CALIFORNIA RESERVOIR REPORT

Last Updated: December 4, 2025

California's dams and reservoirs have recently observed storage levels that present a mixed picture for water supply across the state. As of the latest observations, some reservoirs, such as Lake San Antonio, are experiencing significantly higher than average storage levels, with current storage at 270,863 acre-feet compared to an average of 132,675.92 acre-feet. Similarly, the New Melones Reservoir has storage levels at almost 2 million acre-feet, surpassing its average by a sizeable margin. This increase aligns with reports of one of the wettest Novembers for Pasadena and the San Gabriel Valley in 60 years, suggesting that atmospheric river storms have contributed to the replenishment of certain water bodies. However, other areas like Donnells, with a current storage of -86 acre-feet compared to an average of 36105.04 acre-feet, indicate below-average storage levels, raising concerns about water availability in those regions.

Notably, large water bodies such as Shasta Dam have seen storage rise to 3.8 million acre-feet, well above the average of 2.9 million, which officials have celebrated as a major turnaround for crucial U.S. water supplies. On the other hand, deviations such as the Cherry Valley Dam's negative storage figure suggest data anomalies or immediate water management challenges. These variations in reservoir conditions could be influenced by factors including recent rainfall patterns, infrastructure conditions rated C- by a report card, and state efforts to expand water supply options, such as California's $2.9 billion water plan. The diversity in reservoir conditions underscores the complexity of water resource management in California, requiring careful consideration of snowpack levels, river flows, and potential impacts of climate change to ensure sustainable water supply and ecosystem health.

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.