$9\mathrm{.}9$ Recorded flow rates for a net rain of $1\mathrm{.}92$ inches in $12$ hours are shown in the table. If the

base flow is $375cfs$ throughout the storm, determine the $12.$ hr unit hydrograph, and con$-$

vert it to a $6-$hr unit hydrograph. Then apply the $6-$hr unit hydrograph to determine the

total hydrograph $($including $400cfs$ base flow$)$ for a $24-$hr storm having four $6-$hr blocks of

net rain at rates of $0\mathrm{.}7,3\mathrm{.}8,10\mathrm{.}8,$ and $1\mathrm{.}8$ in$.$ per hour.