Problem: The 100-m-long 3.5-m-wide concrete rectangular channel shown in Figure 1 has a Manning's n= 0.012 and a bottom slope of S0 = 0.001. The channel entrance is rounded and smooth (negligible headloss at the entrance), and the reservoir water surface is 2.5 m above the bed of the channel at theentrance. Critical flow occurs at the brink. Assume that friction loss, hf (in m), in the channel can beestimated as 2h f = .0 00019⋅Q , where Q (in m3/s) is the discharge in the channel.
(1) Estimate the value for Q
(2) Classify the water surface profile along the channel
(3) Determine the water depths at 30 m upstream of the brink using one-step method
(4) If a rectangular sharp-crested weir (3.5 m wide and 1.5 m high) is installed at the brink, determinethe value for Q
