Lake Tahoe Dam Rehabilitation Study kicks off with collection of concrete core samples

Tahoe City, Calif. - The Bureau of Reclamation will begin collecting concrete core samples next month in Lake Tahoe Dam as part of the Lake Tahoe Dam Rehabilitation Study. While the dam is currently safe to operate, the study, funded by the Bipartisan Infrastructure Law, is being conducted to evaluate alternatives for needed repairs.

Restoration repairs are needed to address deterioration in the 115-year-old dam structure, which was constructed prior to the introduction of air-entraining admixtures in concrete that allow space for expansion and contraction of water molecules as the concrete goes through natural freeze-thaw cycles. As temperatures at the dam routinely drop below freezing at night and climb above freezing during the day, the dam experiences freeze-thaw cycles regularly, which are known to cause deterioration of the concrete. Additionally, analysis of the concrete in 2005 indicated signs of deterioration from alkali-aggregate reactions. Gate operations have also been affected as gates have become temporarily immobile or unable to close due to the concrete deterioration.

The concrete coring work is planned for early December and will take about one week to complete. Structure of the concrete core samples will be evaluated to determine next steps.

Part of the Newlands Project, Lake Tahoe Dam was completed in 1913 and is one of Reclamation's first constructed projects under the 1902 Reclamation Act. Lake Tahoe Dam regulates the lake outflow into the Truckee River. The water storage regulated by Lake Tahoe Dam accounts for approximately 72% of the storage in the Truckee River Basin. Flows are determined by a Federal Water Master as required by the Truckee River Operating Agreement. Visit https://www.usbr.gov/mp/lbao/programs/lake-tahoe-dam.html to learn more about Lake Tahoe Dam.