Using the hydrograph below, calculate the direct runoff in acre$-$ft and inches over the $400$ square mile basin. You may assume a constant base flow of $500cfs.$

$\backslash$table$[[\backslash$table$[[$time$],[($days$)]],$discharge $($cfs$)],[1,500],[1\mathrm{.}25,1100],[1\mathrm{.}5,1500],[1\mathrm{.}75,2100],[2,2300],[2\mathrm{.}25,1900],[2\mathrm{.}5,1500],[2\mathrm{.}75,1100],[3,500]]$

$43\mathrm{.}2{10}^{6}cf$