CIV E 632 - COMPUTATIONAL HYDRAULICS AND HYDROLOGY
FALL 2021
HOMEWORK No. 3
A flood wave passes through a point located at the upstream end
of a river reach 500 miles long and generates the following
sinusoidal hydrograph (unit-width analysis):
q(t)= 125 - 75 cos ( π t / 48) (0 ≤ t ≤ 96 hr)
q(t) = 50 (t ≥ 96 hr)
Discharge is given in cfs/ft. The channel bed slope
is So = 1 ft/mi and Manning n = 0.02972.
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Calculate the constant-parameter
Muskingum-Cunge method of flood routing.
Plot the flood hydrograph at the downstream
end of the river reach.
Use a reference discharge qo = 125 cfs/ft (the average
of peak and base flows).
Time interval (Delta t) Δt = 6 hr.
Space
interval (Delta x) Δx = 25 mi.
Total simulation time TST = 30 days.
Report Courant and cell Reynolds numbers,
peak flow, time-to-peak,
and percentage of mass conservation (excluding baseflow).
Recalculate the hydrograph obtained in step 1 four times,
each time doubling the space interval, to 50, 100, 250 and 500 miles.
Plot the results and compare with the results that you obtained in step 2.
Analyze the results using Muskingum-Cunge accuracy criteria.
Verify the applicability of the diffusion wave model to this
particular routing problem.
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