A $6-$ft$-$wide $5-$ft$-$high CM box culvert $($with an inlet of thick wall

projecting$)$ is constructed as a road crossing over a stream. It is laid on a slope of $0\mathrm{.}003.$ For an inlet$-$control condition, determine the HW if it carries:

$(2)250$ cfs

$($answers: $(1)5\mathrm{.}36$ ft; $(2)6\mathrm{.}41$ ft

$(3)9\mathrm{.}92$ ft$)$