St. Albans Bay Landscape Modeling
Stakeholder Working Group Meeting 4
Phosphorus Dynamics
Scenario Development
St. Albans Town Hall
November 9, 2005
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.
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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.
DRAFT Annual St. Albans Watershed Phosphorus Mass Balance
mt = metric tons/year
Manure Spread (98 mt)
Crops & Pasture
Forest Soil
Dev Fertilizer (6.5 mt)
Developed Soil
TOTAL INPUTS:
65.8+ mt/year
Agricultural Products
(? mt)
Agricultural Soil
Atm Deposition (0.6 mt)
Households (10.7 mt)
Industrial ??
Milk Produced
(40 mt)
Uptake
Ag Fertilizer (? mt)
Dairy Cows
Feed
(78 mt)
Animal Feed (21 mt)
Bedding (27 mt)
Wastewater
Septic Fields
ANNUAL ACCUMULATION:
21.3+ mt/year
Assumptions & Uncertainties
Wastewater Sludge
(4.5 mt household only)
Industrial ??
TOTAL OUTPUTS:
44.5 mt/year
Phosphorus Transport Pathways
Relative Annual P Loads
for Stevens Brook
Base
Flow
Storm
Runoff
Spring
Melt
???
???
???
???
???
???
Clay
Other
0.5 - 13%
0.5 - 12%
0.1 - 5%
2 - 29%
9 - 63%
2.5 - 36%
Clay
Other
.2 - 3%
.5 - 6%
.1 - 3%
< .03%
<.09%
<.01%
Forest Runoff & Erosion
<.05%
<.22%
<.08%
In-stream erosion
???
???
???
Developed Soil
Stormwater Runoff & Erosion
.8 – 3.2%
3 – 12 %
1 – 4.5%
Wastewater
Wastewater Discharge
13 - 44%
???
???
Dairy Cows
Crops & Pasture
Direct Barnyard Discharge
Geese Eat & Transport to Bay
Ag Surface Runoff
Agricultural Soil
Ag Sub-surface Drainage
Forest Soil
Stream Banks & Bed
Assumptions & Uncertainties
Matching Management Practices with Pathways
SOURCE REDUCTION
PROCESS ALTERATIONS
CAPTURE
Ag Surface Runoff & Erosion
Reduce fertilizer usage.
Reduce manure application.
Reduce P in Feed
Use Exclusion
Nutrient Management Plan
Cover crops
Tillage
Timing of manure application
Tiling fields
Buffers/Filter strip
Wetlands
Ag Sub-surface Drainage
Tillage
Nutrient Management Plan
Un-Tile
Phosphorus boxes
In-stream erosion
Rain Barrels and Rain Gardens
Detention ponds
Reduce impervious cover
Detach roof drains from storm pipes
Armoring stream banks
Stream buffering
Restore geomorphology
Dredging sediments
In-stream detention
Stormwater Runoff & Erosion
Reduce fertilizer usage
Reduce automobile use
Stenciling storm drains
Rain Barrels and Rain Gardens
Reduce impervious cover
Better back roads
Sediment traps
Detention Ponds
Bioretention
Infiltration Trench