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Line 14: | Line 14: | ||
<tr> | <tr> | ||
<td>Bioretention</td> | <td>Bioretention</td> | ||
− | <td>7-10%; Minimum 200 ft<sup> | + | <td>7-10%; Minimum 200 ft<sup>2</sup> <sup>b</sup></td> |
<td>5 acre maximum; 0.5-2.0 acre preferred</td> | <td>5 acre maximum; 0.5-2.0 acre preferred</td> | ||
<td>Any soil; use underdrain for C and D soils<sup>d</sup></td> | <td>Any soil; use underdrain for C and D soils<sup>d</sup></td> | ||
Line 45: | Line 45: | ||
<td>Varies based on depth</td> | <td>Varies based on depth</td> | ||
<td>5 to 10 acre maximum</td> | <td>5 to 10 acre maximum</td> | ||
− | <td>Native soils with i>=0.2 inches/hour</td> | + | <td>Native soils with i >= 0.2 inches/hour</td> |
<td>2-12 feet</td> | <td>2-12 feet</td> | ||
<td>3 feet</td> | <td>3 feet</td> | ||
Line 53: | Line 53: | ||
<tr> | <tr> | ||
<td>Infiltration basin</td> | <td>Infiltration basin</td> | ||
− | <td>Varies based on | + | <td>Varies based on depth</td> |
<td>5 to 50 acre maximum</td> | <td>5 to 50 acre maximum</td> | ||
− | <td>Native soils with i>=0.2 inches/hour</td> | + | <td>Native soils with i >= 0.2 inches/hour</td> |
<td>2-12 feet</td> | <td>2-12 feet</td> | ||
<td>3 feet</td> | <td>3 feet</td> |
This table shows guidance on BMP selection based on physical feasibility characteristics of a site.
Link to this table.
BMP group | Surface areaa | Drainage area | Soil infiltration rate | Head | Separation from bedrock | Depth to seasonally high water table | Maximum slopec | Ultra-urban |
---|---|---|---|---|---|---|---|---|
Bioretention | 7-10%; Minimum 200 ft2 b | 5 acre maximum; 0.5-2.0 acre preferred | Any soil; use underdrain for C and D soilsd | 4-6 feet | 3 feet | 3 feet | 20% | Yes |
Filtration - media | Neglibible, except for access | 5 acre maximum; 0.5-2.0 acre preferred | Media part of designd | 2-6 feet | 0 feet if enclosed | 3 feet for vegetated; 0 feet if enclosed | 20% | Yes |
Filtration - vegetative | Varies based on depth | 10 acre maximum | Media part of design | 2-6 feet | 0 feet if enclosed | 3 feet for vegetated; 0 feet if enclosed | 20% | Possible |
Infiltration trench | Varies based on depth | 5 to 10 acre maximum | Native soils with i >= 0.2 inches/hour | 2-12 feet | 3 feet | 3 feet | 15% | Possible |
Infiltration basin | Varies based on depth | 5 to 50 acre maximum | Native soils with i >= 0.2 inches/hour | 2-12 feet | 3 feet | 3 feet | 15% | No |
Stormwater ponds | 1-3% | 25 acre minimumb | A or B soils may require liner | 3-10 feet | 0 feet (shallow soil limits design) | 0 feet (except if hotspot or aquifer) | 25% | No |
Constructed wetlands | 2-4% | 25 acre minimumb | A or B soils may require liner | 3-10 feet | 0 feet | 0 feet (except if hotspot or aquifer) | 25% | No |
aSurface area as a function of contributing surface area, except for ponds and wetlands, where it is a function of entire drainage area
b10 acres may be feasible if groundwater is intercepted and/or if water balance calculations indicate a wet pool can be sustained
cSlope is defined as the slope across the proposed location of the practice
dInfiltration gallery could be designed to provide limited recharge