Question Bank • QB_IDE_ADV_062
MSQ • 2 Marks
Section 5: Irrigation and Drainage Engineering
Irrigation Water Conveyance and Application Methods
Subtopic: Design of irrigation channels and underground pipelines
Question Statement:
Which of the following equations represent Lacey's canonical regime equations for stable alluvial irrigation canals in true regime?
Options:
-
(A) Silt factor: $f = 1.76 \sqrt{d_{mm}}$, where $d_{mm}$ is mean sediment diameter in millimeters
-
(B) Regime flow velocity: $V = \left( \frac{Q f^2}{140} \right)^{1/6}$
-
(C) Wetted perimeter: $P = 4.75 \sqrt{Q}$
-
(D) Regime longitudinal bed slope: $S = \frac{f^{5/3}}{3340 Q^{1/6}}$
Step-by-Step Solution & Explanation
All four relationships are Lacey's exact fundamental regime equations:
- A: $f = 1.76 \sqrt{d_{mm}}$ defines the silt factor.
- B: $V = [Q f^2 / 140]^{1/6}$ relates velocity, discharge, and silt factor.
- C: $P = 4.75 \sqrt{Q}$ determines the semi-elliptical wetted perimeter.
- D: $S = \frac{f^{5/3}}{3340 Q^{1/6}}$ defines the unique regime bed slope.
Practice In Authentic CBT Exam Interface
Test your skills under authentic timed conditions with live scoring and AIR percentile ranking.
Launch CBT Mock Test