Dane County's abundant surface water resources are monitored and assessed primarily by the Wisconsin Department of Natural Resources (WDNR). Major streams and lakes are classified into categories based on the aquatic organisms present. These classifications provide an indication of water quality and fishery conditions.
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Agricultural and urban land uses contribute to nutrient rich runoff reaching surface waters. Impervious surfaces and removal of wetlands also increases the flow of stormwater to local waterways. Explore issues facing our surface water and see maps of degraded water resources.
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Effective water quality planning depends on long-term assessment and monitoring. The Capital Area Regional Planning Commission uses long-term datasets to evaluate regional trends.
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Learn about practices meant to protect the region's streams, shorelands, and lakes.
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Interactive Water Resource Maps

Interactive maps allow access to up-to-date information on water quality. Visit these sites to learn more about available data for specific water bodies.

Dane County

Land and Water Resources Viewer: An interactive county map showing watershed boundaries, thermally sensitive areas, cold water communities and more.

Wisconsin Department of Natural Resources (WDNR)

Surface Water Data Viewer: Interactive map with monitoring sites and data. Datasets include chemical, physical, and biological data.

Water Condition Viewer: Interactive map with biotic indices and additional information relating to assessments and management. Shows locations of TMDL and Nine Key Element plans.

Wisconsin Water Quantity Data Viewer: Quantity data collected by WDNR, the USGS, and the Wisconsin Geological and Natural History Survey. Data available include well applications and approvals, high capacity withdrawal locations, groundwater protection features, and springs.

WiDNR Open Data Portal: GIS datasets for Wisconsin

United States Geological Survey (USGS)

USGS National Water Information System (NWIS) Mapper: Surface water sites monitored by USGS. This includes water gages that measure stream discharge throughout the county.

Water Quality Plan Reports

Wetlands of Dane County Wisconsin (1974)

This report inventoried existing wetlands in Dane County. It put wetlands in the context of surrounding uplands and watersheds to highlight unique qualities of each wetland. The report summarizes wetland ecosystems and ecological concepts and developed plant community maps for individual wetlands.

Surface Water Quality Conditions (2014)

In 2014, CARPC published a report covering Surface Water Quality Conditions in Dane County.  Historically, pollution control has focused on point sources. Targeting individual discharges (e.g. from waste water treatment plants, factories, etc.) through permits has effectively reduced those pollutants from reaching surface waters and thus improved surface water quality. The largest issues impacting surface water quality now relate to nonpoint sources - impacts of disperse land use and land management practices. Water bodies are also influenced by changes to water levels and flow (hydrologic regimes). Increased runoff from impervious surfaces negatively impacts waterbodies. Reducing runoff volume would help address both quantity and quality issues since high flows also carry large amount of pollutants.

Key Findings

Water resource monitoring conducted over the last three decades illustrates a few important stream, lake, and groundwater quality findings as the basis for future actions and work in the region:

  • Despite the significant growth and development over the last three decades, in general, surface water quality in streams is not declining and is actually improving for various parameters and in many locations due to wastewater treatment plant upgrades and other point source pollution controls. More recent improvements in some areas have also resulted from improved land management and conservation practices. While much has been accomplished in this regard, more work is needed.
  • Over-fertilization and sedimentation of our lakes and streams from rural and urban nonpoint source stormwater runoff continues to be a problem. These impacts are more difficult to measure and remedy since they cannot usually be traced to a single point or origin. Priority Watershed Projects, local stormwater management ordinances and plans, and agricultural conservation practices are being pursued which implement strategies for reducing runoff and pollution from these varied sources. The Rock River TMDL and associated nutrient trading opportunities are good examples of the innovative and cost-effective measures
    being developed for addressing this problem. This collaborative approach should be considered as a model in other parts of the region as well – to help prevent impairment of waters as well as improve conditions where opportunities permit.
  • Groundwater indicates worsening trends, especially increasing nitrates from overuse of fertilizers and increasing salt concentrations evident in stream baseflow and municipal wells. More attention needs to be directed at reducing the amount of these materials being applied to the land surface. The effect of municipal well water withdrawals on water table levels and stream baseflows is also a growing concern. More efforts are needed to minimize water use along with innovative measures to direct more precipitation into the ground to help make up for these withdrawals – such as enhanced infiltration through engineered soils, rain gardens, and bioretention facilities; along with water supply planning to evaluate and avoid/ minimize wells withdrawals in sensitive areas.
  • The current monitoring program should be continued and also expanded. While certain water resource information problems and improvements have been revealed through monitoring activities, much is still unknown due to limited resource information. A more systematic and tiered approach is needed to assess water resource conditions throughout the region following the WDNR’s Wisconsin Consolidated Assessment Listing Methodology. Continued identification of problems, trends, and success stories through monitoring activities will help provide the necessary information and impetus for directing more efficient and cost-effective resource management plans, projects, and strategies to where they are needed most.

Point Source Inventory and Analysis (2017)

The Point Source Inventory for Dane County lists all regulated wastewater discharges to ground and surface water. These points sources include municipal wastewater treatment plants and industrial discharges. Specific effluent limits, information on receiving water, treatment process, performance, problem assessment, and recommendations were developed for each municipal wastewater treatment plant. Industrial discharges must treat their own waste and do not send their water to a wastewater treatment plant. Specific operation, effluent limits, and recommendations for each discharge are noted. The report presents a summary of findings and recommendations, as well as, discussion of several areas needing continuing efforts: phosphorus, chlorides, “one water”, and regionalization.