IDAHO RESERVOIR REPORT

Last Updated: December 25, 2025

Idaho's network of dams and reservoirs plays a crucial role in the state's water management, with recent observations indicating varying conditions across these water bodies. While some reservoirs, such as Priest Lake and Milner Lake, are reported below their average gage heights at 1 foot and 9 feet respectively, others like Coeur d'Alene Lake are above the norm, at 28 feet. Henrys Lake and Mackay Reservoir are close to their average levels, indicating a balance in water inflow and outflow. However, significant deviations are noted in the Salmon River Canal Co. Reservoir, currently at 10 feet, well below its average of 23.78 feet, and Mud Lake, sitting at 2 feet against its average of 3.66 feet. The larger reservoirs, such as Little Wood Reservoir, are also experiencing lower than usual storage levels, with a current measurement of 13,380 acre-feet compared to the average of 17,024 acre-feet. Adjustments in water storage at Lucky Peak Lake and Payette Lake are also evident.

The abnormal conditions in some of Idaho's dams and reservoirs could be attributed to factors such as fluctuating snowpack levels and river flows, which are influenced by both seasonal variations and long-term climate trends. For instance, reservoirs with lower than average levels may be experiencing reduced snowmelt or precipitation, while those above average might benefit from recent weather patterns yielding increased runoff. Moreover, effective wildfire resilience measures, such as those being implemented in Idaho parks as reported by the Missoula Current, can indirectly affect water levels by preserving the surrounding watershed and thus influencing the inflow to reservoirs. The observed water level disparities necessitate ongoing monitoring and potentially adaptive water management strategies to ensure these critical resources are maintained for ecological stability, recreational use, and community safety, particularly in regions recognized by WorldAtlas for their small community appeal in the Rockies.

Idaho has numerous reservoirs and dams that provide irrigation, hydropower, and recreational opportunities. Major reservoirs include Lucky Peak, Anderson Ranch, and American Falls. These reservoirs are fed by streams and rivers such as the Boise River, Snake River, and Portneuf River. The hydrology of the area is heavily influenced by snowfall in the surrounding mountains, particularly the Sawtooth and Rocky Mountains. Snowpack levels are closely monitored as they impact streamflow and reservoir levels. In recent years, drought conditions have led to lower snowpack levels and decreased reservoir levels. Record low levels have been seen in several reservoirs during drought years. Seasonal trends show higher reservoir levels during the spring and early summer due to snowmelt, with levels decreasing through the fall and winter. Overall, reservoirs and dams play a significant role in Idaho's water management and the state's economy.

Idaho has numerous reservoirs and dams that provide irrigation, hydropower, and recreational opportunities. Major reservoirs include Lucky Peak, Anderson Ranch, and American Falls. These reservoirs are fed by streams and rivers such as the Boise River, Snake River, and Portneuf River. The hydrology of the area is heavily influenced by snowfall in the surrounding mountains, particularly the Sawtooth and Rocky Mountains. Snowpack levels are closely monitored as they impact streamflow and reservoir levels. In recent years, drought conditions have led to lower snowpack levels and decreased reservoir levels. Record low levels have been seen in several reservoirs during drought years. Seasonal trends show higher reservoir levels during the spring and early summer due to snowmelt, with levels decreasing through the fall and winter. Overall, reservoirs and dams play a significant role in Idaho's water management and the state's economy.