two equations be solved for the two unknowns:

$9\mathrm{.}55$ The following data are given: vertical$-$walled reservoir, surface area $=1,000$ acres; emergency spillway width $=97\mathrm{.}1ft($ideal spillway$)$; $H=$ water surface elevation $($in $ft)$ above the spillway crest; and initial inflow and outflow are both $100cfs.$

$($a$)$ In acre$-$ft and cfs$-$days, determine the values for reservoir storage $S$ corresponding to the following values of $H$:$0,0\mathrm{.}5,1,1\mathrm{.}5,2,3,$ and $4ft.$

$($b$)$ Determine the values of the emergency spillway $Q$ corresponding to the depths named in part $($a$).$

$($c$)$ Carefully plot and label the discharge$-$storage curve $($cfs versus cfs$-$days$)$ and the storage$-$indication curve $($cfs versus cfs$,$ Fig. $9\mathrm{.}24)$ on rectangular coordinate graph paper.

$($d$)$ Determine the outflow rates over the spillway at the ends of successive days corresponding to the following inflow rates $($instantaneous rates at the ends of successive days$)$: $100,400,1200,1500,1100,700,400,300,200,100,100,$ and $100.$ Use a routing table similar to the one used in Example $9\mathrm{.}10$ and continue the routing procedure until the outflow drops below $10cfs.$

$($e$)$ Plot the inflow and outflow hydrographs on a single graph. Where should these curves cross?