CALIFORNIA RESERVOIR REPORT

Last Updated: December 21, 2025

California's dam and reservoir system is experiencing unprecedented storage levels due to a series of intense storms and atmospheric rivers that have lashed the state with significant rainfall. This has led to historically high water levels in many of the state's key reservoirs, surpassing records in some cases. For instance, Lake San Antonio's storage has surged to 270,863 from an average of 132,675.92, and Trinity Lake's storage has jumped to 2,018,780 from an average of 1,524,705.2. This is an unusual situation for a state that has frequently grappled with drought conditions, indicating a potentially major shift in water availability and management concerns.

Analyzing the latest observations, it's clear that abnormal conditions are present in several reservoirs. Lake Havasu, near Parker Dam, is below average by 1.41 ft in gage height, while the Bridgeport reservoir near Bridgeport is above average by 3.08 ft in surface elevation. This indicates variations that could impact water allocations and flood risk management. Reservoirs like San Vicente near Lakeside are also experiencing higher than average storage levels, with a current elevation of 683 ft compared to an average of 670.79 ft. These abnormal conditions are likely related to the combination of heavy precipitation, runoff from a substantial snowpack, and river flows that have been enhanced by the recent storms. These factors could challenge dam operations and water resource management, necessitating close monitoring and potential adjustments to ensure safety and optimal use of the increased water supply.

California has over 1,400 reservoirs and dams, which provide water for agriculture, industry, and households. Some of the major reservoirs in the state include Lake Oroville, Shasta Lake, and San Luis Reservoir. These reservoirs are fed by streams, rivers, and creeks such as the Feather River, Sacramento River, and San Joaquin River. The snowpack in the Sierra Nevada mountains is a crucial source of water for these reservoirs, as it melts during the spring and summer and fills the streams and rivers that flow into the reservoirs. However, drought conditions have been a major concern in recent years, with record low levels in some reservoirs. Seasonal trends show that reservoirs are typically at their lowest levels in the fall and winter, and reach their highest levels in the spring and summer. Overall, California’s reservoirs and dams play a vital role in managing the state’s water resources and ensuring a reliable water supply for its residents.

California has over 1,400 reservoirs and dams, which provide water for agriculture, industry, and households. Some of the major reservoirs in the state include Lake Oroville, Shasta Lake, and San Luis Reservoir. These reservoirs are fed by streams, rivers, and creeks such as the Feather River, Sacramento River, and San Joaquin River. The snowpack in the Sierra Nevada mountains is a crucial source of water for these reservoirs, as it melts during the spring and summer and fills the streams and rivers that flow into the reservoirs. However, drought conditions have been a major concern in recent years, with record low levels in some reservoirs. Seasonal trends show that reservoirs are typically at their lowest levels in the fall and winter, and reach their highest levels in the spring and summer. Overall, California’s reservoirs and dams play a vital role in managing the state’s water resources and ensuring a reliable water supply for its residents.