Question

There is a concern that a discharge exceeding 6,000 ft’/s from a detention basin will lead to flooding downstream. The basin has the following storage-elevation relationship: The only outflow from

the basin is via a spillway with the following stage-discharge relationship, with Q in ft³/s and H in feet above the spillway elevation of 1160 ft: Q = 1500H1.5 Note that there is no discharge when the volume is less than 1160 ft. An engineer has been asked to determine the basin's response to a storm with the following inflow hydrograph: A time step size of At = 15 minutes has been selected for the analysis. Is this reasonable?а. b. Route the inflow hydrograph through the basin using the Modified Puls Method with atime step of 15 minutes for a total duration of 10 hours (600 minutes), assuming thebasin has an initial volume at the spillway level when the storm begins (z = 1160 ft andS = 192,750,000 ft³). Plot the inflow and outflow hydrographs. What is the peak discharge from the basin? What is the peak water level in the basin at this time (interpolate to determine). Will the discharge exceed the 6,000 ft/s limit?Assuming the discharge does exceed the limit, what could be done to prevent flooding?с.

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