USDA Forest Service

Pacific Southwest Research Station

Pacific Southwest
Research Station

800 Buchanan Street
Albany, CA 94710-0011
(510) 883-8830
United States Department of Agriculture Forest Service. USDA logo which links to the department's national site. Forest Service logo which links to the agency's national site.

Laboratory experiments on fine particle capture by submerged vegetation in stream environment zones (SEZs): the effects of vegetation density, biofilm development and particle composition

Principal Investigator:
Geoff Schladow, University of California-Davis

Proposal [pdf]

Final Report [pdf]

Please contact Dr. Geoff Schladow with questions regarding the final report.

Project Summary:
Stream Environment Zones (SEZs) by their nature only impact sediment removal at times of increased streamflow and stage, when sediment-laden streamwater is flowing through a cross-section comprised of both bare stream channel and the vegetated overbank area. While sediment transport relationships for the bare stream channel are well understood, the removal of fine sediment (and associated nutrients) by the vegetation is poorly understood.

This study focused on the measurement of fine particle capture efficiencies in a laboratory flume using analogs of the vegetation present in an SEZ. As has been demonstrated in preliminary tests, the laboratory flume offers the ability to vary flow rate, substrate density (stems per square meter), stem width, particle concentration, and presence/absence of biofilms (biological surface coatings) in a repeatable fashion and to measure the changing particle size distribution and particle concentration over time. The size-specific removal efficiencies that can be calculated in this fashion can then be used as the basis of assigning removal efficiencies in any SEZ in the Tahoe Basin based on site-specific flowrate, vegetation type and density, and initial particle concentration. Alternatively, the values could be used as part of a comprehensive stream/SEZ model and provide more detailed estimates of the effectiveness of SEZs in achieving restoration goals.