Overview

Lake Monona drains a highly urbanized area and much of its shoreline has been developed. Water quality of this large drainage lake is affected by urban polluted runoff as well as the nutrient loading from Lake Mendota and its watershed. The Dane County Water Quality Management Plan prepared by the Dane County Regional Planning Commission provides more detail on nonpoint source pollution problems in the Yahara lakes.

Recreational use of Lake Monona is intense, with boaters, water skiers, sail boaters, wind surfers, anglers and swimmers taking advantage of the lake's attributes. The lake has a diverse fishery of perch, panfish, largemouth bass, northern pike, walleye and muskellunge. However, a fish consumption advisory exists for certain fish in the lake.

· In-Lake Phosphorus Levels and Macrophyte Growth: Herbicides and algacides have been used extensively--legally and illegally-- to combat algae blooms and excessive aquatic plant growth. The algae blooms and excessive plant growth are not a new phenomena: algae blooms were reported as early as 1888 and chemical treatment with copper sulfate to control algae was begun in 1918. At one time the city of Madison discharged wastewater effluent into the lake. That point source was eliminated with the construction of the Nine Springs wastewater facility, which discharges to Badfish Creek. Consequently, phosphorus levels have decreased in Lake Monona and water quality has improved. Improved water clarity, however, has stimulated increased aquatic plant growth.

Abundant rooted aquatic plant growth has historically occurred in Lake Monona, particularly in Monona Bay and Turville Bay. Eurasian water milfoil (Myriophyllum spicatum), a non-native aquatic plant having less fisheries value than native plants, invaded the lake in the last 50 years. The density of plant growth declined during a period in the late 1970s due to generally poor water clarity and dense summer algae blooms. In the 1980s aquatic plant growth, particularly milfoil, has been resurgent due to improved water clarity. During summer 1996, curly leaf pondweed was observed in as great or greater numbers than Eurasian water milfoil. Because the lake's sediment contains large quantities of nutrients, milfoil and curly leaf pondweed growth will likely continue to be a problem, particularly if water clarity continues to improve.

Over the years Lake Monona has been treated with more than 1.5 million pounds of copper and arsenic compounds to manage aquatic plant growth. Analysis of the core samples indicates a similar trend of decreasing concentrations of these compounds in lake sediments. Chemical spraying to manage aquatic plants is now regulated by WDNR under Administrative Code NR 107, Aquatic Plant Management, to protect overall water quality and aquatic habitat.

Date  2002

Author   Aquatic Biologist

Overview

In-Lake Contaminant Concentrations: Chloride levels in the lake have slowly increased since the 1960s. Chloride levels in Monona are higher than in Lake Mendota, reflecting the greater proportion of urban runoff received by Monona. Sodium levels have been relatively steady over the last 25 years. Continued increases of sodium and chloride levels could change the species of algae and aquatic plants found in the lake and is a concern.

Portions of the lake have been filled with sediment in the past. Some of this fill material may include toxic substances. Due to elevated levels of mercury in walleye samples, a fish consumption advisory exists. The city of Madison Public Health Department identified Starkweather Creek as one source of mercury contamination in the lake. The department conducted sediment core sampling in 1987 to identify the extent of mercury and sediment in the lake. Recent core samples show decreasing mercury deposition over time. These decreasing concentrations indicate the possibility of reduced bioaccumulation in fish.

Polychlorinated biphenyls were detected in sediment samples collected in 1987, with the highest concentration located along the north shore of Monona Bay. The north shore of the bay is also a mercury hot spot. A possible source for the PCBs and mercury is a large storm sewer outfall near the sampling site. Arsenic and copper compounds were also measured in the core samples. Fish monitoring for PCBs and mercury through WDNR's fish consumption advisory program will continue indefinitely.

Date  2002

Author   Aquatic Biologist

Historical Description

Source: 1985, Surface Water Resources of Dane County,WI: WI-DNR Lake Monona T7N, R10E

A large, deep drainage lake, Lake Monona is the second in the series of morainic dammed lakes of the Yahara River valley. The outlet is natural, without an impounding structure. The watershed below Lake Mendota which drains into Lake Monona is highly developed. Storm water runoff and input from the fertile Yahara River result in a high level of nutrient loading. Herbicides and algaecides have been used extensively in Lake Monona in an attempt to control algae blooms and excessive weed growth, but have proven to be only temporary cures. Improvement in water quality was noted following the bypass of sewage effluent from the City of Madison. The lake has a history of carp problems. Boating, water skiing, sailing, swimming, and fishing are possibleon Lake Monona. Ample public access is available at eight city parks and at numerous boat launching sites. The railroad fills and road fills across Monona Bay provide good bank fishing sites. Recent stocking of hybrid muskie has been successful and legal-sized fish are now being caught regularly. Lake Monona supports a diverse fishery with 36 species and 8 unspecified or hybrid fishes present. Fish species: lake sturgeon, longnose gar, bowfin, cisco, northern pike, hybrid muskie, common carp, golden, emerald, and common shiner, bluntnose and fathead minnow, white sucker, black, yellow, and brown bullhead, channel catfish, burbot, brook silverside, white bass, bigmouth buffalo, rock bass, green sunfish, pumpkinseed, bluegill, smallmouth and largemouth bass, white and black crappie, sand, Iowa, and johnny darter, yellow perch, logperch, walleye, freshwater drum, and mottled sculpin.

R10E Surface acres 3,274, SDF = 1.54, Maximum depth = 64 ft

Date  1985

Author   Surface Water Inventory Of Wisconsin

General Condition

Lake Monona BB Clark Beach was placed on the impaired waters list for E. coli related recreational restrictions in 2014. This beach was assessed for the 2018 listing cycle; E. coli data sample data were clearly below the 2018 WisCALM listing thresholds for the Recreation use. This beach was meeting this designated use and was not considered impaired. It was proposed for delisting in 2018.

