Problem $6\mathrm{.}2$

Examine the flood$-$wave propagation characteristics upstream of town C$,$ sketched in Figure P$6\mathrm{.}2.$ The town bridge at $C$ has a maximum capacity of $12,000cfs.$ An analysis of the $50-$year flood hydrographs from the mountain areas at points A and B are sketched below, with peaks of $15,000$ and $7,500cfs,$ respectively. The two reaches $AC$ and $BC$ are $15mi$ and $2mi$ long, respectively. If both river reaches with floodplains are identical and as described in Problem $6\mathrm{.}1$ with $n=0\mathrm{.}02,$ determine the celerity of the flood wave once it exceeds bankfull discharge. How long does it take the flood wave A to reach the bridge? Would re$-$channelization with levees for both reaches $AC$ and $BC$ have an impact on the bridge?