Irrigation Water Conveyance and Application Methods
Subtopic: Design and evaluation of irrigation methods
Question Statement:
Which of the following parameters and metrics are standard engineering indices used to evaluate the hydraulic performance of a field sprinkler irrigation network?
Options:
(A) Christiansen's Uniformity Coefficient ($CU$)
(B) Distribution Uniformity of the lowest quarter ($DU = \frac{\bar{x}_{\text{low quarter}}}{\bar{x}_{\text{all}}} \times 100\%$)
(C) Potential Application Efficiency of Low Quarter ($PELQ$)
(D) Reduction of distribution uniformity caused by high ambient wind drift distortion
Answer Key:
A, B, C, D
Step-by-Step Solution & Explanation
All four indices are standard performance metrics for sprinkler irrigation:
- $CU$ measures average deviation from mean depth.
- $DU$ evaluates uniformity received by the under-irrigated lowest quarter.
- $PELQ$ relates low-quarter depth to total applied depth.
- Wind velocity and direction significantly distort spray patterns, dropping $CU$ and $DU$.