Corps to begin geotechnical studies at Isabella Lake

Published March 4, 2013

SACRAMENTO, Calif. – The U.S. Army Corps of Engineers Sacramento District is set to begin geotechnical studies at Isabella Lake in mid-March 2013 as part of the Isabella Lake Dam Safety Modification Project.

Some of the work taking place includes: geological mapping; obtaining rock samples for materials investigation and testing; and determining rippability of onsite materials. Rippability is a measure of a material’s ability to be excavated with conventional excavation equipment.

Results from the studies will be used for preconstruction engineering and design, and help determine whether soil and rock near the lake is suitable for use in proposed safety upgrades identified in the Isabella Lake DSM Project.

The geotechnical studies are scheduled to continue through late 2013.

Study areas include the vicinity of both dams; the current spillway; both highway 155 and 178; and the site of the proposed emergency spillway. Although these areas will remain open for public use during geotechnical work, certain local restrictions may apply. Visitors are encouraged to contact the Corps at 916-557-5100 for the most current local restrictions.

Compliance with all applicable federal, state and local environmental laws and regulations is required for the work proposed. The studies will not involve in-water work. No known sensitive habitats or cultural sites have been identified in the vicinity of the proposed geotechnical work locations. Once the geotechnical studies are complete, all study sites will be restored as nearly as practical to their present conditions.

Completed in 1953, Isabella Dam is located approximately 42 miles northeast of Bakersfield. The reservoir is impounded by two earthen dams on the Kern River and Hot Springs Valley. Today, Isabella Lake and its dams help reduce flood risk for Bakersfield and the surrounding region, and are a primary water source for water users throughout Kern County. The Isabella Dam Safety Modification Project looks to address overtopping, seismic and seepage issues identified with Isabella Lake’s main and auxiliary dams to reduce the likelihood of dam failure.

Members of the public who would like additional information on the Isabella Lake Dam Safety Modification Project are encouraged to visit the U.S. Army Corps of Engineers’ Isabella Lake website:

Carlos Lazo

Release no. 13-009