Unit stream power and sediment transport

UNlT STREAM POWER FOR SEDIMENT TRANSPORT IRI NATIJRAL RIVERS The relationship between rate of sediment transport and rate of potential energy expend-iture has been studied in detail. Unit stream power, defined as the time rate of potential energy expenditure per unit weight of water, is shown to be the dominant factor in the determination of total sediment concentration. Basic concepts in fluid mechanics and boundary layer theory are used to establish the flow condition at incipient motion. Two equations that provide simple and direct criteria for incipient motion are found. These equations are verified by 153 sets of data independently collected by eight investigators. A dimensionless unit stream power equation is found for the prediction of total sediment concentration for both laboratory flumes and natural rivers. 'This equation not only provides a good estimation of the total sediment concentration in an alluvial channel but also correctly reflects the effects of the variations of particle size, water depth, and water temperature on total sediment concentration. Data collected from six natural rivers and more than one thousand sets of laboratory data are used in supporting this equation. Data collected from 17 regular gagin