Rectangular open channel with a width of $7\mathrm{.}5m$

carrying the discharge $40\frac{m^3}{s}$ at depth $2\mathrm{.}9m.$ If the

width of the channel becomes $7m$ and there is an

upward step with height $0\mathrm{.}8m$ at the same location.

What is the water surface profile due to these

cross$-$sectional changes? Do not forget to put

numbers on your sketch.

Explain your solution on the E$-$y curves.