Direct measurement of groundwater flow and quality as a lake management tool

Abstract

The flow of groundwater into and out of lakes can have a substantia] impact on their hydrologic and nutrient budgets. The use of a simple device (a manometer) sensitive to differences in water pressure allows delineation of potential zones of contribution (inflow) and recharge (outflow). Application of simple seepage meters allows quantification of groundwater flows. Pore water extracted from lake sediments in zones of contribution can be chemically analyzed to allow quantification of nutrient loadings to the lake via the groundwater. In 1987, these devices were used to measure groundwater flow to 11 Massachusetts lakes. Groundwater inflow accounted for between 1 to 57 percent of the total lake inflows. Inflows were greatest in kettlehole lakes and least in stream impoundments. Seepage meter measurements were significantly affected by season and local shoreline topography. Distance from shoreline and sediment nature were also factors. A recommended approach for using these devices is considered. Direct measurement of groundwater flow and quality is essential to the proper characterization of lakes without major tributaries and to the evaluation of available management techniques. © 1988 North American Lake Management Society.