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| * Step 3: Select a design surface ponding depth, d<sub>p</sub>' (m) to begin sizing with:<br> | | * Step 3: Select a design surface ponding depth, d<sub>p</sub>' (m) to begin sizing with:<br> |
| For practices with soft (i.e. landscaped) edges and bowl-shaped ponding areas calculate the mean surface ponding depth: | | For practices with soft (i.e. landscaped) edges and bowl-shaped ponding areas calculate the mean surface ponding depth: |
− | <math>d_{p}'=d_{p, max}\times 1/2</math><br> | + | <math>d_{p}'=d_{p, max}\times 1/2</math> |
| {{Plainlist|1=Where: | | {{Plainlist|1=Where: |
| *d<sub>p, max</sub> = maximum surface ponding depth (m)}}<br> | | *d<sub>p, max</sub> = maximum surface ponding depth (m)}}<br> |
| For practices with hard edges and vertical-walled ponding areas (e.g., stormwater planter, soil cell) use the maximum ponding depth: | | For practices with hard edges and vertical-walled ponding areas (e.g., stormwater planter, soil cell) use the maximum ponding depth: |
| <math>d_{p}'=d_{p, max}</math> | | <math>d_{p}'=d_{p, max}</math> |
| + | ==Determine the required surface area of the practice== |
| + | * Step 4: Calculate the surface (i.e footprint) area of the practice (A<sub>p</sub>) needed to capture runoff produced from the catchment during the design storm event:<br> |
| + | For practices where flow is delivered to the filter media bed: |
| + | <math>A_{p}=i\times D\times A_{i}/((d_{a} + (f_{m, min} \times D)) |
| + | {{Plainlist|1=Where: |
| + | *i = Design storm intensity (mm/h) |
| + | *D = Design storm duration (h) |
| + | *A<sub>i</sub> = Catchment impervious area (m<sup>2</sup>) |
| + | *f<sub>m, min</sub> = minimum infiltration rate of the filter media (mm/h) |
| + | |
| + | |
| | | |
| ==Determine the active storage depth of the practice== | | ==Determine the active storage depth of the practice== |