Trout Lake, Manitowish River Watershed (UC16)
Trout Lake, Manitowish River Watershed (UC16)
Trout Lake (2331600)
3864.29 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.
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.
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.
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.


Trout Lake, in the Manitowish River Watershed, is a 3,864.21 acre lake that falls in Vilas County. This lake is an outstanding/exceptional resource water under NR102 under the Fisheries Program. This lake is managed for fishing and swimming and is currently not considered impaired.

Date  2011

Author   Aquatic Biologist

Historical Description

Source: 1963, Surface Water Resources of Vilas County Trout Lake, T-41-N, R-7-E, Sections 5, 6, 7, 8 and 17,

Trout Lake is a drainage lake of moderate fertility, having clear slightly alkaline water of high transparency. Bottom materials consist mainly of gravel and sand, with rock and some muck. Both the inlet and the outlet streams are considered navigable. Trout Lake is one of the deepest inland lakes in Wisconsin and the largest lake in Vilas County. The principal warm water species present are the muskellunge, walleye, largemouth bass, smallmouth bass and pan fish. The lake also supports a cold water population composed of lake trout, rainbow trout, cisco and whitefish. The lake has a state forest area located on the shore line. Public access is possible by means of town and county roads with parking facilities, or by navigating either the inlet or outlet streams. Public use facilities consist of 12 resorts, one private resort, one boat rental establishment, two WCD camping areas, two youth camps, and several WCD picnic areas. There are 62 cottages located on the shore line. The University of Wisconsin has a Biology Research Station located on Trout Lake. Diving ducks use this lake on both their spring and fall migration. Canadian geese are known to use the lake on their fall migration. Even though there are commercial and private developments on the shore line, Trout Lake still retains excellent aesthetic qualities as approximately 96 per cent of the shore line is in public ownership.

Area = 3,870 Surface Acres, Maximum Depth = 115 feet, S.D.F. = 1.83

Date  1963

Author   Surface Water Inventory Of Wisconsin

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

Trout Lake is located in the Manitowish River watershed which is 268.60 miĀ². Land use in the watershed is primarily forest (66.90%), wetland (19.10%) and a mix of open (13.30%) and other uses (0.70%). This watershed has 212.08 stream miles, 22,943.16 lake acres and 33,727.48 wetland acres.

Nonpoint Source Characteristics

This watershed is ranked Low for runoff impacts on streams, Low for runoff impacts on lakes and Low for runoff impacts on groundwater and therefore has an overall rank of Low. 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

Trout 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.

Maps of Watershed