Do problem $9\mathrm{.}13$ in the text on page $376.$ Your solution should include the data points for the $8$ hour UH and a plot of both the $\backslash (4-\backslash$mathrm$\{$hr$\}\backslash )$ and $\backslash (8-\backslash$mathrm$\{$hr$\}\backslash$mathrm$\{$UH$\}\backslash )$ developed. In addition to the developing the hydrograph, find the area of the basin $($in $\backslash (\backslash$mathrm$\{$mi$\}^\{2\}\backslash )$ and Ac $)$ by integrating the $8-$ hr unit hydrograph. The plot must be computer generated and the data points clearly shown to get full credit.

$9\mathrm{.}13$ The ordinates of a $4-$hour unit hydrograph for a $\backslash (42-\backslash$mathrm$\{$mi$\}^\{2\}\backslash )$ basin are given in the following table. Find the $8-$hour unit hydrograph by the lagging method.