| PROJECT LOCATION: | ||||
| DATE: | ||||
| PREPARER: | ||||
| ASSUMED VALUES | ||||
| Value | Description | |||
| A | Impervious Recharge Rate = | 40 | in/yr | |
| B | Recharge Rate = | 18 | in/yr | |
| C | Roof Runoff Concentration = | 0.75 | mg/l | |
| D | Road Runoff Concentration = | 1.50 | mg/l | |
| E | Wastewater Concentration = | 35 | mg/l | |
| F | Lawn Nitrogen Leaching = | 25 | % | |
| G | Average Lawn Size = | 5000 | ft2 | |
| H | Nitrogen Application Rate = | 3 | lbs/1000ft2 | |
| INPUT THE FOLLOWING VALUES IN THE UNITS SHOWN | ||||
| Step | Description | Units | Equation | Result |
| 1 | Title 5 Wastewater Flow (Wastewater Flow determined by 310 CMR 15) |
gpd | ||
| Non-residential Alternative: Measured Water Use | gpd | Must be approved by Planning Board | ||
| Residential Alternative: Mean of Title 5 and Avg. Occupancy | gpd | ((Avg. Occupancy/(2 X # of Bedrooms)) X Title 5 + Title 5)/2 = | ||
| 2 | Total Land Area | 1000 ft2 | ||
| 3 | Roof Area | 1000 ft2 | ||
| 4 | Paved Area | 1000 ft2 | ||
| 5 | Fertilized Lawn Area | 1000 ft2 | ||
| CALCULATE THE FOLLOWING VALUES | ||||
| 6 | Natural Area | 1000 ft2 | Step 2-Step 3-Step 4- Step 5 = | |
| 7 | Determine Wastewater in Liters | liters | Step 1 X 3.785 = | |
| 8 | Determine Nitrogen in Wastewater | mg | Step 7 X Value E = | |
| 9 | Determine Roof runoff | liters | Value A X Step 3 X 6.466 = | |
| 10 | Determine Nitrogen from the Roof runoff | mg | Step 9 X Value C = | |
| 11 | Determine Paved Area runoff | liters | Value A X Step 4 X 6.466 = | |
| 12 | Determine Nitrogen from the Paved Area runoff | mg | Step 11 X Value D = | |
| 13 | Determine Nitrogen from Fertilized Lawn | mg | Step 5 X Value H X (Value F/100) X 1243 = | |
| 14 | Determine Natural Area and Fertilized Lawn Recharge | liters | (Step 6 + Step 5) X Value B X 6.466 = | |
| 15 | Determine Total Nitrogen amount | mg | Step 8 + Step 10 + Step 13 = | |
| 16 | Determine Total Recharge on site | liters | Step 7 + Step 9 + Step 11 + Step 14 = | |
| 17 | Determine Total Nitrogen Concentration | mg/liter | Step 15/Step 16 = | |
Model Bylaw: Wellhead Protection Area - Nitrogen Loading
Cape Cod Commission, 1998
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