Monitoring of the Clear Lake Aquifer for impacts from agricultural irrigation development and technician assistance

The Clear Lake Aquifer (aquifer) in Sheridan County consists of sand and gravel deposited by ancestral Missouri River and glacial meltwater streams. These deposits form a complex aquifer system with some areas capable of supporting high yield irrigation wells. Irrigation using center pivots grew from about 3000 acres in 1995 to more than 6000 acres in 2014 for the expansion of crops to include: potatoes, soybeans, pinto beans, sugar beets, oilseed crops such as canola and mustard, and corn. Also, yields for crops that are also grown on non-irrigated land, such as wheat and barley, are dramatically increased when grown under irrigation. The aquifer also lies underneath Medicine Lake National Wildlife Refuge and the Northeast Montana Wetland Management District. The wetlands and lakes within this area fall within the Prairie Pothole Region, which provide habitat for migratory birds. The impact of aquifer development for irrigation on surface water resources is poorly understood.