Section 4: Soil and Water Conservation Engineering
Hydrology and Runoff
Subtopic: Isohyetal Method
Question Statement:
Among precipitation averaging techniques, the Isohyetal method is generally considered superior to Arithmetic Mean and Thiessen Polygon in mountainous terrain because it:
Options:
(A) Accounts for orographic effects, storm morphology, and elevation contours
(B) Does not require rain gauge records
(C) Is entirely automated with zero hydrological judgement
(D) Assumes linear spatial variation across all barriers
Answer Key:
A
Step-by-Step Solution & Explanation
Isohyets are contours of equal rainfall that can be drawn considering topography, elevation gradients, wind direction, and rain-shadow effects, offering the most realistic spatial interpolation in complex terrain.