Willow River, Upper Willow River Watershed (SC03)
Willow River, Upper Willow River Watershed (SC03)
North Fork Willow River (2606900)
0.88 Miles
47.97 - 48.85
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's Riverine Natural Communities.
Cool-Cold Mainstem
Year Last Monitored
This is the most recent date of water monitoring stored in the SWIMS system. 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.
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.


Willow River flows southwest into Lake St. Croix. Five flowages are impounded on this stream: the New Richmond (16 foot head darn), Mounds (50'), Burkhardt (101'), Little Falls Flowage (27') and Mallileau Lake (20'). Over half the stream is considered trout water with the main species being brown trout. Brook and rainbow trout are also present. Fish species found in the stream include northern pike, walleyes, largemouth bass, bluegills, perch, black crappies, pumpkinseeds, green sunfish and a variety of forage fish.

Feeder streams include Black Brook, South Fork Willow River, Ten Mile Creek, Anderson Spring and a small spring feeder stream that flows into the Willow from Section 9, Township 30 North, Range 17 West. Mallards, blue- winged teal, wood ducks and hooded mergansers may be found nesting in the 1,410 acres of predominantly wooded wetlands. Muskrats and beaver are also present.

Public land consists of 0.3 miles of county-owned frontage with 20 road bridges also providing access to the stream. Private development is limited to 20 cottages and homes.

From: Sather, LaVerne M. and Threinen, C.W., 1961. Lake and Stream Classification Project. Surface Water Resources of St. Croix County, Wisconsin Department of Natural Resources, Madison, WI.

Date  1961

Author   Aquatic Biologist

Historical Description

Water quality and fisheries surveys in 1992 indicate that nonpoint source pollution degrades water quality and fish populations in the Willow River. Ammonia and total phosphorus concentrations were significantly increased during high flow conditions. A fisheries study indicated that fish populations lacked a diversity of species.

Monthly grab sampling of Willow River water quality was initiated in July 1990 at four sites from New Richmond to the Little Falls Dam. Two additional ammonia sampling sites were added in November 1990 and February 1991. Grab samples for ammonia were collected at a few locations in the reach in August 1984, October 1984 and August 1988. Continuous recording dissolved oxygen (DO) equipment was deployed at three locations in the reach in August 1988 and in July and August 1991. Equipment failure resulted in the loss of some recording DO data.

Date  1992

Author   Aquatic Biologist

Historical Description

When examining the data, special consideration was given to three important factors affecting water quality:
1. The New Richmond Flowage was drawn down in late June and early July of 1991.
2. The 1988 data was collected during unusually low flow conditions, although still four times above the Q,.,, flow.
3. Known sources of pollutant loading to the river reach being evaluated were the New Richmond WWTP, the Friday Canning spray irrigation site and the past spills of fertilizer to groundwater by Blue Ribbon Feeds in New Richmond.

The water quality standard for DO was not met in the Willow River at all three monitoring locations between Hwy 64 and Boardman in 1988 (Figure 1). The portion of the reach classified as a warmwater fishery did not maintain the minimum DO standard of 5 mg/l, measured at Hwy 64 and at a point 0.75 miles below the WWTP. DO leaving the reach classified trout stream (Boardman site) did not maintain the minimum DO standard of 6 mg4. Monitoring in 1991 found no violations of the DO standard (Figure 2). However, examination of the river DO data expressed as percent saturation indicated that the river had lower DO levels at Hwy 64 and at the downstream site than at the New Richmond Dam. This condition was present to a greater extent in 1988.

Both the 1988 and 1991 data were collected under stable, non-event flow conditions. Based on the gauged flow of other rivers in the region, Willow River flow was estimated to be about 50% higher during the 1991 sampling than the 1988 sampling. The difference between the 1988 and 1991 DO was likely linked to the response of river water quality to different flows or to a change due to the loss of the upstream impoundment. Top draw impoundments can adversely affect downstream DO if they contribute significant BOD, in the form of algae passing over thedam. With the impoundment drawn down, this source of BOD, would be eliminated. The slightly depressed DO below the New Richmond Dam in 1991 may be the result of oxygen demand of sediments scoured out of the former impoundment as a new river channel was being formed. The river experienced higher suspended solids in the summer of 1991, after the impoundment was drawn down, than the previous summer.

Total phosphorus in the Willow River generally fell between 0.05 and 0.15 mgil. The highest values were associated with high river flow in the spring (Figures 5&6). The minimum total phosphorus level was higher at Hwy A (0.07 mgl) than at the other sites (0.04 mgil). Phosphorus loading from the New Richmond WWTP may be the cause. Since substantial increases in river flow occur between the WWTP and Hwy A, the minimum total phosphorus concentration immediately below the WWTP may be substantially higher the minimum documented at Hwy A.

A high concentration of ammonia nitrogen was documented in the Willow River at Hwy 64 in 1984. The concentration was only slightly less than the level toxic to warmwater aquatic life in a chronic exposure. Since no sample was taken in the downstream river section classified as a trout stream, it is unknown if the lower trout stream water quality standard was met in that reach. The river seems to have been on a downward trend in low flow ammonia nitrogen since that sample was taken. No violations of the water quality standard have been documented.

Date  1992

Author   Aquatic Biologist

Historical Description

The possible causes for the high ammonia levels in 1984 include large spills of high nitrogen fertilizer into the groundwater near the New Richmond Dam by Blue Ribbon Feeds in 1981 and 1983 and Friday Canning's spray irrigation field. Groundwater monitoring at the Friday Canning site, which is located on the banks of the river, has shown decreases in pollutant levels since 1985, when loading to the field was reduced. Down gradient monitoring wells still indicate an significant increase in groundwater ammonia nitrogen levels as comparcii to up gradient wells. The sources of ammonia nitrogen in the Willow River near New Richmond can be evaluated by examining Figure 7, which includes only data collected when river ammonia levels were high. On 6/3/91, ammonia levels, as well as suspended solid levels, were elevated entering the reach. This occurred during a time of high flow and was probably the result of nonpoint sources in the watershed above New Richmond Flowage.

