Supply-based models of suspended sediment transport in streams

• Published in: Water resources research 1983-06, Vol.19 (3), p.768-778
• Main Authors: VanSickle, John, Beschta, Robert L.
• Format: Article
• Language: English
• ISSN: 0043-1397; 1944-7973
• DOI: 10.1029/WR019i003p00768

Sediment supplies and stream discharge together determine the patterns, over time, of suspended sediment loads in small streams. Most of the uncertainty in empirical streamflow‐sediment relationships can be attributed to changing supplies. Our transport model utilizes a power function of the form C = aQb, where C and Q are sediment concentration and stream discharge, respectively. This expression was augmented with a variable S representing sediment storage in the channel system. The resulting supply‐based model was calibrated to concentration and streamflow time series data from four storm events in a small forested watershed in coastal Oregon. We also calibrated the model to data from a controlled reservoir release in Utah, during which streamflow was held constant for an extended period. In all cases the supply‐based model followed observed concentration time series more accurately than did a transport model based on Q alone. We further enhanced performance of the supply‐based model by distributing sediment supplies S among several compartments which were accessed at different levels of stream discharge. Both the single‐compartment and distributed models demonstrate that a knowledge of sediment supplies can improve predictions of suspended sediment concentrations during storm runoff.