Question $(4)$:

A rectangular channel carries a flow with upstream velocity of $2\frac{m}{s}$ with flow depth of $3m,$ Find:

a$)$ What is the change in depth by a rise of $0\mathrm{.}3m?$

b$)$ What is the change in depth by a drop of $0\mathrm{.}2m?$

c$)$ What is the maximum size of upward step that could exist before upstream depth changes?