SOUTH PACIFIC DIVISION Sacramento District
A debris boom was installed across the Isabella Dam service spillway entrance at Isabella Lake, California, May 27, 2023. This was done to protect downstream areas from debris and to keep lake participants from being caught in the spillway flow. USACE PHOTO
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USACE Lowers Isabella Dam Risk Rating, Lifts Operating Restrictions After Unveiling Dam Improvements The U.S. Army Corps of Engineers (USACE) Sacramento District held a ribbon-cutting ceremony April 4, 2023 at Isabella Dam in Lake Isabella, California, to mark the end of Phase 2 construction on the Isabella Dam Safety Modification Project. 98 I AMERICA’S ENGINEERS
he purpose of the project is to reduce flood risk for the southern Central Valley, including Bakersfield, and to provide water storage for downstream water users. “The amount of technical expertise on display behind me is matched only by the incredible and collaborative relationships between our partners,” said Lt. Gen. Scott A. Spellmon, USACE commanding general, as he stood in front of the new 28-foothigh labyrinth weir at Isabella Dam. “I want to extend a very special thanks to the community who came together to help make today a reality.” Isabella Dam consists of a main and auxiliary dam located just north of Lake Isabella, California. In 2006, a USACE study found the dam vulnerable to three potential failure modes: overtopping, seepage, and seismic damage. The Isabella Dam improvements, begun in late 2017, were designed to address each of these failure modes. Over the next five years, the USACE Sacramento District raised both the main and auxiliary dams by 16 feet, excavated a new emergency spillway, improved the dam’s filtering and drainage systems, and installed the labyrinth weir. These safety improvements were substantially completed in November 2022. Speaker of the U.S. House of Representatives Kevin McCarthy (CA-20); Brig. Gen. Antoinette Gant, commanding general of the USACE South Pacific Division; and Col. Chad Caldwell, commander of the USACE Sacramento District, also spoke at the ceremony. The speakers lauded the partnership between federal, state, and local agencies to move the project forward.
BY JEREMY CROFT
