a$)$Write the energy balance between point $1$ on the upstream water surface and point $2$ on the downstream water surface. In this application we need to retain the velocity head terms in the energy balance $($cannot neglect as small, as we can with groundwater flow$).$ However, you can assume that head loss through the gate is small and can be neglected. Combine the energy balance with the continuity equation to give an expression for v$1$ as a function of the water depth upstream and downstream of the gate. For channel width w$,$ write an equation for flowrate, where Q $=$ v$1$ A$1.=$ v$1$ h$1$ w$.$ Hint: use continuity, A$1$v$1=$ A$2$v$2$ to eliminate v$2.$