Accession Number PB2013-100440
Title Environmental Streamflow Assessment for the Santiam River Basin, Oregon.
Publication Date 2012
Media Count 75p
Personal Author J. C. Risley J. R. Wallick K. L. Jones
Abstract The Santiam River is a tributary of the Willamette River in northwestern Oregon and drains an area of 1,810 square miles. The U.S. Army Corps of Engineers (USACE) operates four dams in the basin, which are used primarily for flood control, hydropower production, recreation, and water-quality improvement. The Detroit and Big Cliff Dams were constructed in 1953 on the North Santiam River. The Green Peter and Foster Dams were completed in 1967 on the South Santiam River. The impacts of the structures have included a decrease in the frequency and magnitude of floods and an increase in low flows. For three North Santiam River reaches, the median of annual 1-day maximum streamflows decreased 4250 percent because of regulated streamflow conditions. Likewise, for three reaches in the South Santiam River basin, the median of annual 1-day maximum streamflows decreased 3952 percent because of regulation. In contrast to their effect on high flows, the dams increased low flows. The median of annual 7-day minimum flows in six of the seven study reaches increased under regulated streamflow conditions between 60 and 334 percent. On a seasonal basis, median monthly streamflows de-creased from February to May and increased from September to January in all the reaches. However, the magnitude of these impacts usually decreased farther downstream from dams because of cumulative inflow from unregulated tributaries and groundwater entering the North, South, and mainstem Santiam Rivers below the dams.
Keywords Dams
Environmental impact
Flood control
Ground water
Oregon
Recreation
River basins
Stream flow
Tributaries
Water quality


 
Source Agency US Geological Survey
NTIS Subject Category 68D - Water Pollution & Control
48G - Hydrology & Limnology
50B - Civil Engineering
Corporate Author Geological Survey, Reston, VA.
Document Type Technical report
Title Note N/A
NTIS Issue Number 1303
Contract Number N/A

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