A pilot study to evaluate effects of Blackwood Creek channel restoration work on suspended sediment yield

Abstract

ETR cross-sectional sampling and automatic point sampling were utilized to determine initial short-term effects of a sediment control structure on Blackwood Creek at Lake Tahoe, California. Methodology for short-term analysis of watershed stabilization activities is approached using (1) sediment rating curves, (2) simplistic sediment routing analysis and (3) sediment yields. Sediment rating curves were computed and found to vary considerably: A sediment routing technique was developed to analyze data from the ETR sampling network. Comparison between 1978 and 1979 indicates fourfold reduction in sediment below the structure; a threefold increase in the two mile reach below the structure. Average annual rate of suspended-sediment discharge of Blackwood Creek is about 864 tons or 80 tons per square mile for the period 1975 to 1979. Sediment yield for 1979 was 41 percent of the 1978 yield. A 50 percent decrease in suspended sediment yield per unit of water discharge was noted between 1978 and 1979.