Lakes & Streams

Geneva Lake is one of Wisconsin's largest (5,262 acres) and deepest (140-foot maximum depth) lakes. Located in Walworth County, the Lake is renowned for good water quality and hosts a remarkably diverse array of high-quality recreational opportunities. For its size, Geneva Lake has a very small watershed (less than 30 square miles).

The Commission completed numerous studies over the past decades providing valuable insight into Lake-related issues, including a 1985 water quality study and 2008 lake management plan.

Geneva Lake stakeholder organizations are currently updating the Lake’s management plan with the Commission’s assistance and with funding through a Wisconsin Department of Natural Resources Surface Water Grant awarded to the Geneva Lake Conservancy. As grantee, the Conservancy is the organization ultimately responsible for executing the grant scope. However, a host of organizations and entities are integral to, and encouraged to participate in, the planning process.

Topics that will be addressed in Lake Geneva Management Plan include:

• Inventory lake data and management actions
  • Aquatic plant community
  • Water quality
  • Tributary sediment deposition
  • Boat traffic and activity
  • Bigfoot Creek study
  • Past lake management efforts
• Quantify stakeholder perceptions and foster cooperation
  • Conduct lake user survey
  • Stakeholder outreach
  • Enhance stakeholder collaboration
• Inventory watershed condition
  • Delineate and characterize Lake watershed
  • Study select tributaries
  • Windwood Creek demonstration
  • Examine stormwater infrastructure

Materials prepared for the plan will be posted here as they become available.

Supporting materials will be posted here as they become available.

Delavan Lake is a 2,072-acre deep lowland lake located within the Town and City of Delavan in Walworth County. The Lake is popular for its recreational use. The Lake is dammed, and its outflow contributes to Turtle Creek and eventually to the Rock River. Both the Lake and Jackson Creek, the Lake’s primary tributary, are listed on the 303(d) impaired waters list for total phosphorus.

The Commission published a lake management plan for the Lake in 2002. Water quality and pollutant loading remain concerns for the Town of Delavan, the Delavan Lake Sanitary District, the Delavan Lake Improvement Association, and other lake stakeholders. The Town and District requested the Commission’s assistance in updating the comprehensive lake management plan to address issues regarding water quality, pollutant loading, aquatic plants, and recreational use. The draft comprehensive lake management plan is currently in preparation.

Topics addressed in the comprehensive lake management plan include:

• Lake conditions
  • Examine water quality trends
  • Evaluate aquatic plant community
  • Monitor recreational use
• Sediment and phosphorus load reduction
  • Phosphorus and sediment capture by wetland ponds
  • Evaluating best management practice effectiveness
  • Phosphorus and sediment capture by lake inlets
  • Examining efficacy of sediment-consumption pellets
• Lake and watershed management
  • Capacity to and benefits of water level fluctuations
  • Integrate recommendations regarding water quality and pollutant loads
  • Recommend strategies to reduce recreational use conflicts
  • Suggest funding sources and opportunities

Materials prepared for the plan will be posted here as they become available.

Supporting materials will be posted here as they become available.

Friess Lake is a 121-acre deep lowland lake located in the Village of Richfield in Washington County. The Oconomowoc River is the Lake’s primary tributary and outlet. The River flows approximately 250 yards downstream to the 16-acre Little Friess Lake. Both lakes support abundant aquatic plant growth in their nearshore areas but also have deep areas that likely do not sustain aquatic plant growth. A 2014 survey observed 20 aquatic plant species on Friess Lake; no such survey has been conducted for Little Friess Lake.

The Friess Lake Advancement Associations and private owners manage aquatic plant growth on Friess Lake to enhance navigation and recreational opportunities, primarily through chemical controls and diver-assisted suction harvesting. To renew its permits to conduct this management, the Association retained the Commission to reevaluate the Lake’s aquatic plant community and update the aquatic plant management plan.

Commission staff plan to survey the aquatic plant communities of Friess Lake and Little Friess Lake in the summer of 2024. The aquatic plant management plan will likely be completed in early 2025. These efforts are supported through a Wisconsin Department of Natural Resources NR 193 Surface Water Grant.

Materials prepared for the plan will be posted here as they become available.

Supporting materials will be posted here as they become available.

Lake Lorraine is a 155-acre seepage lake located in the Town of Richmond in Walworth County. As a seepage lake, the Lake has no outlet stream and its water levels can fluctuate substantially during periods of high and low rainfall. Attaining a maximum depth of 18 feet, the Lake likely supports aquatic plant growth throughout most of its surface area. A 2018 survey observed 14 aquatic plant species in the Lake.

The Lake Lorraine Restoration and Protection Association manages aquatic plant growth on the Lake to enhance navigation and recreational opportunities, primarily through chemical controls. To renew its permits to conduct this management, the Association retained the Commission to reevaluate the Lake’s aquatic plant community and update the aquatic plant management plan.

