CIV E 530 - OPEN-CHANNEL HYDRAULICS
SPRING 2005
HOMEWORK No. 11

  1. You are observing the rise of a river during flood. The width of the river at the observation point, and for some distance upstream is 280 m, and according to the gage reading, the discharge is 650 m3/s. Estimate the discharge at a point 25 km upstream, if the water surface is rising at the rate of 4 mm/hr at your location.

  2. Solve Problem 1 assuming that you have received information by phone that the rate-of-rise at the upstream point of the study reach is 8 mm/hr. Which estimate is better? Why?

  3. A hydraulically wide channel is operating at Froude number F = 0.2. The unit-width discharge is 4 m2/s. What are the two Lagrange celerities?

  4. Route a flood wave with the following characteristics:

    peak flood Qp = 600 m3;
    baseflow Qb= 100 m3/s;
    So = 0.0007;
    Ap = 350 m2;
    Tp= 85 m;
    β = 1.65;
    Δx = 9.8 km;
    Δt = 1 hr.

    For simplicity, estimate routing parameters C and D based on peak discharge.

    The 24-hr flood hydrograph at the upstream cross section, measured at hourly intervals, is:

    130, 150, 180, 220, 250, 300, 360, 450, 520, 600, 550, 490, 370, 330, 310, 280, 230, 170, 150, 130, 120, 110, 105, 100.