IDAHO RESERVOIR REPORT

Last Updated: January 23, 2026

Idaho's reservoirs and dams are critical for the state's water management, especially considering agriculture, power generation, and flood control. As of the latest observations, certain reservoirs are exhibiting abnormal conditions that could be consequential for the state. Priest Lake, at the outlet near Coolin, shows a significant drop in gage height, currently at 0 ft compared to its average of 1.95 ft. Similarly, the Coeur d'Alene Lake and Henry's Lake are slightly below their average gage heights, while Milner Lake at Milner Dam and the Salmon River Canal Co reservoir near Rogerson display more notable deficits. Mud Lake near Terreton also indicates a lower measurement. Contrasting these, Mackay Reservoir near Mackay is slightly above its average. However, Little Wood Reservoir near Carey, CJ Strike Reservoir near Grand View, and Lucky Peak Lake near Boise are close to their average gage heights, whereas Payette Lake at McCall is significantly below the norm. These deviations may be linked to the region's snowpack and river flow conditions, which are essential for replenishing the reservoirs.

Cross-referencing with external data sources reveals that a mid-winter dry spell across the Pacific Northwest, as reported by opb.org, and concerns over a weak snowpack in the Northern Utah region, which often affects nearby states including Idaho, as per cachevalleydaily.com, could be influencing the abnormal reservoir levels. Weatherbug.com's mention of a tranquil weather pattern worsening the drought depiction nationwide adds to the concern, as reservoirs depend on precipitation and runoff to maintain levels. Substack.com's discussion on ephemeral waters in New Mexico, while focused on a different state, illustrates the broader context of water resource challenges in the western United States. Given these conditions, Idaho's water management authorities may need to prepare for potential water scarcity and consider the impact on agriculture, ecosystems, and urban supplies if the trends continue.

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.