Sediment-source tracing uses the composition of sediment to establish the origin of habitat-impairing sediment. Tracing is especially suited to mountain streams, where bed conditions can change dramatically over time. Samples drawn from the active bed, older flood deposits, high-water marks, and bars of known age allow quantitative estimates of past sediment regimes to be developed. Results may be used in managing aquatic habitat and operating reservoirs or diversion facilities.