Overview

Lake Keesus is a 237-acre, mesotrophic spring-fed lake in Waukesha County. It has good to very good water quality; however, secchi disk water clarity readings have been decreasing, indicating increased nutrient loading to the lake (WDNR, 1994). The lake is a complex basin of outwash deposits and is drained by a small ditched stream tributary to the Oconomowoc River. The lake consists of four shallow basins and two deep basins. Frontage is high ground except for the marshy outlet valley and the ditched inlet valley to the north. The fishery consists of pan fish and largemouth bass, with northern pike and walleyes complementing the catch. An abundant population of small bullheads indicates use problems. The residents have relied upon mechanical harvesting and the use of aquatic herbicides and algacides for controlling nuisance growth of algae and aquatic macrophytes. Public access is provided by a DNR public boat launch on the south side of the lake. Ice fishing is popular here, with yellow perch and bluegills dominating the catch. Adjoining shallow marsh and shrub swamp provide suitable habitat for waterfowl and upland game birds. In 1993. WDNR managers identified sensitive areas, where the aquatic plant community is protected from disturbance.

Over the last five years, the riparian property owners have been fairly active. A lake management district weathered a serious attempt by people wishing to disband the group shortly after it was formed. An advancement association for the district also exists; some of the issues being addressed include public lake access, development of an aquatic plant management plan, designation of sensitive areas, and control of a blue-green alga species (Gleotrichia).

In 1994, the lake district prepared, and WDNR approved, an aquatic plant management plan. The plan recommends using a mechanical harvester to control nuisance rooted aquatic plant growth. The lake has also been plagued by algal blooms that irritate swimmers. The blue-green algae species Gleotrichia is probably causing the problem. The aquatic plant management plan recommends treating the shoreline with algacides to control it. WDNR lake managers are requiring pre- and post- treatment assessments to prove chemical effectiveness.

In 1993, WDNR staff identified four sensitive areas on Keesus Lake, as per NR 107 (Aquatic Plant Management Program) guidelines. Property owners living adjacent to these areas were notified of the management implications. The management restrictions addressed activities such as aquatic herbicide use, dredging, filling, piers/boardwalks, pea gravel blankets and aquatic plant screens.

Zebra mussels veligers have been identified in the watershed, but none so far in Keesus Lake. Given the nature of the hydrologic connection between Keesus Lake and the other lakes in the system, it is unlikely zebra mussels will enter the lake by migrating upstream; it is more likely they will spread by attachment to boats.

Date  2002

Author   Aquatic Biologist

Historical Description

A complex basin in outwash deposits, drained by a small ditched stream tributary to the Oconomowoc River. There is no impounding structure. The lake consists of four shallow basins and two deep
basins. Frontage is, high ground except for the marshy outlet valley and the ditched inlet valley to the north. The fishery consists of pan fish and largemouth bass, with northern pike and walleyes complementing the catch. An abundant population of small bullheads is a use problem. The lake has also been treated chemically for weed control for several years. Public access is questionably provided by three platted roads and a right-of -way. Several boat livery resorts and a Milwaukee Boys' Club camp provide a degree of use. Ice fishing is popular here with yellow perch and bluegills dominating the catch. Adjoining shallow marsh and shrub swamp provide suitable habitat for both waterfowl and upland game birds. Source: 1963, Surface Water Resources of Waukesha County Keesus Lake T8N, R18E, Sections 11 and 14 Surface Acres = 237, S.D.F. = 2.32, Maximum Depth = 42 feet

Date  1963

Author   Surface Water Inventory Of Wisconsin

General Condition

Keesus Lake (WBIC 852400) was assessed during the 2018 listing cycle; new total phosphorus and chlorophyll sample data were clearly below the 2018 WisCALM listing thresholds for the Recreation use and the Fish and Aquatic Life use. This water was meeting these designated uses and was not considered impaired.

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

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 Keesus is located in the Oconomowoc River watershed which is 130.86 mi². Land use in the watershed is primarily agricultural (24.90%), forest (19.70%) and a mix of wetland (16.90%) and other uses (38.40%). This watershed has 136.99 stream miles, 2,858.66 lake acres and 11,105.19 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.