“High nitrate levels are a problem for Columbia County’s drinking water and county officials want to do something about it,” said Professor Madeline Gotkowitz, a hydrogeologist at University of Wisconsin – Extension’s Wisconsin Geological and Natural History Survey.
Residents of Columbia County rely exclusively on groundwater for their drinking water. When more than 20% of the groundwater samples from that county had nitrate concentrations higher than the drinking water standard Columbia County officials asked, “Where are the best locations for new wells?” “How deep should they be?”
In response, Prof. Gotkowitz proposed a groundwater flow model for Columbia County. She began her study with the US Geological Survey with a detailed description of the hydrogeology and groundwater resources of the county. She concluded with the preparation of a groundwater model.
The groundwater resource study included the underground water system and the wells that tap it — including every municipal well in Columbia County. It showed how the groundwater is affected by what happens on the land surface. The groundwater model gives Columbia County land and water conservation staff a tool to determine where nitrate pollution is coming from. They can also use the model to test the effect of solutions before they are applied. It is already being used for wellhead protection in towns and villages in the county.
Gotkowitz said, “The model can help answer questions like, ‘What happens to the groundwater if we make a well deeper?’ or ‘Is that proposed gas station too close to the municipal well?’ Answering these questions can guide future land-use decisions.” The county land and water conservation office can arrange for use of the model.