A $3-$ft$-$wide rectangular channel $($n $=0\mathrm{.}012)$ is laid on a physical slope of $0\mathrm{.}002.$ Classify the channel bed slope if the channel carries:

$(1)20$ cfs

$(2)60$ cfs

Answers $(1)1\mathrm{.}47$ ft; $(2)2\mathrm{.}51$ ft

$(3)3\mathrm{.}50$ ft