CALIFORNIA RESERVOIR REPORT

Last Updated: January 31, 2026

California is facing a critical situation with its dams and reservoirs due to abnormal weather patterns. Despite an optimistic start to the water year with December storms filling up reservoirs, a dry January has significantly cut into the early-season gains. The snowpack, crucial for replenishing the state's water supply, is below average for this time of year, raising concerns over water availability and management. This is evident in the data showing decreased storage levels in several reservoirs across the state. For instance, Lake San Antonio is currently holding 270,863 acre-feet, a notable deviation from its average of 132,675.92 acre-feet, likely resulting from the December storms. On the contrary, Donnells Reservoir displays a stark deficit, with current storage levels at -86 acre-feet compared to its average of 36,105.04 acre-feet, reflecting dry conditions impacting inflows.

Major reservoirs like Lake Oroville and Shasta Dam are not receiving enough snowmelt inflow, which is crucial for water storage and supply. Recent observations indicate that Lake Oroville, an essential part of the California water system, does not have updated storage data, pointing to potential issues with water levels. Shasta Dam, another significant reservoir, currently holds over 3.8 million acre-feet of water, surpassing its average of nearly 2.9 million acre-feet, likely due to earlier precipitation but still at risk if dry conditions persist. The situation is compounded by the ongoing discussion over Colorado River water use and the struggle of Western states to manage the scarce resource amidst drought conditions. The state's ability to navigate these abnormal conditions, related to snowpack and river flows, is critical for water security, affecting everything from agriculture to urban consumption. As California moves deeper into winter, the scarcity of snowfall and the potential impact on water resources remain a major concern for water managers and citizens alike.

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.