East Twin River, East Twin River Watershed (TK02)
East Twin River, East Twin River Watershed (TK02)
East Twin River (84000)
15.91 Miles
10.49 - 26.40
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.
Warm Mainstem, COOL-Warm Mainstem
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
Impairment Unknown
Total Phosphorus
Kewaunee, Manitowoc
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.
Fish and Aquatic Life - waters that do not have a specific use designation subcategory assigned but which are considered fishable, swimmable waters.
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.


Much of the East Twin River watershed is in agricultural use. The soils are erodible and little natural buffer areas exist along the river. Nonpoint sources of water pollution include streambank and woodlot pasturing, gully erosion, construction sites and croplands. Fish management personnel believe these nonpoint sources are adding sediment and nutrients to the river, and that restoring wetlands and reducing agricultural runoff would have beneficial effects on the fishery (WDNR, 1982).

Historic reductions in the percentage of forested and wetland vegetation have resulted in a watershed that lacks adequate opportunities for infiltration and retention of precipitation and snow melt resulting in flashy runoff which overwhelms existing stream channels and aquatic habitat. This excessive runoff also strips valuable sediments and nutrients from the terrestrial environment and delivers them to our streams and lakes where they result in degraded water quality and poorer habitat which can kill sensitive and intolerant fish and aquatic invertebrates. Flashy runoff also limits the amount of water available to sustain adequate flows during drought. Restoration efforts should focus on increasing the overall percentage of forested and wetland vegetation in this watershed to restore a more natural hydrologic regime and minimize the impacts of flashy runoff and an altered hydrologic regime.

From: Willman, Guy and Mike Toneys. 2001. The State of the Lakeshore Basin. Wisconsin Department of Natural Resources, Madison, WI.

Date  2001

Author  Michael Toneys

Land Use

Lower sections of the East Twin River (Manitowoc County) flow through mostly agricultural land, although some sections are buffered by grass. Most of the urban development along the river is in the lowest sections in the city of Two Rivers and the village of Mishicot. A dam in Mishicot blocks fish movement in the river. However the dam does prevent further upstream migration of sea lamprey and allows for easier lamprey treatment in the East Twin. Bottom sediments in the lower sections of the East Twin range from sand to cobble, although silt can be present in depositional portions of the river (Weber et al. 1966).

Date  2012

Author  Steven Hogler

Facilities Management

The Mishicot wastewater treatment plant is the only municipal sewage treatment facility discharging to the East Twin River. The facility was upgraded in 1983, which improved the general water quality below its
discharge (Russo, 1985). Recently, the plant has had problems with excessive influent flows, sewer bypassing, and exceeding of ammonia limits. Ammonia toxicity below the outfall is a concern and may need to be addressed through facility planning. WDNR staff have recommended applying a Great Lakes or cold water community classification for water quality standards to the East Twin River below Mishicot (Doelger, 1993).

There are no direct industrial discharges to the river, althought Krohn Dairy operates an activated sludge treatment plant that discharges about 14,000 gallons of wastewater per day to an unnamed tirbutary. The Two Rivers landfill is a suspected source of contaminants to area surface waters.

From: Willman, Guy and Mike Toneys. 2001. The State of the Lakeshore Basin. Wisconsin Department of Natural Resources, Madison, WI.

Date  2001

Author  Michael Toneys

East Twin River, East Twin River Watershed (TK02) Fish and Aquatic LifeEast Twin River, East Twin River Watershed (TK02) RecreationEast Twin River, East Twin River Watershed (TK02) Fish Consumption

Impaired Waters

The 2018 assessments of the East Twin River from the confluence with West Twin River to Mishicot Dam showed impairment by phosphorus; new total phosphorus sample data exceeded the 2018 WisCALM listing criteria for the Fish and Aquatic Life use. Available biological data did not indicate impairment (i.e. no macroinvertebrate or fish Index of Biotic Integrity (IBI) scored in the "poor" condition category). Based on the most updated information, no change in the existing impaired waters listing was needed.

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.



