Marengo River, Marengo River Watershed (LS12)
Marengo River, Marengo River Watershed (LS12)
Marengo River (2911900)
26.77 Miles
11.74 - 38.51
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.
Coldwater, Cool-Cold Mainstem, No Classification, Macroinvertebrate, Cool-Warm Headwater
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 river is impaired
Recreational Restrictions - Pathogens
Fecal Coliform
Ashland, Bayfield
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.
Class III Trout
Streams capable of supporting a seasonal coldwater sport fishery and which may be managed as coldwater streams.
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.


The Marengo River curves through a region of lakes, wetlands, forest and high hills in the Gogebic Range, then flows down into a region of red clay soils and lands cleared for agriculture, before flowing into the Bad River Indian Reservation to meet the Bad River. The river drains more than 80 square miles of Bayfield county before crossing into Ashland county. Only one impoundment exists on the river. This 5-foot concrete overflow dam is at the head of a scenic rapids and falls area. About a mile below that, an abandoned granite quarry is part of an interesting scenic area that is privately held.

From: Turville-Heitz, Meg. 1999. Lake Superior Basin Water Quality Management Plan. Wisconsin Department of Natural Resources, Madison, WI.

Date  1999

Author   Aquatic Biologist

Marengo River, Marengo River Watershed (LS12) Fish and Aquatic LifeMarengo River, Marengo River Watershed (LS12) RecreationMarengo River, Marengo River Watershed (LS12) Fish Consumption

General Condition

Due to rapid runoff from its rather impervious soils, steep hills and rock outcroppings, the river experiences three-to-four-foot flood crests. Most of the stream is quite open with the only good cover found in deep pools. Stream bottom types vary, with muck and sand predominating in the extreme upper stream areas, rubble, gravel and boulders through the middle portion, while the lower reach is almost entirely unstable sand. Extensive beaver activity deteriorates trout habitat along the upper shrub-marsh areas. Muskrats also use the river as do nesting and migratory waterfowl. As the river passes into Ashland County, the stream passes through large stretches of agricultural lands and the clear water becomes turbid due to streambank pasturing. There are a number of quarries in this watershed, as well as the potential for logging activities. The variety of jurisdictions overseeing land uses can mean variability in management practices.

Past documentation indicates an effluent ditch near the community of Marengo carries septage to the river. The impact of this is unknown, and it is unknown if this ditch is open to human access or poses a risk to wild and domestic animals.

Date  2015

Author  Lisa Helmuth

Impaired Waters

The Marengo River (2911900) from the outlet of Marengo Lake to Bad River Indian Reservation Boundary was assessed during the 2016 listing cycle; fecal coliform data exceeded criteria. This portion of the river is considered impaired.

Date  2015

Author  Aaron Larson

Aquatic Invasives

The Great Lakes Indian Fish and Wildlife Commission released a survey report on purple loosestrife in the Bad River Watershed. The report documents significant loosestrife infestations, the worst of which is around High Bridge and portions of the Marengo River.

Date  2015

Author  Lisa Helmuth


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.



Citizen-Based Stream Monitoring
Collect chemical, physical, and/or biological water quality data to assess the current overall stream health. The data can inform management decisions and may be used to identify impaired waters for biennial lists.
Watershed Mapping or Assessment
The Bad River Watershed Association is sponsoring a project that focuses on community outreach and the formation and direction of a Citizen Involvement Committee to guide the Marengo River Action Plan for the Marengo River watershed. The project is part of a broader Marengo River Watershed Partnership, which will identify, prioritize, and coordinate management actions. Specifically, the Citizen Involvement Committee will compile existing sociological surveys to prioritize public interests, develop conservation incentive program summaries for citizens, hold 5 focus group meetings with targeted audiences, and summarize and integrate focus group feedback into the Plan. The goal is to recruit 25 new members and 10 new organizational leaders through this effort. The final deliverable includes: a final report with 1) sociological survey(s) compilation, 2) conservation program summaries, 3) focus group meeting attendance summaries and minutes, 4) focus group roadmap for Plan integration, and 5) list of new members or leaders recruited.
Monitor Aquatic Biology
Bacteriological monitoring of the Marengo River and tributaries by the Bad River Watershed Association and the Bad River Natural Resource Dept. has shown high levels of E. coli are often present, especially during runoff events. Since 2007, BRWA has sampled E. coli on 162 sampling events across 20 locations in the Marengo River watershed. E. coli levels exceeded 126 colonies/100 ml on 70 occasions at 12 of those sites. E. coli levels exceeded 1000 colonies on 15 occasions at 7 of those sites. Livestock and residential wastewater systems appear to be the sources. The objective of this project is to conduct additional bacteria monitoring consistent with NR 102 to determine if water quality standards are being exceeded, and if so, to consider adding a section of the river to the 303d list of impaired waters. Three sites will be sampled on the Marengo River and its tributaries.
Water Quality Planning
The Marengo River Watershed is located in central Ashland and south central Bayfield counties in the Lake Superior Basin of northern 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

Monitoring Studies

During survey work conducted as part of the coastal wetlands evaluation one rare species of macroinvertebrate was found and overall taxa richness was moderate (5-24 species) (Epstein 1997). At the survey site in Bayfield County, significant pollutant sources were identified from point sources, construction activities, livestock, barnyards and cropland. Significant silting may be affecting habitat quality.

This water was assessed during the 2014 listing cycle; biological sample data (i.e. macroinvertebrate or fish Index of Biotic Integrity (fIBI) scores) clearly met 2014 WisCALM listing thresholds for the Fish and Aquatic Life use.

Five monitoring sites on the river have collected biological data in the past five years (2008 through 2012). Fish IBI data on 2008 through 2013 indicated a mix of Fair, Good and Excellent values at three different stations. A macroinvertebrate value indicated "excellent" condition.

Date  2015

Author  Lisa Helmuth

Watershed Characteristics

Marengo River is located in the Marengo River watershed which is 217.53 miĀ². Land use in the watershed is primarily forest (67.40%), wetland (15.30%) and a mix of grassland (11.60%) and other uses (5.70%). This watershed has 450.89 stream miles, 1,497.18 lake acres and 18,112.32 wetland acres.

Nonpoint Source Characteristics

This watershed is ranked Medium for runoff impacts on streams, Not Available 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

Marengo River is considered a Coldwater, Cool-Cold Mainstem, No Classification, Macroinvertebrate, Cool-Warm Headwater 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.

Cool (Warm-Transition) Headwaters are small, sometimes intermittent streams with cool to warm summer temperatures. Coldwater fishes are uncommon to absent, transitional fishes are abundant to common, and warm water fishes are common to uncommon. Headwater species are abundant to common, mainstem species are common to absent, and river species are absent.

Cool (Cold-Transition) Mainstem streams are moderate-to-large but still wadeable perennial streams with cold to cool summer temperatures. Coldwater fishes are common to uncommon, transitional fishes are abundant to common, and warm water fishes are uncommon to absent. Headwater species are common to absent, mainstem species are abundant to common, and river species are common to absent.

Fish Species

The entire length of the Marengo is considered trout water, with the portion above Marengo Lake supporting a Class II trout fishery and the reaches below the lake supporting a Class III trout fishery. Migrating sea lamprey from Lake Superior historically have spawned in the lower reaches of the Marengo River.

Date  2015

Author  Lisa Helmuth