Mauthe Lake, East and West Branches Milwaukee River Watershed (MI06)
Mauthe Lake, East and West Branches Milwaukee River Watershed (MI06)
Mauthe Lake (38200)
70.19 Acres
Natural Community
Natural communities (stream and lake natural communities) represent model results that use predicted flow and temperature based on landscape features and related assumptions. Ranges of flow and temperature associated with specific aquatic life communities (fish, macroinvertebrates) help biologists identify appropriate resource management goals. Wisconsin Natural Communities.
Deep Lowland
Year Last Monitored
This is the most recent date of monitoring data stored in SWIMS. Additional surveys for fish and habitat may be available subsequent to this date.
This lake is impaired
Mercury Contaminated Fish Tissue, Impairment Unknown, Excess Algal Growth
Mercury, Total Phosphorus
Fond Du Lac
Trout Water 
Trout Waters are represented by Class I, Class II or Class III waters. These classes have specific ecological characteristics and management actions associated with them. For more information regarding Trout Classifications, see the Fisheries Trout Class Webpages.
Outstanding or Exceptional 
Wisconsin has designated many of the state's highest quality waters as Outstanding Resource Waters (ORWs) or Exceptional Resource Waters (ERWs). Waters designated as ORW or ERW are surface waters which provide outstanding recreational opportunities, support valuable fisheries and wildlife habitat, have good water quality, and are not significantly impacted by human activities. ORW and ERW status identifies waters that the State of Wisconsin has determined warrant additional protection from the effects of pollution. These designations are intended to meet federal Clean Water Act obligations requiring Wisconsin to adopt an 'antidegradation' policy that is designed to prevent any lowering of water quality - especially in those waters having significant ecological or cultural value.
Impaired Water 
A water is polluted or 'impaired' if it does not support full use by humans, wildlife, fish and other aquatic life and it is shown that one or more of the pollutant criteria are not met.

Fish and Aquatic Life

Current Use
The use the water currently supports. This is not a designation or classification; it is based on the current condition of the water. Information in this column is not designed for, and should not be used for, regulatory purposes.
Deep Lowland
Deep lowland lake describes the depth and location of the lake in a watershed. These variables affect the lakes response to watershed variables.
Attainable Use
The use that the investigator believes the water could achieve through managing "controllable" sources. Beaver dams, hydroelectric dams, low gradient streams, and naturally occurring low flows are generally not considered controllable. The attainable use may be the same as the current use or it may be higher.
Fish and Aquatic Life - waters that do not have a specific use designation subcategory assigned but which are considered fishable, swimmable waters.
Designated Use
This is the water classification legally recognized by NR102 and NR104, Wis. Adm. Code. The classification determines water quality criteria and effluent limits. Waters obtain designated uses through classification procedures.
Default FAL
Fish and Aquatic Life - Default Waters do not have a specific use designation subcategory but are considered fishable, swimmable waters.

Historical Description

Source: 1969, Surface Water Resources of Fond du Lac County Mauthe Lake, T13N, R19E, Sections 11, 12 Surface Acres = 63, S.D.F. = 2.25, Maximum Depth = 22 feet.

This relatively shallow, marsh-bog edged lake is the heart of the Kettle Moraine State Forest, with the Kettle Moraine State Forest Headquarters located on the west shore, and an intensively developed camping, swimming, picnic area located on the east shore. All the shoreline is publicly owned. The inlet is the East Branch Milwaukee River, which flows from Long Lake, five miles upstream. There is a fixed-spillway dam (head of 3 feet) on the outlet which maintains a constant water level in the lake. The water is slightly brown-stained, and algae blooms appear to be more frequent in the past few years. Vegetation is moderately abundant, with a narrow band of water lily around most of the lake, except in the artificially developed swimming area. Muskrats are common, with some puddle ducks such as bluewing teal and wood duck nesting in association with the estimated 40 acres of adjoining wetland. No hunting is allowed on the lake. Since 1955, there has been no closed season, size limit, or bag limit of fish on the lake. Primary game fish are northern pike, largemouth bass, and walleye, with the major panfish being black crappie, bluegill, and perch. Carp are present, but do not constitute a problem at the time. Use of outboard motors on the lake is prohibited. Several plantings of northern pike and walleye have been made in recent years to evaluate their effect on fishing. A fishing pier in the public use area is very popular, and 20 large trees have been placed on the shoreline of the lake in two locations to serve as fish concentration and harvest areas.

Date  1969

Author   Surface Water Inventory Of Wisconsin

Mauthe Lake, East and West Branches Milwaukee River Watershed (MI06) Fish and Aquatic LifeMauthe Lake, East and West Branches Milwaukee River Watershed (MI06) RecreationMauthe Lake, East and West Branches Milwaukee River Watershed (MI06) Fish Consumption

General Condition

Mauthe Lake Beach, Kettle Moraine SF - Northern Unit 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.

Date  2017

Author  Ashley Beranek


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.


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 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

Mauthe Lake is located in the East and West Branches Milwaukee River watershed which is 266.00 miĀ². Land use in the watershed is primarily agricultural (35.50%), wetland (19.20%) and a mix of forest (17.90%) and other uses (27.40%). This watershed has 312.44 stream miles, 2,023.13 lake acres and 32,107.47 wetland acres.

Nonpoint Source Characteristics

This watershed is ranked High for runoff impacts on streams, High 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.

Natural Community

Mauthe Lake is considered a Deep Lowland under the state's Natural Community Determinations.

Natural communities (stream and lake natural communities) represent model resultsand DNR staff valiation processes that confirm or update predicted conditions based on flow and temperature modeling from historic and current landscape features and related variables. Predicated flow and temperatures for waters are associated predicated fish assemblages (communities). Biologists evaluate the model results against current survey data to determine if the modeled results are corect and whether biological indicators show water quaity degradation. This analysis is a core component of the state's resource management framework. Wisconsin's Riverine Natural Communities.

Deep lowland lake describes the depth and location of the lake in a watershed. These variables affect the lakes response to watershed variables.