3.5.2 Groundwater Quality
Groundwater originates as precipitation that soaks into the ground and eventually reaches the water table and deeper aquifers. The water table is the boundary below which geologic materials are completely saturate with water. Depth to the water table is dependant on the gradient of the water table and surface topography. Where the water table is exposed at the surface, wetlands, lakes, and streams are formed. These water resources can also be perched above the water table by relatively impermeable layers.
Groundwater quality and quantity data are limited for this watershed. The Minnesota Pollution Control Agency (MPCA)’s Ground Water Monitoring and Assessment Program (GWMAP) developed baseline groundwater quality data from 1992-1996 for the Metro area, but the program has been scaled back and minimal follow up work has been completed. Eight of the wells used to assess groundwater quality in the Metro area were located in the watershed. None of the constituents that were of specific concern in the Metro area (nitrate, chloride, volatile organic compounds (VOCs) and arsenic) exceeded standards in the program’s wells in the District. The Hennepin County Groundwater Protection Plan was completed in 1994 and approved by the Board of Water and Soil Resources (BWSR), but has not been adopted by the Hennepin County Board.