Is Wisconsin protecting its groundwater?
By Neil C. Koch
Wisconsin governments, state, county, and townships havedone little or nothing to protect groundwater from being contaminated by nitrate and PFAS (forever chemicals), and the quality in many areas is getting worse each year. In the Kewaunee County area the aquifer became very contaminated before steps were taken to do something about the contamination. Groundwater is depleted faster than it can be replenished in some areas in Wisconsin.
In the past most of the groundwater contamination came from farm animal waste, fertilizer, and pesticides. Today as urban sprawl has established housing developments throughout the state, septic systems are now a major groundwater contaminator. Human waste goes into a septic system which is two cement tanks where the solids break down then the liquid waste goes to a land area called a drainfield where the liquid moves through the soil. In housing developments sixty percent of the recharge to the groundwater comes from septic system drainfield waste water.
Septic system drainfield waste water contains viruses, nitrate, PFAS and household chemicals. Nitrate can cause colorectal cancer and thyroid dysfunction.
Algoma township west of Oshkosh established a sanitary sewer district and removed all septic systems in housing developments. This needs to be done state wide to protect the groundwater.
Septic systems are pumped periodically and spread on agricultural land areas that Wisconsin Department of Natural Resources (DNR) has selected. In Dunn County the DNR has selected over 400 sites where human waste from septic systems can be land spread. DNR has many requirements that must be met before DNR selects a site. In Dunn County 150 sites do not meet DNR standard for percolation which can not be greater than 6 inches per hour (in/h). When the septic system waste water moves through the soil too fast the waste does not have enough time to break down and moves down to the groundwater.
If there are 150 failed septic land spreading sites in Dunn County there could be 7,000 failed sites in Wisconsin. Michigan and Florida require septic waste to be taken to municipal waste treatment systems. The Wisconsin State legislature needs to require septic waste be taken to municipal treatment systems.
Some septic waste companies are already taking the waste to municipalities.
Periodically counties state wide reassess conditions and each time groundwater continues to deteriorate and reports indicate no ordinances have been passed to stop the deterioration.
Two townships, Menomonie and Dunn, in Dunn County passed ordinances to protect recharge to groundwater and to keep the aquifer from being contaminated. To protect the recharge to groundwater a developer is encouraged to leave as much land open so rainfall can recharge the groundwater. The ordinance used a soils percolation map of Dunn County where I classified ninety one soil types into five percolation rates from excellent to poor. All counties should have a soils percolation map so ordinances could be passed state wide to protect the groundwater. Ordinances could be passed where companies that might contaminate the groundwater could not be located in the three highest soil percolation areas.
In several areas in Wisconsin the water level in aquifers is declining and recharge is not enough to replenish the aquifer.
The state needs to control the addition of new wells that can be pumped at a high rate so that the aquifer will not be pumped dry or impact nearby rivers and lakes.
It is time for Wisconsin governments to stop the groundwater from becoming more contaminated.
Neil C. Koch is a retired hydrologist with the United States Geological Survey