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.
Monitor Aquatic Biology
Monitor to follow up on mIBI values (Fair and declining in 2011), and phosphorus values (Clearly Exceed in 2011).
Partnership Project
Lakeshore Natural Resources Partnership (LNRP) is sponsoring a project to continue to support the Friends of the Twin Rivers by engaging area citizens in educational activities in the Twin Rivers watersheds. Project final deliverables include: all data collected, agendas and minutes for planning meetings, presentations, newsletters and educational materials provided to the public. Specific project activities include: 1) Hold beach clean-up event; 2) Host a rain barrel workshop; 3) Host Water Action Volunteer (WAV) training sessions; 4) Host a river clean-up event; 5) Host educational seminars; 6) Host volunteer Restore the Shore Work Day events and write annual reports detailing invasive species found and habitat improvement project ideas in the watersheds.
Educate and engage residents
Lakeshore Natural Resources Partnership (LNRP) proposes to build upon past efforts and further develop the newly formed Friends of the Twin Rivers group by 1) providing targeted watershed education and outreach to local community members including directly engaging high school students, 2) expanding the network of student and community volunteers collecting water quality data throughout the watershed at strategic locations following the Water Action Volunteers monitoring protocols, and 3) leading a strategic planning process for the Friends of the Twin Rivers group. LNRP will facilitate at least two community education events, one symposium for high school students, and quarterly community meetings. LNRP will submit a final report summarizing the project to the Department.
Restore Riparian Habitat
Woodland Dunes Nature Center and Preserve proposes to improve habitat in the watershed of the East and West Twin Rivers by documenting opportunities for habitat improvements and developing an effective program for reaching, educating, and working with landowners to do so. Specifically, Woodland Dunes will develop a plan for increasing the capacity to improve the riparian areas within the lower reaches of the East and West Twin Rivers. Woodland Dunes will develop a plan for increasing outreach to landowners in the area, offering information on habitat management or restoration including onsite visits and site-specific advice.
Educate and engage residents
Woodland Dunes Nature Center shall supplement and build on previous work by partners to raise public awareness and participation in water stewardship in the East and West Twin Rivers. Specifically, Woodland Dunes will offer educational programs and action projects including WAV trainings, storm drain marking, river and beach clean-up events, guide West Twin River pontoon tours, and river paddles. Woodland Dunes will also coordinate with the City of Two Rivers to provide storm water management education to increase awareness of storm water pollution impacts to the East and West Twin Rivers. Fliers, newsletters, website, and newspaper articles will advertise the events.
Partnership Project
The Lakeshore Natural Resources Partnership, Inc. (LNRP) proposes to form and strengthen partnerships with and between river protection organizations in the Lakeshore Basin. Specifically, the LNRP plans to collaborate with each river-protection organization and sponsor special events that feature a keynote speaker of some notoriety, develop and publish a quarterly LNRP newsletter, and develop the LNRP website in order to increase its ability to communicate with its constituents.
Engage Volunteers in Monitoring/Restoration
The Woodland Dunes Nature Center, Inc. proposes to organize, educate, and sustain a citizen volunteer stewardship group for the East and West Twin River watersheds that will set up a program based on Wisconsin\00BFs Water Action Volunteers (WAV) stream monitoring program. The project elements and deliverables will be completed as described in the project proposal submitted to the Department and dated May 1, 2006. Amendment #1: Woodland Dunes Nature Center will assist the City of Two Rivers Stormwater Task Force in development of a comprehensive stormwater public education and outreach program. Woodland Dunes staff will meet with the task force to pritorize education topics and develop or modify existing materials to fit the needs of the Two Rivers community.
Rivers Planning Grant
This project is to do an initial assessment on the upper reaches of the East Twin River (WBIC 84000) to determine if there are any impairments and if additional data are needed to determine if the river should be added to the 303(d) list. The timing of this project is excellent because the fisheries folks are planning to assess the fish community in the upper reaches of the East Twin River this summer so the monitoring can be used in conjunction with the fish data to determine the current overall stream health.
Monitor or Propose 303(d) Listing
1) The West Twin River will be monitored at five locations: one site in each assessment unit 9948, 9949, 9950, 18050, & 18051. 2) A habitat assessment will be conducted in each assessment unit. Also continuous dissolved oxygen (DO) and temperature monitoring will be done for one week in each assessment unit. 3) Habitat assessments and continuous DO monitoring will be done in July or August 2011.
Monitor or Propose 303(d) Listing
Monitor to follow up on Clearly Exceeding phosphorus values and Poor mIBI.
Engage Volunteers in Monitoring/Restoration
Brown and Kewaunee Counties hire an aquatic invasive species coordinator similar to Manitowoc County’s coor­dinator.

