Question

A catchment area of 90 hectares has a run-off coefficient of 0.4. A storm of duration larger than the time of concentration of the catchment and of intensity 4.5 cm/hr creates a peak discharge rate of

• A. $11.3m^3/s$
• B. $0.45m^3/s$
• C. $450m^3/s$
• D. $4.5m^3/s$

Answer 1

The correct option is D $4.5m^3/s$

$Q_P=\text{AIR}/360$
where
$Q_P\text{is Peak discharge in}{m}^3/s$
$\text{I is intensity in mm/hour}$
$\text{A is Area in ha}$
$\text{R is runoff coefficient}$

$\therefore Q_P=\frac{90\times 45\times 0.4}{360}=4.5m^3/s$