Solution
= Solution
The upstream flow is <subcritical flow>, with $h_1>h_c$. On this branch $dD/dh<0$, so the depth decreases as the bed rises; the velocity $Q/h$ increases. Since the crest height is below $D^*$, the depth remains above $h_c$ and never becomes critical. Over the falling side of the hump the depth increases again to \b[$h_1$ downstream]. The free surface falls over the hump: $d(h+D)/dD=-\mathrm{Fr}^2/(1-\mathrm{Fr}^2)<0$ on the subcritical branch.