4- Consider uniform flow through an open channel lined with bricks with a Manning coefficient of n = 0.015. If the Manning coefficient doubles (n = 0.030) as a result of some algae growth on surfaces while the flow cross section remains constant, the flow rate will (a) double, (b) decrease by a factor of √(2), (c) remain unchanged, (d) decrease by half, or (e) decrease by a factor of 21/3 5- A trapezoidal channel with a bottom width of 6 m, free surface width of 12 m, and flow depth of 2.2 m discharges water at a rate of 120 m3/s. If the surfaces of the channel are lined with asphalt (n 5 0.016), determine the elevation drop of the channel per km. Answer: 5.61 m 12 m 2.2 m 6 m

4- Consider uniform flow through an open channel lined with bricks with a Manning coefficient of n = 0.015. If the Manning coefficient doubles (n = 0.030) as a result of some algae growth on surfaces while the flow cross section remains constant, the flow rate will (a) double, (b) decrease by a factor of √(2), (c) remain unchanged, (d) decrease by half, or (e) decrease by a factor of 21/3 5- A trapezoidal channel with a bottom width of 6 m, free surface width of 12 m, and flow depth of 2.2 m discharges water at a rate of 120 m3/s. If the surfaces of the channel are lined with asphalt (n 5 0.016), determine the elevation drop of the channel per km. Answer: 5.61 m 12 m 2.2 m 6 m