By Neil C. Koch
Wisconsin governments, state, county, and townships have done little or nothing to protect groundwater, 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 control 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. In housing developments sixty percent of the recharge to the groundwater comes from septic waste drainfield water. Septic drainfield water contains viruses, nitrate, PFAS (forever chemicals) 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 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. There are many requirements that must be met before sites are selected. In Dunn county 150 sites do not meet DNR standard for percolation which can not be greater than 6 inches per hour (in/h). If there are 150 failed septic land spreading sites in Dunn county there could be 7,000 failed sites in Wisconsin. When percolation rates are greater than 6 in/h contaminates do not break down and move down to the groundwater and shallow wells. Michigan and Florida require septic waste to be taken to municipal waste treatment systems. The Wisconsin State Legislature needs to require septic waste to be taken to municipal treatment systems.
Periodically counties statewide 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. 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 statewide to protect the groundwater.
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 pumping 500 gallons per minute or more 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 retired hydrologist with the
United States Geological Survey
N7238 520th St Menomonie, WI
715-235-4250