IDAHO RESERVOIR REPORT

Last Updated: December 20, 2025

In recent observations of Idaho's reservoirs and dams, there appears to be a trend of below-average water levels when compared to historical averages for this time of year. A notable example includes Coeur d'Alene Lake's gage height, currently standing at 28 feet, which is higher than its average of 25.98 feet, indicating higher water levels than usual. Conversely, other significant water bodies such as Henrys Lake, Milner Lake, and the Salmon River Canal Co reservoir are exhibiting lower than usual levels, with their current gage heights being 14, 9, and 9 feet respectively, compared to their averages of 15.57, 10.27, and 23.81 feet. This suggests a mix of above and below-average water conditions across the state, with particular concern for areas with reduced water storage.

These abnormal conditions can be attributed to the recent climate trends, as Idaho has just experienced its warmest fall on record. This, coupled with a sobering water forecast, has created a challenging backdrop for water management, likely impacting snowpack accumulation and subsequent river flows. The Little Wood Reservoir near Carey is a striking case, with a significant decrease in storage levels; the current storage is 13,380 acre-feet, markedly less than the average of 17,024 acre-feet. Similarly, CJ Strike Reservoir and Lucky Peak Lake near Boise are slightly below their average gage heights, though not as dramatically. These variations underscore the effect that above-average temperatures and potentially reduced snowpack have on water resources. Understanding these trends is vital, as they influence water availability for agricultural, ecological, and residential needs, and could signify more significant water management issues if such patterns 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.