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<tr>
 
<tr>
 
<td>Filtration - media</td>
 
<td>Filtration - media</td>
<td>Neglibible, except for access</td>
+
<td>Negligible, except for access</td>
 
<td>5 acre maximum; 0.5-2.0 acre preferred</td>
 
<td>5 acre maximum; 0.5-2.0 acre preferred</td>
 
<td>Media part of design<sup>d</sup></td>
 
<td>Media part of design<sup>d</sup></td>

Revision as of 13:22, 12 March 2013

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 Negligible, except for access 5 acre maximum; 0.5-2.0 acre preferred Media part of designd 2-6 feet0 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