Question

The ordinate of 2 hour unit hydrograph at one hour time interval starting from time t = 0 are $0,10,35,40,33,20,15,13\text{and}0m^3/s$. The ordinate of 4 hour unit hydrograph at t = 4 hours would be ______$m^3/s$.

• A. 34
• B. 66
• C. 32
• D. 68

Answer 1

The correct option is A 34

$\begin{array}{ccccc}\text{Time}& \text{2-hr UH}& \text{Lag 2-hr UH}& \text{DRH}& \text{4-hr UH}\\ & & & & =\frac{\text{DRH}}{2}\times 1\\ 0& 0& -& 0& \\ 1& 10& -& 10& \\ 2& 35& 0& 35& \\ 3& 40& 10& 50& \\ 4& 33& 35& 68& 68/2=34\\ 5& 20& 40& 60& \\ 6& 15& 33& 48& \\ 7& 13& 20& 33& \\ 8& 0& 15& 15& \end{array}$