QUESTION $2$

$(35)$

$2\mathrm{.}1.$ You have been appointed by your local government to design preliminarily a dam

at the outlet of the quaternary catchment having the highest net area in D$12$ of the

Orange drainage system. The design is based on the data provided in the Water

Resources of $1990($WR$90)$ reports as follows:

$-$The live storage $(10{10}^6{m}^3)$ is based on a recurrence interval of $50$ years low flow

sequence with an allowance of $25\%$ for sediment accumulation.

The region applies strictly to catchment areas between $0$ and $1400k{m}^2.$ Consider

medium category $($for sediment accumulation$)$

Use $0\mathrm{.}05$ significance level for sedimentation yield.$|$

Calculate:

a$.$ The gross draft $($in $M\frac{m^3}{a})$ to be met

b$.$ Sediment rate $($t$/$a$)$

c$.$ Trap efficiency $(\%)$

d$.$ Average silting rate $($t$/$a$)$

e$.$ Total dam capacity $(M{m}^3)$

$(57=35)$