Settling chamber surface area for sand filters and perimeter sand filters.
Link to this table

Sand Filter
Maximum Ponding Depth (feet)
< 4
4 to 10
Impervious ≥ 75% (0.25 Vwq) / Dmax (0.25 Vwq) / Dmax
< 75% (0.25 Vwq) / Dmax 0.066 Vwq
Perimeter Sand Filter Maximum Ponding Depth (feet)
<7.5 8 to 10
Impervious ≥ 75% (0.5 Vwq) / Dmax (0.5 Vwq) / Dmax
< 75% (0.25 Vwq) / Dmax 0.066 Vwq