$5\mathrm{.}2\mathrm{.}8$ A trapezoidal channel has a bottom width of $10$ ft and side

slopes of $2$:$1(h$:$v).$ Manning's roughness factor is $0\mathrm{.}018.$ For a

uniform flow depth of $2\mathrm{.}9$ ft $,$ what is the normal slope $($correspond$-$

ing to uniform flow depth$)$ and the critical slope of the channel for a

discharge of $200$ cfs $?$