Section 4: Soil and Water Conservation Engineering
Soil Conservation Structures
Subtopic: Graded Bunding
Question Statement:
Graded bunds with a safe longitudinal channel grade (0.1% to 0.3%) are recommended instead of contour bunds in areas where:
Options:
(A) Annual rainfall exceeds 700 to 800 mm and soils are heavy clays with low permeability
(B) Annual rainfall is less than 400 mm
(C) Soils are deep sandy loams with rapid percolation
(D) Slopes are completely flat (0%)
Answer Key:
A
Step-by-Step Solution & Explanation
In high rainfall zones (gt;750\text{ mm}$) and poorly drained black soils (Vertisols), contour bunds cause water stagnation and crop drowning; graded bunds safely lead excess runoff to grassed waterways.