Ground water and streamflow in the Nett Lake Indian Reservation, northern Minnesota, 1995-97

Abstract

The Nett Lake Indian Reservation, about 164 square miles in area, is in northern Minnesota. About 300 people live in Nett Lake Community, about 100 people live in Palmquist Community, and a few people live in other parts of the Reservation. Water resources in the Reservation include: (1) ground water in sand and gravel aquifers and bedrock aquifers; (2) Nett Lake; (3) streams in the Nett Lake River watershed; and (4) wetlands that comprise about one-half of the area of the Reservation. Ground-water sources in the Reservation consist of sand and gravel aquifers and bedrock aquifers. Buried sand and gravel aquifers are important sources of water. Reported yields for wells completed in these aquifers are as much as 60 gallons per minute. Reported yields for wells completed in bedrock aquifers are as much as 34 gallons per minute. The Reservation is located within the Little Fork River Basin. Streams that flow into and out of Nett Lake are in the Nett Lake River watershed, a subbasin of the Little Fork River Basin. Most of the discharge into Nett Lake is from Lost River and Woodduck Creek; a small amount of discharge into Nett Lake is from several other small streams. Discharge from Nett Lake is to the Nett Lake River. Ground water in buried sand and gravel aquifers in the vicinity of three community wells and a closed landfill east of Nett Lake Community may have moved from the landfill toward the community wells. Ground water near Nett Lake locally discharged into the lake through underlying peat that ranges in thickness from 3 to 12 feet. Two Palmquist Community wells probably are not hydraulically connected to shallow ground water in the vicinity of a nearby closed landfill. The wells are located more than 2,000 feet away and are completed in a bedrock aquifer overlain by 124-154 feet of clay. The concentrations of the trace metals iron and manganese exceeded their respective U.S. Environmental Protection Agency Secondary Maximum Contaminant Level limits in water from three and six wells sampled, respectively. All but 3 of 63 VOCs (volatile organic compounds) analyzed for in water from seven wells sampled had concentrations less than the MDL (method detection limit) of 0.2000 ( μ g/L except for di-bromo-chloro-propane, which had a concentration less than the MDL of 1.000 ( μ g/L. The detected VOCs were phenols, benzene, and 1,1- dichloroethane. The sources of these VOCs may have been leachate from nearby closed landfills. Benzene, the only one of the three detected VOCs with an established MCL (Maximum Contaminant Level), had a concentration that was one order of magnitude less than its MCL of 5 ( μ g/L. The stage-discharge relations for Nett Lake River and Woodduck Creek were usable for estimation of daily mean discharge for each stream. Six discharge measurements made in the Lost River indicate that discharge in this stream could be substantially greater or smaller than concurrent discharge in Woodduck Creek.