Irrigation Water Conveyance and Application Methods
Subtopic: Design and evaluation of irrigation methods
Question Statement:
Which of the following statements concerning micro-irrigation and sprinkler irrigation systems is/are CORRECT?
Options:
(A) Christiansen's Uniformity Coefficient ($CU$) equals $100\%$ when all catch can depths are identical
(B) In drip irrigation design, the allowable emitter discharge variation between the first and last emitter along a lateral is typically limited to $10\%$
(C) The emitter manufacturing coefficient of variation ($C_v$) reflects precision of fabrication and values below $0.05$ indicate excellent quality
(D) In trickle irrigation, root zone wetting pattern becomes narrower and deeper in coarse sandy soils compared to fine-textured clay soils
Answer Key:
A, B, C, D
Step-by-Step Solution & Explanation
All statements are technically sound and standard in irrigation engineering:
- $CU = 100 [1 - \frac{\sum |x_i - \bar{x}|}{n \bar{x}}]$; if all $x_i = \bar{x}$, $CU = 100\%$ (Option A is correct).
- Standard micro-irrigation lateral design criterion maintains discharge variation $\Delta q \le 10\%$, corresponding to head variation $\Delta H \le 20\%$ (Option B is correct).
- ASAE EP405 standard classifies $C_v < 0.05$ as 'excellent' (Option C is correct).
- Due to high hydraulic conductivity and low capillary matric suction in coarse sand, gravitational force dominates over matric suction, causing narrow deep wetting bulbs (Option D is correct).