Commission staff plan to survey the aquatic plant community of Lake Lorraine in the summer of 2024. The aquatic plant management plan will likely be published in early 2025. These efforts are supported through a Wisconsin Department of Natural Resources NR 193 Surface Water Grant.

Materials prepared for the plan will be posted here as they become available.

Supporting materials will be posted here as they become available.

Nagawicka Lake is a 981-acre two-story lake located in the City of Delafield in Waukesha County. The Lake is fed and drained by the Bark River and its water elevation is controlled by an outlet dam. Attaining a maximum depth of 90 feet, the deepest portions of the Lake are likely not capable of supporting an aquatic plant community, but previous surveys have indicated that the shallow nearshore areas support abundant plant growth. A 2016 survey by the Commission observed 32 aquatic plant species, including many sensitive native species.

The City of Delafield manages aquatic plant growth on Lake Lorraine to enhance navigation and recreational opportunities, primarily through mechanical harvesting. To renew its permits to conduct this management, the City retained the Commission to reevaluate the Lake’s aquatic plant community and update the aquatic plant management plan.

Commission staff plan to survey the aquatic plant community of Nagawicka Lake in the summer of 2024. The aquatic plant management plan will likely be published in early 2025. These efforts are supported through a Wisconsin Department of Natural Resources NR 193 Surface Water Grant.

Materials prepared for the plan will be posted here as they become available.

Supporting materials will be posted here as they become available.

Lac La Belle is a 1,164-acre two-story lake located within the City of Oconomowoc and Town of Oconomowoc in Waukesha County. Lac La Belle is the last lake in a chain of six major lakes along the Oconomowoc River system; the River is the primary tributary to and outlet for the Lake. The Lake is quite popular for recreational use and the southern lake shoreline forms the backdrop of the City of Oconomowoc’s downtown.

Lac La Belle was listed on the 2022 303(d) impaired waters list with total phosphorus and polychlorinated biphenyl as pollutants. The Lac La Belle Management District and its partners, particularly the Oconomowoc Watershed Protection Program, are actively implementing projects to address pollutant loading to the Lake. The District has requested the assistance of the Commission in studying phosphorus and water flows to the Lake.

Topics that will be addressed in the study include:

• Monitoring water quality and streamflow on the Lake’s tributaries
• Digitizing the Lake’s bathymetric map
• Updating the Lake-direct watershed delineation
• Developing total phosphorus and water budgets for the Lake
• Prioritizing areas and practices to reduce phosphorus loads

Materials prepared for the plan will be posted here as they become available.

Supporting materials will be posted here as they become available.

The Fox River has its headwaters in southern Washington County and flows largely south for 84 miles to the Wisconsin-Illinois border. Within Wisconsin, Fox River watershed covers 924 square miles across six counties. Plans by the Commission and other entities have addressed water quality, hydrology, water use and supply, and hazard mitigation in the watershed.

The Southeastern Wisconsin Fox River Commission (“SEWFRC”) was established in 1977 by the State of Wisconsin in response to concerns over water resources problems in the Fox River. From 1977 to 2015, SEWFRC had jurisdiction on the Fox River from the City of Waukesha to the Waterford dam. In 2016, SEWFRC expanded its jurisdictional boundary to include an additional 27 miles of the Fox River from Waterford dam to the state line. Due to this expansion, the SEWFRC retained the Commission to:

1. Inventory streambank erosion within the expanded boundary
2. Integrate and compare findings from the expanded area to a prior study conducted within the existing boundary
3. Re-prioritize erosion severity of sites over the entire SEWFRC boundary area
4. Characterize watershed pollutant loading
5. Recommend best management practices and programs to address pollutant loading
6. Publish these findings in a report, which is currently in preparation

North Lake is a 440-acre two-story lake located in the Town of Merton in Waukesha County. The Oconomowoc River is the Lake’s primary tributary and the Lake outlet. Previous Commission studies of the Lake and its watershed include a 2018 nine-key element plan and a 2021 Oconomowoc River watershed nutrient and sediment study.

The North Lake Management District has observed that Lake water clarity has decreased over time and that sediment has accumulated in nearshore areas. Following a 2019 study, the District became concerned that boat-generated waves were linked to these observations.

The District requested the Commission’s assistance in studying how recreational use affects the Lake, including monitoring how boat-generated waves affect water quality, aquatic plants, and lake sediments. This work is supported by three Wisconsin Department of Natural Resources grants. The draft study report is currently in preparation.

Materials prepared for the plan will be posted here as they become available.

Supporting materials will be posted here as they become available.

Lake Comus, a 131-acre shallow impoundment of Turtle Creek located in western Walworth County, was the focus of a 2022 comprehensive lake management plan completed by the Commission. As described in this plan, the Lake has low water clarity, sporadic algal blooms, and a poor aquatic plant community while the Creek is highly turbid with a buildup of mucky sediment. Lake Comus, Turtle Creek, and a tributary of the Creek were listed impaired by total phosphorus on the 2022 303(d) list of impaired waters.

