(Solved): #. A combination flood control channel and flood wall system is proposed for a stream in an urban ...

#. 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, and rectangular with a 100 feet bottom width and a constant channel bottom slope of 0.001 feet perfoct. Under design conditions, the water surface elevation a Section A is 416.00ft. m.s]. with the channel invert elevation being 400.00 m.s.l. AN EXCEL SPREADSHEET SOLUTION IS PREFERRED, BUT NOT REQUIRED. 10 4160mst 400 ms -100- Section A 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 0.2 feet or less between computation points. D) Plot the following profiles from Section Ato the point where uniform flow conditions occur: channel invert elevation critical depth elevation normal depth elevation 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. Freeboard is additional height of the sides of a channel above the