HEC$-$RAS Set #$37-9-6$A rectangular channel with a bottom width of $9$ m$,$ a bottom slope of $0\mathrm{.}0017,$ and Manning's n of $0\mathrm{.}022$ has a discharge of $37$ cms$.$ A sluice gate installed at the downstream end maintains a water depth of $6$ m just upstream of the gate. Compute the critical depth $($m$)$ of the channel. Enter the answer up to two decimal places $($like $3\mathrm{.}21)$ without unit.