The flow from point $A$ to point $C$ is $14$ cfs$.$ The entrance loss coefficient, $k_e,$ at point $B($leaving the reservoir$)$ is $0\mathrm{.}18.$ The two pipes, which run from

point A to point B and from point B to point C$,$ are circular concrete, $18$ in diameter, with a Manning roughness coefficient, $n,$ of $0\mathrm{.}012.$

What is most nearly the distance, $L,$ of the headwater backup in the pipe between points A and $B?$ Note the following culvert formula, which can be

applied to any culvert:

$H=\frac{v^2}{2g}+k_e(\frac{v^2}{2g})+\frac{v^2{n}^{2}L}{2\mathrm{.}21R^{\frac{4}{3}}}$

A$.3\mathrm{.}0ft$

B$.4\mathrm{.}5ft$

C$.17ft$

D$.34ft$