$(15$ pts$)$ Stormwater planter $-$ given the following information:

$4\mathrm{.}83$ acre drainage area, of that, $2\mathrm{.}45$ ac are impervious

$p=1$

$tf=6$hours

cross section of planter: $6"$ max ponding depth,

$3ft.$ of soil media,

$k=\mathrm{.}5ft./$day$,$

$1ft$ stone drainage layer

How large would a stormwater planter with under$-$drain need to be to provide $100\%$ water quality volume treatment $($ie$.,$ filtering practice$)$:

Answer: Af