Section 4: Soil and Water Conservation Engineering
Hydrograph Analysis & Unit Hydrograph Theory
Subtopic: Assumptions of unit hydrograph theory
Question Statement:
Which of the following assumptions are fundamental to Sherman's Unit Hydrograph Theory?
Options:
(A) Linear response: ordinates of direct runoff hydrograph are directly proportional to rainfall excess depth
(B) Time invariance: the direct runoff response to a given rainfall excess is identical regardless of when it occurs
(C) Rainfall excess is uniformly distributed throughout the specified storm duration
(D) Catchment area changes dynamically during intense monsoon floods
Answer Key:
A, B, C
Step-by-Step Solution & Explanation
Sherman's unit hydrograph theory relies on:
1. Principle of linear response (superposition and proportionality) (A).
2. Time invariance of basin physical characteristics (B).
3. Spatial and temporal uniformity of rainfall excess over the duration (C).
Catchment boundary and drainage area are strictly constant physical properties (D is false).