Correct Answer - Option 1 : 38 m
Explanation:
According to Lacey's theory, following formulae has been given below:
- Hydraulic mean depth, \(R = \frac{5}{2}\frac{{{V^2}}}{f}\)
- Area of the channel section, \(A = \frac{Q}{V}\)
-
Wetted perimeter, \(P = 4.75\sqrt Q \)
- Regime mean velocity, \(V = {\left( {\frac{{Q{f^2}}}{{140}}} \right)^{1/6}}\)
- Bed Slope, \(S = \frac{{{f^{5/3}}}}{{3340{Q^{1/6}}}}\)
Calculation:
\(P = 4.75\sqrt Q =4.75\sqrt 64 = 38 \;m\)