Selecting Sediment Transport Equation for Scour Simulation at Bridge Crossing

Chang, Howard H.; Harris, Carroll; Lindsay, Bill; Nakao, Steve S.; Kia, Ray; ,

Selecting Sediment Transport Equation for Scour Simulation at Bridge Crossing

by Howard H. Chang, San Diego State Univ, San Diego, United States,
Carroll Harris, San Diego State Univ, San Diego, United States,
Bill Lindsay, San Diego State Univ, San Diego, United States,
Steve S. Nakao, San Diego State Univ, San Diego, United States,
Ray Kia, San Diego State Univ, San Diego, United States,

Document Type: Proceeding Paper

Part of: Hydraulic Engineering

Abstract:

Gravel transport formulas were tested in order to select a formula for simulating stream channel changes of Stony Creek in northern California. At a stream reach undergoing scour, the amount of scour will be over predicted by a sediment formula giving too high values of transport, and vice versa. If a formula overpredicts the transport rate, it will indicate a refill in gravel pits greater than the measured value. On the other hand, a formula under-predicting the transport rate will show less refill than the measured amount. For the Stony Creek study, the following formulas were used separately for test and calibrations: Meyer-Peter Muller (MPM) formula, Yang formula for gravel, Parker formula, and Engelund-Hansen Formula. It should be noted that the Eugelund-Hansen formula was not developed for gravel bed streams. The deliveries obtained from Yang's formula and Parker's formula are more or less similar. The Engelund-Hansen formula overpredicts the transport rate while the Meyer-Peter Muller formula underpredicts the transport rate. Erosional changes at the Highway 32 bridges crossing and depositional changes in the gravel pits are most significant. Simulated changes at this bridge crossing compare favorably with the measurement for all the sediment formulas used, but certain formulas are apparently better than others on the basis of the comparison.

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