$4$

Problem $2-(10$ points$).$ A cross section of a stream in southern Canada is shown in the attached figure. The depths measured at various verticals are indicated together with the point of measurements of velocity in each vertical, at $0\mathrm{.}2$ and $0\mathrm{.}8$ depths or $0\mathrm{.}6$ depths at shallow locations.

a$)(4$ points$).$ Using the mid$-$section method, show and define the computational dimensions of the subarea at measurement vertical $4,$ including its width, on the attached figure.

b$)(3$ points$).$ Compute the discharge, in $f\frac{t^3}{s},$ for the subarea of the previous question $($i$.$e$.$ at measurement vertical $4).$

c$)(3)$ Describe a procedure that clearly explains how you should estimate the total discharge $($in $\frac{m^3}{s})$ in the cross section, using the mean$-$section method.