Water flows in a rectangular channel $1m$ wide that has a bed slope of $1$ in $600.$ At a point in

the channel a hydraulic jump occurs the upstream and downstream depths being $0\mathrm{.}3m$ and

$0\mathrm{.}8m$ respectively. Assuming that the downstream depth is the normal depth, determine

Manning's $n$ for the channel $($I$).$

$(0\mathrm{.}013)$