Allied & ICAR Exam Bank • ALLIED_1152NAT • 2 Marks
Section 4: Soil and Water Conservation Engineering
Soil Erosion Mechanics and USLE
Subtopic: Universal Soil Loss Equation
Question Statement:
In a watershed under assessment, the USLE parameters are: rainfall erosivity $R = 400\text{ MJ}\cdot\text{mm/(ha}\cdot\text{h}\cdot\text{yr)}$, soil erodibility $K = 0.03\text{ t}\cdot\text{ha}\cdot\text{h/(ha}\cdot\text{MJ}\cdot\text{mm)}$, topographic factor $LS = 2.5$, cover management factor $C = 0.20$, and conservation practice factor $P = 0.50$. The estimated average annual soil loss $A$ in t/(ha$\cdot$yr) is:
Answer Key:
3.0
Step-by-Step Solution & Explanation
By USLE: $A = R \cdot K \cdot LS \cdot C \cdot P = 400 \times 0.03 \times 2.5 \times 0.20 \times 0.50 = 12 \times 2.5 \times 0.10 = 30 \times 0.10 = 3.0\text{ t/(ha}\cdot\text{yr)}$.