Problem $3\mathrm{.}51$

The principal flowpath for a $95-$acre watershed is a $3,100-$ft stream with a base width of

$7$ ft $,$ side slopes of $2$:$5$:$1($h$.$v$),$ and a depth of about $1$ ft at bankfull flow. The stream is a

regular section with heary brush on the banks The elevation drop over the length of the

stream is $56$ ft $.$ Estimate the time of concentration. Answer given $=18\mathrm{.}5$ minutes