Dakota County keeps track of drinking water trends across its land area by conducting groundwater studies. The information helps the County understand current issues with its drinking water supply and prepare for future challenges.
Hastings Area Nitrate Study (HANS)
The Hastings Area Nitrate Study (Phase I) was conducted from 1999 through 2003 to determine the extent and sources of nitrate contamination problems in the City of Hastings and the surrounding areas. One quarter of the private wells tested as part of the study exceeded the drinking water standard for nitrate (10 milligrams per liter) and another quarter contained elevated levels of nitrate (3–10 milligrams per liter). Nitrate can come from a variety of sources, but in the Hastings Area Nitrate Study, it was found to be very strongly associated with row crop agriculture. The Vermillion River was found to play a role in transporting contaminated water downstream.
In 2007, Dakota County conducted Phase II of the HANS project. Dakota County led the project in cooperation with the University of Minnesota Extension, Dakota County Soil and Water Conservation District, Minnesota Department of Agriculture, U. S. Department of Agriculture's Natural Resources Conservation Service, the City of Hastings and others to prevent future groundwater contamination within the Vermillion River Watershed. See the Hastings Area Nitrate Study and Figures.
Ambient Groundwater Quality Study
The Ambient Groundwater Quality Study began in 1999 to establish a water quality baseline in the County and to track changes in water quality over time. From 1999 to 2003, the same set of bedrock wells completed in the Prairie du Chien Aquifer and the Jordan Aquifer were sampled for general chemistry and contaminants related to industrial processes, nitrate and pesticide use. In 2004, wells screened in the sand and gravel aquifer were added to the study.
In 2004, laboratory analysis by the United States Geological Survey showed levels of pesticides and nitrate of concern. A Fact Sheet explains details about the study and its findings. See the Ambient Groundwater Study.