Question $2$

a$)$ A composite channel with a specific cross$-$section is shown in Figure Q$2($a$).$ The

Manning's $n$ for the main channel and flood plain $($left and right overbank$),$

respectively, is $0\mathrm{.}03$ and $0\mathrm{.}015.$ The channel side slope of left and right overbank is

$1V$:$2H$ and $2V$:$1H,$ respectively. The main channel side slope is uniform. The bed slope

is given as $0\mathrm{.}0008.$ Determine the channel's flow rate using the Manning's equivalent

method, $($nedeed urgently$)$