Bullhead Lake, Lower Manitowoc River Watershed (MA02)
Bullhead Lake, Lower Manitowoc River Watershed (MA02)
Bullhead Lake (68300)
69.52 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 Seepage
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
Impairment Unknown, Excess Algal Growth, Eutrophication
Mercury, Total Phosphorus
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 Seepage
Deep seepage lake describes the depth and hydrologic charactertistics of the lake. 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.
Supported Aquatic Life
Waters that support fish and aquatic life communities (healthy biological communities).
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.


Bullhead Lake is a 67-acre landlocked seepage lake lying in an outwash plain, with hard, alkaline water
and a maximum depth of 40 feet. The mean depth is 13 feet. There are 1.07 miles of shoreline of which
0.01 miles are publicly owned. Twelve acres of wooded wetlands adjoin the lake. The watershed
encompasses 2.0 square miles. Hybrid Muskellunge were stocked in 1980, but it is unlikely any remain.
Walleye have been stocked throughout the 1980s. Largemouth and smallmouth bass are common, and
panfish are abundant. This lake is listed under a consumption advisory because of mercury levels.

DNR staff treated the lake with aluminate on August 23, 1978. As part of a research project, aluminum
sulfite was applied through the process of hypolimnetic injection. (See WDNR Tech. Bulletin #153). The treatment worked for almost 10 years before phosphorus levels reached pretreatment levels.
In 1986, the Bullhead Lake Association requested guidance from the WDNR due to high levels of
phosphorus causing increased algal productivity. WDNR provided technical assistance for a second
aluminum sulfite treatment applied on October 8, 1988, at four to six feet below the water surface in an area of the lake with depths greater than 12 feet. The treatment proved successful, although phosphorous levels as of 1991 are increasing.

Bullhead Lake is monitored by volunteers as part of self-help monitoring program. Secchi disc readings
have been taken since 1986. Since 1990, Bullhead Lake has been part of the expanded self-help
monitoring program. Dissolved oxygen, pH, phosphorus, and secchi data are now available from this
expanded volunteer data collection program. Bullhead Lake received a High ranking using the NPS criteria developed for lakes and is therefore eligible as a Priority Lake Project under the NPS program. Using the phosphorus classification scheme, Bullhead Lake falls into Class 1A (phosphorus sensitive). The water quality of the lake is threatened as recent data shows phosphorus values increasing just three years after the aluminum sulfite treatment. Cropping practices in the drainage area are degrading the water quality.

The implementation of best management practices in the lake's watershed would protect the investment the lake district made through the application of aluminum sulfite and protect this high use lake and its aesthetic value. The Bureau of Integrated Science Services (SS), in conjunction with the Northeast Region Lake Biologist, collected a sediment core from Bullhead Lake during the summer of 1991. The core was to be used to better characterize the trophic history of Bullhead Lake. This information can then be used to establish achievable water quality goals and better realize the potential for a full recovery of the lake. This technique has proven useful for the management and understanding of other lake systems in Wisconsin. The status for this core data is unknown. The lake association applied in August 1995 and received a lake planning grant to characterize land use practices that impact water quality in Bullhead Lake. The district limnologist is working with the lake association to determine impacts of sediment delivery to the lake following significant rain events. Please refer to the district Watershed Management files for specific data on the lake study.

Date  2002

Author   Aquatic Biologist

Historical Description

Source: 1968, Surface Water Resources of Manitowoc County Bullhead Lake, T19N, R21E, Section 19 Surface acres - 67, S.D.F. = 1.07, Maximum depth = 35 feet.

A landlocked seepage lake lying in an outwash plain. The clear water is hard and alkaline. The bottom is largely gravel and muck. The lake was chemically treated in 1957 to rectify a stunted panfish problem. Subsequent stocking of muskellunge now provides one of the few fisheries of this type in east central Wisconsin. Largemouth bass, bluegills and perch also contribute to the fishery. There is a county park with 260 feet of frontage and parking. Water skiing and the use of live bait for fishing are prohibited. There are 12 acres of adjoining wetland. Hunting is permitted and moderate numbers of both puddle and diving ducks provide some shooting.

Date  1968

Author   Surface Water Inventory Of Wisconsin

Bullhead Lake, Lower Manitowoc River Watershed (MA02) Fish and Aquatic LifeBullhead Lake, Lower Manitowoc River Watershed (MA02) RecreationBullhead Lake, Lower Manitowoc River Watershed (MA02) Fish Consumption

Impaired Waters

Bullhead Lake (WBIC 68300) was placed on the impaired waters list for Mercury in 1998 and total phosphorus in 2012. The 2018 assessments showed continued impairment by phosphorus; new total phosphorus sample data exceeded the 2018 WisCALM listing thresholds for the Recreation use and Fish and Aquatic Life use. Chlorophyll-a sample data clearly exceeded the REC use thresholds, but clearly met the FAL use threshold. Based on the most updated information, no change in existing impaired waters listing was needed.

Date  2017

Author  Ashley Beranek

Impaired Waters

Bullhead Lake (68300) was placed on the impaired waters list for Mercury in 1998 and total phosphorus in 2012. The 2016 assessments showed continued impairment by phosphorus; total phosphorus and chlorophyll sample data exceeded 2016 WisCALM listing thresholds for the Recreation use, but did not exceed Fish and Aquatic Life thresholds. Based on the most updated information, no change in existing impaired waters listing is needed.

Date  2015

Author  Aaron Larson


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.



Monitor Paleocore
One sediment core was taken in Bullhead Lake in 1991. Diatom analysis was done, final report submitted 2008.
Monitor Fish Tissue

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

Bullhead Lake is located in the Lower Manitowoc River watershed which is 168.33 miĀ². Land use in the watershed is primarily agricultural (47%), wetland (19.50%) and a mix of grassland (17.90%) and other uses (15.50%). This watershed has 264.70 stream miles, 2,910.36 lake acres and 19,995.06 wetland acres.

Nonpoint Source Characteristics

This watershed is ranked High for runoff impacts on streams, Not Ranked 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

Bullhead Lake is considered a Deep Seepage under the state's Natural Community Determinations.

Natural communities (stream and lake natural communities) represent model results and 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 seepage lake describes the depth and hydrologic charactertistics of the lake. These variables affect the lakes response to watershed variables.