Minimum Stream Power for Rivers and Deltas

by Howard H. Chang, (M.ASCE), Prof. and Chmn.; Civ. Engrg. Dept., San Diego State Univ., San Diego, Calif.,
Joseph C. Hill, (M.ASCE), Principal Civil Engineer; Dept. of Sanitation and Flood Control, County of San Diego, San Diego, Calif.,

Serial Information: Journal of the Hydraulics Division, 1977, Vol. 103, Issue 12, Pg. 1375-1389

Document Type: Journal Paper


A numerical model for channel alteration is developed for sand-bed rivers and deltas. The unsteady river flow is computed using the continuity equation and momentum equation of flow with prescribed boundary conditions. Changes in cross-sectional area and delta growth are evaluated based upon the continuity equation for sediment and a sediment transport equation. Subject to certain physical constraints, the part of the river on the delta (delta stream) is assumed to adjust its width freely. To determine the variation in delta stream width, it is assumed to vary in such a way that the total stream power of the river flow is a minimum subject to the physical constraints. The analytical results substantiated with field data indicate that the width-depth ratio of the delta stream tends to increase with a decreasing velocity in an aggrading delta stream, while it tends to decrease with an increasing velocity in a degrading delta stream.

Subject Headings: River flow | Hydro power | Rivers and streams | Numerical models | Unsteady flow | Continuity equations | Sediment transport | High-rise buildings

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