Q$3.$ A rectangular concrete channel $($n$=0\mathrm{.}015)$; B $=4$ m wide on a slope of $0\mathrm{.}004$ is designed to carry a water discharge of $33\mathrm{.}73$ m$3/$s at best hydraulic section conditions. Estimate the uniform flow depth $"$y$".$ B V$=+$R$2/35!/2($SI units$)$ n V$=1\mathrm{.}49-$R$2/351/2($BG units$)$ n $1$ Also, since Q $=$ AV$,$ Q AR$2/35!/2($SI units$)$ Q AR$2/35!!2($BG units$)$ n $1\mathrm{.}49$ n