Date  2017

Author  Ashley Beranek

Impaired Waters

Lake Monona was evaluated for phosphorus and algae every two years between 2012 and 2022. Phosphorus levels were found to be too high, which was reflected in algal blooms. The TMDL restoration plan was approved in 2011.

Lake Monona was placed under a special fish consumption advisory for PFOS in 2020; this lake had a listing of PFOS in fish tissue placed on the 2022 Impaired Waters List.

Date  2022

Author  Ashley Beranek

Impaired Waters

Lake Monona - Schluter Beach was evaluated for bacteria in the 2022 cycle; E. coli levels were above listing thresholds as outlined in 2022 WisCALM. This beach was added to the 2022 Impaired Waters List.

Date  2022

Author  Ashley Beranek

Impaired Waters

Bernies Beach was listed for high E. coli levels in 2008 and delisted when levels were lower in 2014. When evaluated in 2018 E. coli levels were still good, but in the 2020 cycle levels were high again so the beach is proposed for listing.

Date  2019

Author  Ashley Beranek

Impaired Waters

Lake Monona Olbrich Park Beach was placed on the impaired waters list for Recreational Restrictions due to E. coli in 2008. The 2018 assessments showed continued Recreational Restrictions due to E. coli; new E. coli sample data clearly exceeded the 2018 WisCALM listing thresholds for the Recreation use. Based on the most updated information, no change in the existing impaired waters listing was needed.

Date  2017

Author  Ashley Beranek

Impaired Waters

Lake Monona Esther Park Beach was placed on the impaired waters list for Recreational Restrictions due to E. coli in 2014. The 2018 assessments showed continued Recreational Restrictions due to E. coli; new E. coli sample data clearly exceeded the 2018 WisCALM listing thresholds for the Recreation use. Based on the most updated information, no change in the existing impaired waters listing was needed.

Date  2017

Author  Ashley Beranek

Impaired Waters

Lake Monona Hudson Park Beach was placed on the impaired waters list for Recreational Restrictions due to E. coli in 2014. The 2018 assessments showed continued Recreational Restrictions due to E. coli; new E. coli sample data clearly exceeded the 2018 WisCALM listing thresholds for the Recreation use. Based on the most updated information, no change in the existing impaired waters listing was needed.

Date  2017

Author  Ashley Beranek

Impaired Waters

Lake Monona Olin Park Beach was placed on the impaired waters list for Recreational Restrictions due to E. coli in 2008. The 2018 assessments showed continued Recreational Restrictions due to E. coli; new E. coli sample data clearly exceeded the 2018 WisCALM listing thresholds for the Recreation use. Based on the most updated information, no change in the existing impaired waters listing was needed.

Date  2017

Author  Ashley Beranek

Impaired Waters

Brittingham beach was listed for E. coli in 2012.This beach was assessed in 2014 and E. coli data did not exceed 2014 WisCALM listing criteria so it was delisted. E. coli levels were good when evaluated in 2018, but in 2020 levels were too high, prompting listing.

Date  2017

Author  Ashley Beranek

Condition

Wisconsin has over 84,000 miles of streams, 15,000 lakes and milllions of acres of wetlands. Assessing the condition of this vast amount of water is challenging. The state's water monitoring program uses a media-based, cross-program approach to analyze water condition. An updated monitoring strategy (2015-2020) is now available. Compliance with Clean Water Act fishable, swimmable standards are located in the Executive Summary of Water Condition in 2018. See also the 'monitoring and projects' tab.

Reports

Recommendations

Management Goals

Wisconsin's Water Quality Standards provide qualitative and quantitative goals for waters that are protective of Fishable, Swimmable conditions [Learn more]. Waters that do not meet water quality standards are considered impaired and restoration actions are planned and carried out until the water is once again fishable and swimmable

Management goals can include creation or implementation of a Total Maximum Daily Load analysis, a Nine Key Element Plan, or other restoration work, education and outreach and more. If specific recommendations exist for this water, they will be displayed below online.

Monitoring

Monitoring the condition of a river, stream, or lake includes gathering physical, chemical, biological, and habitat data. Comprehensive studies often gather all these parameters in great detail, while lighter assessment events will involve sampling physical, chemical and biological data such as macroinvertebrates. Aquatic macroinvertebrates and fish communities integrate watershed or catchment condition, providing great insight into overall ecosystem health. Chemical and habitat parameters tell researchers more about human induced problems including contaminated runoff, point source dischargers, or habitat issues that foster or limit the potential of aquatic communities to thrive in a given area. Wisconsin's Water Monitoring Strategy was recenty updated.

Grants and Management Projects

Monitoring Projects

Watershed Characteristics

Lake Monona is located in the Yahara River and Lake Monona watershed which is 93.73 mi². Land use in the watershed is primarily suburban (24.80%), urban (23.90%) and a mix of agricultural (14.50%) and other uses (36.90%). This watershed has 101.97 stream miles, 6,275.33 lake acres and 5,158.72 wetland acres.

Nonpoint Source Characteristics

This watershed is ranked Not Available for runoff impacts on streams, Not Available for runoff impacts on lakes and High for runoff impacts on groundwater and therefore has an overall rank of High. This value can be used in ranking the watershed or individual waterbodies for grant funding under state and county programs.However, all waters are affected by diffuse pollutant sources regardless of initial water quality. Applications for specific runoff projects under state or county grant programs may be pursued. For more information, go to surface water program grants.