets nitrogen removal credit

76 OPTIMIZING THE PLAN Planning disposal area outside watershed saves WWTP upgrade costs and gets N credit

77 OPTIMIZING THE PLAN Joint use of disposal area saves operating costs and land.

78 OPTIMIZING THE PLAN Fertilizer control program produces additional nitrogen reductions

79 OPTIMIZING THE PLAN Use of abandoned cranberry bog attenuates N and lowers operating costs.

80 OPTIMIZING THE PLAN With optimized plan, major areas away need only Title V systems with substantial cost savings.

81 Cost Considerations in Watershed Based Planning Collection and Transport Density Treatment Appropriate Scale Disposal Nitrogen Sensitive Areas, Zone II s

82 Building Footprint With/Without Title 5 Source: Sewers and Smart Growth: Challenges, Opportunities and Strategies, March 2009, Ridley & Associates, Inc.

83 Septic Septic Load Load in in in Watershe, Watershed, Watershed, lb/yr lb/yr lb/yr SEPTIC LOAD LOAD IN WATERSHED, IN LB/YR LB/YR Impact of Growth on N Removal % Growth 30% growth Remove 100% of New Growth new Remove Remove 50 lb/yr 50 lb/yr TMDL TMDL Remove Remove 80 lb/yr 50 lb/yr existing Remain Remain 50 lb/yr 50 lb/yr Remain Remain 50 lb/yr 50 lb/yr 0 0 CURRENT CURRENT CURRENT CURRENT FUTURE FUTURE FUTURE FUTURE

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