GCC Report to the Legislature
Groundwater is abundant in Wisconsin and available in sufficient amounts throughout most of Wisconsin to provide adequate water supplies for most municipal, industrial, agricultural and domestic uses. However, groundwater pumping can lower water levels in an aquifer and in certain settings reduce groundwater discharge to surface water bodies connected to the aquifer
Water quantity trends and topics
Water use reporting showed that the largest category of groundwater withdrawals was municipal public water supplies, accounting for 91 billion gallons in 2018, down from 92 billion in 2017. The second largest category of groundwater withdrawal in the state was agricultural irrigation, totaling 82 billion gallons in 2018, increasing from 64.6 billion gallons in 2017.
Groundwater/surface water interactions
In many areas of the state groundwater and surface water are well connected requiring a better understanding of the role water withdrawals have on streamflow and lake water levels.
Several areas of Wisconsin have seen regional drawdowns of the groundwater due to extensive groundwater withdrawals – these drawdowns can affect water availability and water quality.
Department staff track recent and historical precipitation and compare that data to long-term averages to characterize and identify trends. These precipitation patterns are compared to water level readings in monitoring wells statewide. Most of the state has received well above average precipitation in recent years and groundwater data reflects this trend. Groundwater levels are at or near all-time historic highs throughout the state, which is consistent with groundwater flooding reports received by the department in recent years.
Water quantity tools and strategies
Statewide groundwater level network
Water levels collected from the network help scientists and managers evaluate effects of well pumping, the response of groundwater levels to drought or increased precipitation and effects of land-use change on groundwater resources.
Water use data
DNR's interactive map viewer allows the public to access information about approved surface and groundwater withdrawals, existing and pending high capacity wells, water quantity monitoring by various agencies and locations of groundwater protection features throughout Wisconsin. DNR's water use search tool allows users to find individual or aggregate water withdrawals from high capacity wells and surface water withdrawals.
Little Plover River Model and Watershed Enhancement Project
A state-of-the-art groundwater flow model was developed as a tool for understanding the interactions between groundwater withdrawals and streamflow in the Little Plover River basin in Wisconsin's Central Sands region. As stakeholders work together to evaluate management options to ensure sustained flows in the river, the model allows “what-if” evaluations of possible water use or land-use changes.
Central Sands Lakes Study
Under 2017 Wisconsin Act 10, the legislature requested that the DNR evaluate and model the potential impacts of groundwater withdrawals on three lakes in Waushara County. As part of the study the DNR will determine if there is the potential for significant impacts to the lake's average seasonal levels as a result of groundwater withdrawals.
Chippewa County Groundwater Model
Chippewa County worked with Wisconsin Geological and Natural History Survey (WGNHS) and the U.S. Geological Survey (USGS) to conduct a groundwater resources study in western Chippewa County to evaluate the relationship between groundwater withdrawals and water levels in nearby wells. The model will be used to evaluate how changes in pumping rates, placement of new high-capacity wells and changes to the landscape affect wells and streams in the future.
Groundwater Coordinating Council