Dam

The dam's head drop from upstream to downstream is $"H".$ The dam has a kev and it rests on a

permeable layer with an impermeable layer underneath it$.$ Which statement is Incorrect? $(3$ points$)$

a$)$ The key increases resistance to weir sliding.

b$)$ The increases resistance to weir overturning.

c$)$ The flow in the permeable bed decreases as the key depth is increased.

d$)$ The head drop $H$ increases as the key depth is increased.

In the dam $($weir$)$ with its flow net shown above, the head drop from upstream to downstream is $10$ feet.

The datum rests on a sandy layer which has an impermeable layer underneath. The coefficient of

permeability is $0\mathrm{.}25f\frac{t}{m}in.$ The weir is $100-ft$ long $($perpendicular to the page$).$ Calculate the flow across

the weir $($cubic ft per min $).(7$ points$)$