UPSC Civil Service Exam Questions - Engineering

Q1:

The following four hydrological features have to be estimated or taken as inputs before one can compute the flood hydrograph at any catchment outlet:
1. Unit hydrograph
2. Rainfall hydrograph
3. Infiltration index
4. Base flow
The correct order in which they have to be employed in the computations is

A 1, 2, 3, 4

B 2, 1, 4, 3

C 2, 3, 1, 4

D 4, 1, 3, 2

ANS:C - 2, 3, 1, 4

Unit hydrograph * excess rainfall = direct runoff hydrograph (DRH).

DRH + Base flow = flood hydrograph.