Standards Details

The East Twin River is a large, low gradient stream (2.7 to 3.3 feet per mile) that flows 34.5 miles through mostly agricultural land on its way to Lake Michigan. Upper sections in Kewaunee County are slightly stained and classified as either Class 1 or Class 2 trout waters (WDNR 1995). Stream corridors are well buffered by forests and numerous groundwater seeps are present. Stream bottom sediments range from all sand to all silt with bedrock and gravel present in some streams (WCD 1966).

Date  2012

Author  Steven Hogler

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

Invertebrate rankings in the East Twin River range from fair to very good for the Hilsenhoff Biotic Index (Gansberg 1995). Habitat evaluation scores ranged from fair to good. Both indexes indicate good water quality. This is markedly different than water quality measurements in the 1930’s and 1940’s when poor water commonly reduced Dissolved Oxygen Levels (D.O.) to near zero resulting in many fish kills (Bartz 1938 and 1944). Construction of an improved sewage treatment plant in Mishicot, and restricting discharge from a diary certainly has led to improved water quality in the river.

Fish surveys have been conducted infrequently on the East Twin River, but those studies have found a wide variety of gamefish which range from trout in upper reaches, to smallmouth bass and northern pike in middle reaches to Lake Michigan species in the areas nearest to the lake (Fago 1985, Hogler 2000). Forage species are abundant throughout the system. A large fish kill in 1982 as result of a sea lamprey treatment killed at least 21,000 fish (Brege 1983). Minnows, suckers and bullheads were the most commonly killed species with substantially fewer gamefish noted.

Date  2012

Author  Steven Hogler

Watershed Characteristics

East Twin River is located in the East Twin River watershed which is 183.58 mi². Land use in the watershed is primarily agricultural (57.30%), grassland (16.50%) and a mix of wetland (14.70%) and other uses (11.50%). This watershed has 314.70 stream miles, 12,446.75 lake acres and 14,181.41 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.

Fish Consumption Advice

Fish flesh screening for toxic chemical contamination revealed that PCB concentrations exceeded FDA health standards in carp, northern pike, and rainbow trout between 1978 and 1990. A fish consumption advisory is in effect from the river's mouth to the Mishicot dam for carp, catfish, yellow perch, northern pike, crappie,smallmouth bass and Lake Michigan salmon and trout. The WDNR publication, Health Guide for People who eat Sport Fish from Wisconsin Waters, details consumption advisory information. Anglers should examine the guide regularly for possible changes in the advisory.

Date  2012

Author  Steven Hogler

Natural Community

East Twin River is considered a Warm Mainstem, COOL-Warm Mainstem 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.

Warm Mainstem waters are moderate-to-large but still wadeable perennial streams with relatively warm summer temperatures. Coldwater fishes are absent, transitional fishes are common to uncommon, and warm water fishes are abundant to common. Headwater species are common to absent, mainstem species are abundant to common, and river species are common to absent.

Fisheries & Habitat

The East Twin River is 34.5 miles long with a watershed of 133 square miles. It is a low gradient (2.7 feet per mile) stream with a 19-year average flow of 78.6 cubic feet per second (USGS, 1992). The river generally has fair to good water quality and most of it supports a diverse warmwater fishery. Biologists have identified 61 species of fish in the Twin Rivers basin, including the threatened greater redhorse (Moxostoma valenciennesi). The redside dace (Clinostomus elongatus), a species on Wisconsin's "watch list," is also present. Northern pike, smallmouth bass, and channel catfish are frequently taken. Anadromous salmon andtrout seasonally run as far upstream as the Mishicot dam, which serves as an important sea lamprey barrier. In its headwaters, 7.6 miles of the river are Class I and II trout waters. The dam and impoundment at Mishicot may have some impact on water quality and the movement of downstream fishes. The dam is being reconstructed and will be managed by the Village of Mishicot (Koch, 1995). The dam will be designed to
prevent lamprey movement and reproduction upstream (Meyers, 1995). Impoundments commonly develop poor water quality due to sediment deposition. Additional land management practices may be needed to control polluted runoff in the East Twin River Watershed to minimize degradation of the pond.

Date  2012

Author  Michael Toneys