The bed of a corrugated channel, with Manning’s coeffcient n =0.019 s/m^1/3 drops 25 m every 1500 m. The channel has a semi-circular cross section with total width of W = 10 m (i.e. radius of the semi-circle is 5 m).
1. Given that the stream has a water depth of h = 2.5 m, find the flow rate in the stream
2. A concrete divider with the same Manning’s coeffcient was installed at the middle of the stream. Given that the total flow rate in the stream stays the same, would the water depth in the stream change as a result of the divider? If so, would it increase or decrease? Would the stream velocity change? If so, would it increase or decrease? You may assume the thickness of the divider to be negligible.
Extracted text: concrete (a) W (b) divider h Figure 5: (a) Original channel cross section. (b) Cross section of channel with divider installed. Figure not to scale.