A combination flood control channel and flood wall system is proposed for a stream in an urban area. A typical cross$-$section is shown on Section A$.$ The design discharge is $35,000$ c$.$f$.$s$.$ The channel is concrete$-$lined $($n$=0\mathrm{.}013),$ and rectangular with a $100$ feet bottom width and a constant channel bottom slope of $0\mathrm{.}001$ feet per foot. Under design conditions, the water surface elevation at Section A is $416\mathrm{.}00$ ft$.$ m$.$s$.$l$.$ with the channel invert elevation being $400\mathrm{.}00$ m$.$s$.$l$.\backslash$#$3.$ A combination flood control channel and flood wall system is proposed for a stream in an urban area. A typical cross$-$section is shown on Section A$.$ The design discharge is $35,000$ c$.$f$.$s$.$ The channel is concrete$-$lined $(\backslash ($ n$=0\mathrm{.}013\backslash )),$ and rectangular with a $100$ feet bottom width and a constant channel bottom slope of $0\mathrm{.}001$ feet per foot. Under design conditions, the water surface elevation at Section A is $416\mathrm{.}00$ ft $.$ m$.$s$.$l$.$ with the channel invert elevation being $400\mathrm{.}00$ m $.$s$.$l$.$

A$)$ Is the design flow condition at this point sub$-$ or super$-$critical?

B$)$ Calculate normal depth for the design flow. What is the correct label for the shape of design profile in this reach?

C$)$ Using the direct step backwater procedure, compute the design water surface profile from Section A to the Upstream location where approximate uniform flow occurs $($it occurs more than one mile upstream from A$).$ Use depth change increments of $0\mathrm{.}2$ feet or less between computation points.

D$)$ On graph paper, plot the following profiles from Section $\backslash ($ A $\backslash )$ to the point where uniform flow conditions occur:

$(1)$ channel invert elevation

$(2)$ critical depth elevation

$(3)$ normal depth elevation

$(4)$ water surface profile elevation for the design flow

E$)$ Floodwalls must include an adequate freeboard against overtopping, with at least $3$ feet necessary for the design flood. Plot the top of floodwall profile.

F$)$ Label the shape of the design water surface profile.