HR: 16:45h
AN: H32I-04    [PDF]
TI: A Sediment Budget Case Study: Comparing Watershed Scale Erosion Estimates to Modeled and Empirical Sediment Loads
AU: * McDavitt, B
EM: billm@oe-i.com
AF: O'Connor Environmental, Inc., PO Box 794, Healdsburg, CA 95448 United States
AU: O'Connor, M
EM: matto@oe-i.com
AF: O'Connor Environmental, Inc., PO Box 794, Healdsburg, CA 95448 United States
AB: The Pacific Lumber Company Habitat Conservation Plan requires watershed analyses to be conducted on their property. This paper summarizes a portion of that analysis focusing on erosion and sedimentation processes and rates coupled with downstream sediment routing in the Freshwater Creek watershed in northwest California. Watershed scale erosion sources from hillslopes, roads, and channel banks were quantified using field surveys, aerial photo interpretation, and empirical modeling approaches for different elements of the study. Sediment transport rates for bedload were modeled, and sediment transport rates for suspended sediment were estimated based on size distribution of sediment inputs in relation to sizes transported in suspension. Recent short-term, high-quality estimates of suspended sediment yield that a community watershed group collected with technical assistance from the US Forest Service were used to validate the resulting sediment budget. Bedload yield data from an adjacent watershed, Jacoby Creek, provided another check on the sediment budget. The sediment budget techniques and bedload routing models used for this study generated sediment yield estimates that are in good agreement with available data. These results suggest that sediment budget techniques that require moderate levels of fieldwork can be used to provide relatively accurate technical assessments. Ongoing monitoring of sediment sources coupled with sediment routing models and reach scale field data allows for predictions to be made regarding in-channel sediment storage.
UR: http://www.oe-i.com
DE: 1815 Erosion and sedimentation
DE: 1824 Geomorphology (1625)
DE: 1871 Surface water quality
SC: Hydrology [H]
MN: 2003 Fall Meeting