Tutorial $1$: A slightly rough brick$-$lined trapezoidal channel $0\mathrm{.}017)$ carrying a discharge of $Q=25\frac{m^3}{sec}$ is to have a longitudinal slope of $S0=0\mathrm{.}0004.$ Analyze the proportions of$,$ a$)$ An efficient trapezoidal channel section having a side of $1\mathrm{.}5$ horizontal: $1$ vertical, b$)$ the most efficient$-$channel section of trapezoidal shape