A rectangular channel has a flow depth of $6\mathrm{.}0ft$ with a flow rate of $200cfs.$ The channel width is also $6\mathrm{.}0$ feet. The channel slope is less than $10\%.$

Calculate the following values.

Specific energy

Alternate depth. $($Indicate all the roots and explain why only one of the three roots is the solution to this problem.$)$

Critical depth

Critical $($minimum$)$ energy.