Results of Deer Creek, Carlton County, Minnesota, Groundwater Seepage Investigation

Abstract

Deer Creek is a small perennial stream located in Carlton County and is tributary to the Nemadji River. In the early 1990’s beaver constructed a large dam on private property in Sec. 19, T. 47 N., R.16 W. located on the Wrenshall 7.5 minute quadrangle. According to the land owners, groundwater seepage and discharge of sand to the surface began about the time the beaver arrived. The dam was apparently washed out at least twice. On July 4, 1999, the dam was overtopped and washed out during a series of large thunderstorms. The beaver repaired the dam, but apparently during 2001, representatives of the Minnesota Department of Natural Resources removed a beaver dam that impounded a large pond a short distance upstream. This dam was destroyed with dynamite and the rapid drainage of the large pond washed out the dam lower in the drainage. Groundwater discharge is occurring around the perimeter of the former pond. The discharge is focused at discrete points that are easily identified by sand volcanoes. The sand volcanoes are located along fault scarps that are the surface expression of rotational slumps. This report summarizes the results of an investigation of groundwater seepage along a reach of Deer Creek, Carlton County, Minnesota. The groundwater seepage is causing excessive turbidity, which affects all aspects of stream ecology and contributes large amounts of sediment to the Nemadji River.