Pacific Southwest Research Station

Kings River Experimental Watershed

SEDIMENT

Sediment loading in streams, particularly on small streams with large storm events, such as those in the KREW study, can be significantly affected by roads and other management activities. Gaining a better understanding of how treatments affect sediment is an important consideration for land managers, and an important component of KREW.

Sediment basins were built on seven of the KREW watersheds (a basin already existed at Teakettle) to quantify sediment coming off of each watershed. These basins are designed to slow down stream flow, which allows sediment to settle out at the bottom of the basin. Once a year, the basins are drained and the remaining sediment is manually removed and weighed to determine the previous year’s sediment load. A portion of the removed sediment is dried and processed in the laboratory to determine the amount of organic versus inorganic matter in the sediment. The specific protocol for this process, as well as dimensions and locations of basins, can be found in the KREW Study Plan (Hunsaker et al. 2004).

Investigations on stream headcuts and upland erosion provide information on the sources and processes that govern erosion. To supplement the data from sediment basins, KREW is collaborating with graduate students to quantify headcuts and their movement on KREW streams, and erosion in the upland from roads and hillslopes. These projects address topics that are important to land management in the Sierra, but not necessarily linked to logging or fuel-reduction activity. However, both projects are in their early stages and have yet to be refined. Also, as they are Master’s-level projects, each is not guaranteed to continue throughout the planned duration of KREW. For specifics about the sediment component, see the KREW Study Plan (Hunsaker et al. 2004).