This question was previously asked in

MPPSC AE CE 2016 Official Paper - II

Option 1 : 0.467 m/s

CT 3: Building Materials

2962

10 Questions
20 Marks
12 Mins

**Concept:**

According to Lacey, the design formulas to build canal is as follows:

(1) Silt factor ⇒ \(\rm{f = 1.76\sqrt {{d_{mm}}}}\)

(2) Velocity of flow ⇒\(V = {\left[ {\frac{{Q{f^2}}}{{140}}} \right]^{\frac{1}{6}}}\)

(3) Hydraulic mean depth ⇒\(R = \frac{{5{V^2}}}{{2f}}\)

(4) Wetted perimeter ⇒ \(P = 4.75\sqrt Q\)

(5) Bed slope ⇒ \(S = \frac{{{f^{\frac{5}{3}}}}}{{3340 \times {Q^{\frac{1}{6}}}}}\)

**Calculation:**

Given,

Q = 2.01 m^{3}/s, f = 0.85

∵ We know that, \(V = {\left[ {\frac{{Q{f^2}}}{{140}}} \right]^{\frac{1}{6}}}\)

\(V = {\left[ {\frac{{2.01 \times {{0.85}^2}}}{{140}}} \right]^{1/6}} = 0.467\ m/s\)