harrharr Problem $6\mathrm{.}1$

Consider a $100-$ft wide main channel with a bankfull depth of $5ft.$ The floodplain width is $500ft,$ as sketched in Figure P$6\mathrm{.}1.$ Develop a spreadsheet to calculate the cross$-$section area and wetted perimeter as a function of flow depth every $4^{\text{'}\text{'}}$ until a stage of $10ft.$ Consider Manning $n=0\mathrm{.}02$ in the main channel and a slope $S_0=0\mathrm{.}005.$ Repeat the calculations for two values of Manning $n$ on the floodplain $n=0\mathrm{.}02$ and $n=0\mathrm{.}1.$ Calculate the flow velocity, discharge, and flood$-$wave celerity $c=\frac{Q}{}$A for these two floodplain conditions.