Ground Water Flow Path Study

The purpose of a flow path study is to investigate the fate of constituents in ground water from recharge areas (upland areas) to discharge areas (lowlands, wetlands, or streams). The flow path study for the UMIS NAWQA project is nested within the area encompassed by the Urban Land Use Study, on Shingle Creek, running along a transect from Brooklyn Park, Minnesota to Brooklyn Center, Minnesota (Figure 1). In late June of 1996, preliminary measurements of hydraulic head in the stream bed were conducted and pore-water samples were analyzed in the field to determine concentrations of nitrate and iron. Those preliminary measurements indicated that the stream loses and gains water from the surrounding sandy river-terrace aquifer, and that phreatic plants (specifically large willow trees) along the banks of the stream may have substantial effects of ground-water flow and chemistry in the vicinity of the stream.

Six multiport piezometers (each having four ports) were installed in May and June of 1997 to evaluate ground-water quality with depth in the surficial aquifer along the ground-water flowpath (Figure 2). The flowpath wells were sampled three times (July of 1997, October of 1997, and August of 1998). Water samples were analyzed to determine concentrations of major ions, nutrients, pesticides, volatile organic compounds, radon, tritium, and CFCs.