The Rainy Lake watershed is one of 39 watershed units designated by the Minnesota Department of Natural Resources for evaluation of the State 's water resources. Included is an appraisal of the occurrence, quantity, quality, and availability of ground and surface waters. Fifteen percent of the watershed is lakes, 10 acres or larger, that are interconnected by a complex stream network. The abundance of surface water and the wilderness environment make the watershed unique as a recreational area. Lakes in the watershed are major controls on streamflow. They store and slowly release overland runoff, thereby sustaining flow. Surface water supplies used in thewatershed in 1971 totaled 851 million gal, more than half of which was for municipal supplies. A much larger amount was withdrawn and returned directly to streams or lakes after industrial use. Most surface waters have a dissolved-solids concentration of less than 100 mg/liter and are considered soft. Glacial drift is the most favorable source of ground water. In most areas, however, drift is less than 50 ft thick and discontinuous, thereby limiting its reliability as a source of water. Crystalline bedrock, the only alternate source of ground water, is relatively unproductive. Most ground water is of the calcium bicarbonate type, commonly hard, and, in places, contains excessive amounts of iron and manganese. (Woodard-USGS)
Additional Publication Details
USGS Numbered Series
Water resources of the Rainy Lake watershed, northeastern Minnesota
13 maps on sheet :col. ;85 x 141 cm. folded in envelope 30 x 24 cm.