Perch Lake Beach, Perch Lake, Lower Willow River Watershed (SC02)
Perch Lake Beach, Perch Lake, Lower Willow River Watershed (SC02)
Perch Lake Beach, Perch Lake (2488300)
0.04 Miles
0 - 0.04
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.
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.
St. Croix
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.
Shallow headwater 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.
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.


Perch Lake is a hardwater, seepage lake, landlocked and having the greatest maximum depth of any lake in St. Croix County. Though managed for brook and rainbow trout, it also has populations of walleyes, largemouth bass, bluegills, black crappies, pumpkinseeds, green sunfish, yellow bullheads, carp and white suckers. A public access is located at the lake's south end off a town road. There is a boat livery available and private development consists of 5 cottages. A number of ducks of both the puddle and divers groups use the lake during migratory periods though they seldom nest here. Local ordinance restricts motor horsepower size and motor boat use hours.

Perch Lake T30N R19W, S28 Surface Acres = 42.5 S.D.F. = 1.42 Maximum Depth = 63 feet Source: 1961, Surface Water Resources of St.Croix Co.

Date  1961

Author   Aquatic Biologist

Historical Description

Perch Lake is recommended as an Outstanding Resource Water to be included in NR 102 by Department staff. The lake has excellent water clarity, a diverse aquatic plant community and the ability to support a two story fishery. The lake ecosystem is threatened by the potential rural residential development of the watershed and shoreline. A significant portion of the shoreline is currently utilized as a private recreational park and the park could potentially be developed if this use changes.

Date  1992

Author   Aquatic Biologist

Perch Lake Beach, Perch Lake, Lower Willow River Watershed (SC02) Fish and Aquatic LifePerch Lake Beach, Perch Lake, Lower Willow River Watershed (SC02) RecreationPerch Lake Beach, Perch Lake, Lower Willow River Watershed (SC02) Fish Consumption

General Condition

Perch Lake 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.

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.



Improve Public Access
St. Croix Co. proposes to construct a main park entrance road, one-way park access roads to and from Perch Lake, six parking areas and two infiltration basins. Grading and erosion control measures are designed to protect the water quality of Perch Lake.
Land Acquisition
St. Croix County will acquire 19.8 acres with all rights to land on Perch Lake that will expsnd it's day-use park called Homestead Parklands. The county purchase of the Onstott property will include 100 feet of shoreline at the north end of the property on Perch Lake. 268 feet of shoreline on Perch Lake at the south end of the Onstott property will be protected with the purchase of a conservation easement on 9.2 acres of the property.
Land Acquisition
St. Croix County shall participate in the Lake Protection Grant Program by purchasing approximately 67.05 acres of land in the Perch Lake watershed for lake protection purposes.
Lakes Protection Grant
Perch Lake should be considered a high priority to receive lake protection grants for the protection of environmentally sensitive lands. which will facilitate water quality protection.

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

Perch Lake is located in the Lower Willow River watershed which is 164.38 miĀ². Land use in the watershed is primarily agricultural (32.10%), forest (25.40%) and a mix of grassland (23.70%) and other uses (18.80%). This watershed has 99.33 stream miles, 2,139.74 lake acres and 2,482.81 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

Perch Lake Beach, Perch Lake is considered a Two-Story 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.

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