Reconnaissance geology and hydrology on the Nett Lake Indian Reservation, Minnesota

Abstract

The Nett Lake Indian Reservation is in northern Minnesota, about 210 miles north of Minneapolis and St. Paul. The village of Nett Lake (population about 300) is the only community on the reservation. This report is the result of an investigation made to provide a central water source for the village, at the request of the Public Health Service of the U.S. Department of Health, Education, and Welfare. The climate of the area is continental, characterized by cool, subhumid summers and long, severe winters. The average annual precipitation is 24.2 inches. Altitudes in the area range from about 1,190 feet above mean sea level in the Little Fork River channel on the west border of the reservation to about 1,550 feet on top of the Vermilion end moraine, just south of Nett Lake. During the latter part of the Pleistocene Epoch most of the area was inundated by the waters of glacial Lake Agassiz. The area is now drained by the Little Fork River which flows north into the Rainy River, thence into Lake of the Woods, and eventually into Hudson Bay. The geologic units in the Nett Lake area consist of unconsolidated deposits of Recent and Pleistocene age and crystalline rocks of Precambrian age. Most ground water in the Nett Lake area occurs in three different zones: 1) surficial sand and gravel deposits, 2) lake sand underlying compact lake clay, and 3) bedrock fractures. The lake sand underlying the compact clay is the best source of ground water for the village of Nett Lake. It occurs in a small channel immediately west of the village, and it ranges in depth from about 11 to 30 feet below land surface and in thickness from 0 to about 3 feet. The water level is near the surface. A test well yielded 30 gpm (gallons per minute). Two 15 gpm wells would not exceed the long-term yield of the aquifer and would be adequate for the needs of the village.