IDAHO RESERVOIR REPORT

Last Updated: January 2, 2026

Recent observational data on Idaho's dams and reservoirs reveal a mix of storage levels with some facilities showing abnormal readings for this time of year. Priest Lake, Henrys Lake, and Milner Lake are reporting slightly lower gage heights than their historical averages at 1 foot, 15 feet, and 9 feet respectively, suggesting a potential deficit in water input relative to expected seasonal norms. Conversely, Coeur d'Alene Lake is slightly above its average at 26 feet. The most notable deviation is observed at the Salmon River Canal Co Reservoir near Rogerson, with a gage height of 10 feet, significantly below its average of 23.72 feet. Mud Lake and Payette Lake also show lower gage heights than average, which may indicate reduced inflows or higher water demand. Meanwhile, Mackay Reservoir, Little Wood Reservoir, CJ Strike Reservoir, and Lucky Peak Lake are close to their average levels, with Little Wood Reservoir recording a storage of 13,380 acre-feet against an average of 17,024 acre-feet.

These conditions could be tied to various factors, including this year's snowpack levels and river flows that feed into the reservoirs. Low snowpack can lead to decreased runoff and reduced reservoir recharge during the spring melt, while higher-than-average temperatures can lead to increased evaporation rates. The significant shortfall at the Salmon River Canal Co Reservoir, for example, could be due to lower snowmelt or altered water management practices, such as increased water extraction for irrigation. Local weather patterns and climate conditions, including droughts, also play a critical role in affecting water storage levels. Given the mixed conditions among Idaho's water storage facilities, further investigation into regional hydrological data and local water usage policies would provide a more comprehensive understanding of the current reservoir statuses and guide water resource management decisions. It's crucial to continue monitoring these resources, as they are essential for local ecosystems, agriculture, recreation, and hydroelectric power generation.

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.