1. St. Albans Bay Landscape Modeling Stakeholder Working Group Meeting 4 Phosphorus Dynamics Scenario Development St. Albans Town Hall November 9, 2005

2. Hydrology Modeling Update Incorporated tile drainage, plant growth & transpiration, and snow melt hydrology Calibrating to data from the 1980s for Stevens Brook Uncertainties associated with calibration process. –Climatic data from radio station. –Colchester climate data does not include precipitation. –No data available for St. Albans from 2003-2004. Only 3 months in 2005. –Groundwater recharge rates are calibrated. –Scaling up infiltration rates, flow rates, etc.

3. DRAFT Annual St. Albans Watershed Phosphorus Mass Balance mt = metric tons/year Assumptions & Uncertainties Agricultural Soil Crops & Pasture Dairy Cows Uptake Animal Feed (21 mt) Bedding (27 mt) Ag Fertilizer (? mt) Milk Produced (40 mt) Feed (78 mt) Manure Spread (98 mt) Agricultural Products (? mt) Developed SoilDev Fertilizer (6.5 mt) Atm Deposition (0.6 mt) Households (10.7 mt) Industrial ?? Wastewater Septic Fields Wastewater Sludge (4.5 mt household only) Industrial ?? TOTAL INPUTS: 65.8+ mt/year TOTAL OUTPUTS: 44.5 mt/year ANNUAL ACCUMULATION: 21.3+ mt/year Forest Soil

4. Phosphorus Transport Pathways Agricultural Soil Crops & Pasture Dairy Cows Developed Soil Wastewater Forest Soil Direct Barnyard Discharge Geese Eat & Transport to Bay Ag Surface Runoff Ag Sub-surface Drainage Forest Runoff & Erosion Stormwater Runoff & Erosion Wastewater Discharge Stream Banks & Bed In-stream erosion Base Flow Storm Runoff Spring Melt ??? 0.5 - 13%0.5 - 12%0.1 - 5% 2 - 29%9 - 63%2.5 - 36%.2 - 3%.5 - 6%.1 - 3% <.03%<.09%<.01% <.05%<.22%<.08% ???.8 – 3.2%3 – 12 %1 – 4.5% 13 - 44%??? Relative Annual P Loads for Stevens Brook Assumptions & Uncertainties Clay Other Clay Other

5. SOURCE REDUCTION PROCESS ALTERATIONSCAPTURE Matching Management Practices with Pathways Ag Surface Runoff & Erosion Ag Sub-surface Drainage Stormwater Runoff & Erosion In-stream erosion Reduce fertilizer usage. Cover cropsBuffers/Filter strip Reduce manure application. TillageWetlands Reduce P in Feed Timing of manure application Use Exclusion Tiling fields Nutrient Management Plan Tillage Un-TilePhosphorus boxes Nutrient Management Plan Rain Barrels and Rain GardensArmoring stream banks In-stream detention Detention ponds Stream buffering Reduce impervious coverRestore geomorphology Detach roof drains from storm pipes Dredging sediments Reduce fertilizer usageRain Barrels and Rain GardensSediment traps Reduce automobile useReduce impervious coverDetention Ponds Stenciling storm drains Better back roadsBioretention Infiltration Trench