Perform all flood routing calculations $($Level Pool Routing$)$ of box culvert design: $3$ cells of $2\mathrm{.}4$m x $2\mathrm{.}4$m with Q $=58$m$3/$s $,$ Average slope $=0\mathrm{.}0236$ m$/$m

Use level pool routing to determine the following :

$1.$ Determine the storage volume $($S$)$ for different water levels at the site, and assume that the storage volume $=0$ at the invert level of the culvert $($assume that any storage volume below this invert will not result in any attenuation$).$

$2.$ Use the dimensions of the existing culvert or select a suitable size for the analysis by employing Figure $7\mathrm{.}4($if temporal storage is considered, the required discharge will

decrease$).$

$3.$ Determine the head$/$discharge relationship for inlet$-$controlled conditions in accordance with the relationships reflected in Table $7\mathrm{.}2.$

$4.$ Draw a graph showing the relationship between outflow $($O$)$ and the auxiliary function, N$.$

$5.$ For each time increment $\backslash$Delta t$,$ calculate the change in the value of the auxiliary function, For each time increment $\backslash$Delta N$.$

$6.$ Calculate successive values of N by setting N$2=$ N$1+$ N$\backslash$Delta $.$ Corresponding values of the outflow, O$,$ for known N$-$values, can be read off the graph which represents the relationship between N and the outflow rate, O $($auxiliary graph$).$