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Harry L. Englebright Lake is in the foothills of the Sierra Nevada between Marysville and Grass Valley off California Highway 20. The 260-ft (80 m) Englebright Dam was completed in 1941 for the primary purpose of impounding anticipated hydraulic mining waste. However, gold mining in the Sierra Nevada was halted during World War II and never resumed. Today, the lake serves primarily as a recreational facility.
Englebright Lake is the central subject of the Upper Yuba River Studies Program (UYRSP), a research effort funded by the Calfed Bay-Delta Program, which supports not only drilling and other operating expenses, but also staff salaries. The objective of the UYRSP is to "develop a comprehensive plan to restore ecological processes, habitats, and species within the Yuba River drainage," directed at anadromous fish species, primarily spring-run chinook salmon, steelhead trout, and fall-run chinook salmon.
The principal investigator for CMGP's study of Englebright Lake sediment is Noah Snyder (Santa Cruz, CA), a new USGS postdoctoral researcher who earned his Ph.D. at MIT. Noah is working on this study as part of the Coastal Watershed Restoration Project. The principal objective of his work is to map the reservoir sediment in three dimensions. The three-dimensional sediment-distribution map will be used to calculate sediment transport out of the reservoir under several proposed dam-management scenarios. Principal collaborators on the project are Charlie Alpers and Lorri Flint, both with the USGS' Water Resources Discipline (WRD) in Sacramento, CA. Other collaborators include Chuck Holmes (CMGP, St. Petersburg, FL), Jim Bennett (WRD, Denver, CO), David Topping (WRD, Flagstaff, AZ), and Brian J. Haskell (Limnological Research Center, University of Minnesota, Minneapolis), who contributed his valuable expertise to the drilling effort.
Drilling of Englebright Lake sediment was conducted under contract to DOSECC (Drilling, Observation and Sampling of the Earth's Continental Crust, Inc.), a consortium of universities, national laboratories, and a State (Illinois) geological survey. The contractors used the GLAD500 (Global Lake Drilling 500) system, a diminutive version of the GLAD800 platform, also known as the research vessel Kerry Kelts.
Before the drilling program, bathymetric surveys, geophysical surveys, sediment sampling, and bottom photography were carried out by a CMGP team that included Larry Kooker, Pat Hart, Gerry O'Brien, Tom Reiss, Mike Boyle, Hank Chezar, and Jon Childs (Menlo Park, CA).
The drilling program recovered a total of about 300 m of core from 22 holes at 7 sites, in sediment that ranged in grain size from silt to sand to gravel. Total thickness of postdam sediment in the locations cored ranged from 6 to 31 m. The cores are to be analyzed for sediment composition, geochronology, and mercury and gold contents.
In mid-May, Homa Lee, Brian Edwards, Dave Rubin, Brad Carkin, and volunteer Don Woodrow visited the lake to observe the GLAD500 drilling system in action and to assess its applicability to other CMGP projects.
in this issue:
Salmon & Trout Habitat
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