$($ii$)$ A trapezoidal channel section of bottom width $3\mathrm{.}5m$ and side slopes $1\mathrm{.}5H$:$1\mathrm{.}0V,$ conveys a flow of $12\mathrm{.}0$ cumees at a depth of flow of $1\mathrm{.}75m.$ For cross regulation works, it is proposed to have a gradual drop in the bed of the channel. Assuming the transition to take place with an energy loss of $14\%$ of the upstream flow depth, and allowable change in water surface level $(y)$ is $30cm,$ determine:

$($a$)$ Whether there will be a rise or drop in the $\frac{D}{S}$ water surface elevation $?$

$($b$)$ Drop of the channel bed level $(z)$ in the $\frac{D}{S}$ section.

$($c$)$ State of flow in the $\frac{D}{S}$ exprision section.

$[7]$