Question $1(90$ Marks$)$

You are tasked with estimating the discharge value of a car park $($paved surface$)$ with the area of $1\mathrm{.}2$ ha $(300m400m).$

$($i$)$ If we assume that full area flow path constitutes only the overland sheet flow, draw and estimate the flow path if the overland slope is $5\%$ from northeast to southwest of the lot where the discharge point is located. $(20$ marks$)$

$($ii$)$ Estimate the time of concentration by Friend's Equation using the nomograph in Figure $9\mathrm{.}4.(20$ marks$)$

$($iii$)$ Assume that the time of concentration after adding the travel time of network flows equals $1$ hour, estimate coefficient of runoff $(C$ in $Q=$CIAK $)$ for $5-$year rainfall event using the chart below, Table $9\mathrm{.}7,$ Table $9\mathrm{.}8,$ and Table $9\mathrm{.}9.(30$ marks$)$