Water Resources Investigations Report 02-4202

Hydrology and Chemistry of Floodwaters in the Yolo Bypass, Sacramento River System, California, during 2000

By Laurence E. Schemel, Marisa H. Cox, Stephen W. Hager and Theodore R. Sommer


Discharges to and floodwaters in the Yolo Bypass were sampled during winter and spring, 2000.  The primary purpose of the study was to link changes in water quality in the Yolo Bypass to inflows from the Sacramento River (over Fremont Weir) and from four local streams that discharge to the west side of the floodplain.  Specific conductance, chloride, sulfate, dissolved inorganic nutrients, dissolved organic carbon, particulate carbon and nitrogen, suspended particulate matter (mass), and selected dissolved metals were measured in most of the samples.  When the Sacramento River was spilling over Fremont Weir, the water chemistry in the Yolo Bypass was very similar to that in the river except along the western margin of the floodplain where influences of local stream inflow were evident.  When flow over Fremont Weir stopped, floodwaters drained from the Yolo Bypass, and the local streams were the major discharges as the floodwaters receded eventually to the perennial channel along the eastern margin of the floodplain.  After the initial draining of the floodplain, chemical concentrations at sites along the perennial channel showed strong influences of inflows from Cache Creek and Ridge Cut, which are sources of nutrients and contaminants that are potentially hazardous to wildlife.  Runoff from spring storms increased flow in the perennial channel and flushed accumulated nutrients and organic matter to the tidal river. Releases of freshwater to the perennial channel might be beneficial in maintaining habitat quality for aquatic species during the dry seasons.


References Cited
Appendix A: Filtration and Sample Preparation Methods
Appendix B: Illustrations
Appendix C: Tables

This report and associated figures are available online in Portable Document Format (PDF). If you do not have the Adobe Acrobat PDF Reader, it is available for free download from Adobe Systems Incorporated.

Download the Report (PDF, 1 MB)

Document Accessibility: Adobe Systems Incorporated has information about PDFs and the visually impaired. This information provides tools to help make PDF files accessible. These tools convert Adobe PDF documents into HTML or ASCII text, which then can be read by a number of common screen-reading programs that synthesize text as audible speech. In addition, an accessible version of Acrobat Reader 5.0 for Windows (English only), which contains support for screen readers, is available. These tools and the accessible reader may be obtained free from Adobe at Adobe Access .

Kenneth E. Bencala,
Chief, Flow and Geochemical Interactions Project
U.S. Geological Survey, MS 439
345 Middlefield Road
Menlo Park, CA 94025

U.S. Department of the Interior, U.S. Geological Survey
Persistent URL:
Page Contact Information: Contact USGS
Last modified: Thursday, September 01 2005, 02:22:00 PM
FirstGov button  Take Pride in America button