Question

The land use of an area and the corresponding runoff coefficients are as follows:

$\begin{array}{cccc}\text{S.no}& \text{Land use}& \text{Area(ha)}& \text{Runoff}\\ & & & \text{Coefficient}\\ 1.& \text{Roads}& 10& 0.70\\ 2.& \text{Lawn}& 20& 0.10\\ 3.& \text{Residential area}& 50& 0.30\\ 4.& \text{Industrial area}& 20& 0.80\end{array}$

What is the equivalent runoff coefficient?

• A. 0.15
• B. 0.36
• C. 0.40
• D. 0.51

Answer 1

The correct option is C 0.40

$K_{eq}=\frac{K_1{A}_1+K_2{A}_2+K_3{A}_3+K_4{A}_4}{A_1+A_2+A_3+A_4}$

$=\frac{0.70\times 10+0.10\times 20+0.30\times 50+0.80\times 20}{10+20+50+20}$
= 0.4