To help address these water quality problems, the Lake Comus Protection and Rehabilitation District has retained the assistance of the Commission to prepare a watershed-based nine-key element plan that builds upon the 2022 comprehensive plan. This nine-key element plan will provide additional information on conditions within Turtle Creek, agricultural practices within the watershed, updated pollutant load modeling, and recommendations to improve water quality. In 2023, Commission staff completed a survey of Turtle Creek with the help of a local volunteer and completed a watershed survey with assistance from Walworth County staff.

The draft nine-key element plan is currently in preparation. Implementing the plan will require community coordination, partnership among stakeholders, farmer-led soil health practices, and innovative watershed projects to make progress towards restoring the water resources of the Turtle Creek watershed.

Materials prepared for the plan will be posted here as they become available.

Supporting materials will be posted here as they become available.

Lake Mary and Lake Elizabeth, commonly known as the Twin Lakes, are in the Village of Twin Lakes in Kenosha County. Water leaving Lake Mary, a 333-acre deep headwater lake, flows downstream through a short channel into Lake Elizabeth, a 715-acre deep lowland lake. The outlet from Lake Elizabeth is a major headwater of Nippersink Creek, the largest tributary of the Fox River and a highly valued stream in Illinois.

The Commission completed a lake management plan for the Twin Lakes in 2009. Since that time, Village of Twin Lakes residents and riparian owners have noted concerns regarding water levels and ice damage to shorelines. With the Commission’s assistance, the Village is currently updating the Lake’s management plan, supported by a Wisconsin Department of Natural Resources Surface Water Grant.

Topics that will be addressed in Twin Lakes Management Plan include:

• Update lake data
  • Watershed characterization
  • Water quality
  • Pollutant load modeling
• Examine lake hydrology
  • Weather information
  • Lake water elevation
  • Water control policies and infrastructure
• Evaluate shoreline
  • Ice damage
  • Potential pollutant sources
  • Recommend protective practices

Materials prepared for the plan will be posted here as they become available.

Supporting materials will be posted here as they become available.

In 2022, the Wisconsin Department of Natural Resources (WDNR) identified high-quality waters (streams, lakes, and wetlands) across Wisconsin: less than 15% of lakes in Wisconsin were designated as high quality. Additionally, the Commission has identified the most significant remaining natural areas in the Region through its Regional Natural Areas Plan. The goals of these designations are to bring attention and funding to protect high-quality waters, since historically the focus has been on restoring impaired waters.

In 2023, the Commission received four WDNR Surface Water Education Grants. The Commission’s grant projects aim to establish a network of well-informed stakeholders from identified high-quality lakes within Walworth and Waukesha Counties. The Commission will provide a toolkit and a practice-based workshop to inform and train stakeholders on lake data inventory, best management practices, and funding, as well as to form connections and inspire protection of these lakes.

The Commission’s main goals across the grants are to:

• Collect information about WDNR-identified high-quality lakes in Walworth and Waukesha Counties and active stakeholder organizations affiliated with these lakes through discussions and interviews with lake stakeholders.
• Educate stakeholders on how to collect information about lake conditions and management. Facilitate learning and communication between similar lake type network members through a practice-based workshop.
• Publish a best management practice toolkit for each lake type.

Materials prepared for the plan will be posted here as they become available.

Supporting materials will be posted here as they become available.

The Wisconsin Department of Natural Resources (WDNR) established the Lake Monitoring and Protecting Network program to support organizations conducting essential lake monitoring activities, such as surveying for aquatic invasive species (AIS) and measuring water quality.

Walworth County has participated in the program since 2021 and has retained the Commission’s service to help conduct lake monitoring as part of their participation. Through this program, the County and Commission have focused their efforts on lakes that have less frequent monitoring activities.

In the summer of 2024, Commission staff will conduct an AIS survey on Lake Ivanhoe and an aquatic plant survey on Honey Lake as well as baseline water quality monitoring on both lakes. All lake monitoring data will be submitted to the WDNR and Commission staff will produce a short report of the study findings that will be available to the public.

Materials prepared for the plan will be posted here as they become available.

Supporting materials will be posted here as they become available.

The Commission assisted the County with obtaining its first Wisconsin Department of Natural Resources (WDNR) Lake Monitoring and Protection Network grant in 2024. However, this grant is largely intended to monitor lakes with public access. Due to the abundance of lightly monitored lakes in Ozaukee County without public access, the County has retained the Commission to conduct invasive species, aquatic plant, and water quality monitoring on lakes and millponds within the County.

Commission staff collect water quality measurements and conduct AIS and aquatic plant surveys on the Thiensville and Grafton millponds of the Milwaukee River as well as a few inland lakes, potentially including Moldenhauer, Hawthorne, and Beekeeper Bog Lakes. All AIS, water quality, and aquatic plant data will be submitted to WDNR databases. The Commission will also produce brief reports on their findings at each millpond and lake that will be made available to the public.

Materials prepared for the plan will be posted here as they become available.

Supporting materials will be posted here as they become available.