On 01/10/91 and again on0 2/05/91 a rise in river ammonia occurred as it flowed past the Friday Canning site. This was during winter low flow conditions, when impacts by ammonia in groundwater on streams would be at the maximum. At this time of year many streams experience a rise in ammonia associated with the onset of cold weather. This may be responsible for the above normal ammonia levels at the New Richmond Dam. The increase in ammonia near the Friday Canning site is in addition to this natural occurrence. On 2/5/91 and again on 3/14/91 a rise in river ammonia occurred between Hwy 64 and Boardman. Loading from the New Richmond WWTP is a possible cause for this rise.

The Willow River was sampled for fecal coliform bacteria at four sites on eight dates during May - October of 1990 and 1991. Of the 29 samples collected, six were above 200 bacteria per 100ml and three were above 400 bacteria per 100ml. The highest bacteria per 100ml at each site were 570 at Odanah Road, 600 at Hwy 64, 3200 at Hwy A and 110 at Little Falls Dam, all recorded on 6/3/91.

Date  1992

Author   Aquatic Biologist

Willow River, Upper Willow River Watershed (SC03) Fish and Aquatic LifeWillow River, Upper Willow River Watershed (SC03) RecreationWillow River, Upper Willow River Watershed (SC03) Fish Consumption

General Condition

This water was assessed during the 2016 listing cycle; total phosphorus and biological sample data clearly met 2016 WisCALM listing thresholds for the Fish and Aquatic Life use.

Date  2015

Author   Wdnr Water Quality

Impaired Waters

The 2018 assessments of the North Fork Willow River (from split with South Fork Willow River, upstream to mouth of Black Brook) showed impairment by phosphorus; new total phosphorus sample data exceeded the 2018 WisCALM listing criteria for the Fish and Aquatic Life use. However, 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, this water was proposed for the impaired waters list.

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 2016 . See also 'monitoring' and 'projects'.



Monitor Invasive Species
Monitor Invasives
Lake Management Plan Development
Stormwater Planning, Implementation
TMDL Implementation
On agricultural lands, conservation tillage, lowering soil test phosphorus, nutrient management to match fertilizer addition to crop need, along with careful manure handling are important agricultural best management practices that will help achieve the non-point source reduction. Improved agricultural management practices are especially recommended for the headwaters reaches and tributaries of both the North and South Forks of the Willow.
Monitor Watershed (Status,Sources,Impairments)
Basic waters inventory monitoring should be conducted on the seven waters so designated in this watershed.
Monitor or Propose 303(d) Listing
Continue monitoring the Willow River, St. Croix County for sediment, phosphorus loading related to an impaired waters listing.
Sewer Service Area Planning
The Hudson Urban Area is located in the southwestern quadrant of St. Croix County which lies in West Central Wisconsin. This rapidly urbanizing area is about 18 miles east of the Cities of Minneapolis and St. Paul, and about 66 miles west of Eau Claire, Wisconsin.
Monitor Targeted Area
Project: Willow River (SC03, SC02) Watershed Planning
Water Quality Planning
Willow River (SC02,SC03) Watershed Planning
ATTAINS Alternative Restoration Approach
Upper Willow River PWS Plan - Nine Key Element Plan - This Upper Willow River priority watershed plan has two parts. The first is a report of technical assessment of water quality problems and associated nonpoint sources contributing to problems and identification of actions needed to minimize water quality problems. The second part is the detailed plan of implementation. It identifies tasks necessary to carry out actions identified in part one; agencies which will carry out needed action tasks; a schedule of implementation; and the type and amount of staff resources needed.
Nine Key Element Plan
Upper Willow River PWS Plan - Nine Key Element Plan - This Upper Willow River priority watershed plan has two parts. The first is a report of technical assessment of water quality problems and associated nonpoint sources contributing to problems and identification of actions needed to minimize water quality problems. The second part is the detailed plan of implementation. It identifies tasks necessary to carry out actions identified in part one; agencies which will carry out needed action tasks; a schedule of implementation; and the type and amount of staff resources needed.
TMDL Development
Lake Mallalieu TMDL Development
Information and Education
Continued efforts are needed to raise awareness of karst geology to protect groundwater and human health.
Information and Education
Expand outreach on habitat improvement and protection, invasive species control, climate change factors and preventive measures, etc.
Information and Education
Develop effective tools for conveying actions that can be taken by private citizens, industries, agriculture, municipalities, commercial and professional groups, etc.
Information and Education
Continue efforts to inform the public on the goal to reduce phosphorus inputs to Lake Mallalieu and Lake St. Croix, thus reducing the inputs into the Willow River, which both lakes feed.
Monitor Fish Community
Continue long-term monitoring of fisheries and habitat to track trends and develop further lake and fisheries management recommendations.
Monitor Watershed (Status,Sources,Impairments)
Critical habitat surveys and reports should be completed on lakes and streams where habitat, native plant beds, and public rights features need to be inventoried and management recommendations developed.
Stormwater Planning, Implementation
Water temperature should be safeguarded to protect trout waters from gradual warming. Infiltrating stormwater to the groundwater for eventual stream recharge is one method. Protecting wetlands for their filtering function is another.
Habitat Restoration - Upland
Working to reduce agricultural land use in dry run streams - or ephemeral streams - would help reduce agricultural related runoff and would also reduce negative changes in the watershed’s natural hydrologic flows.
Wastewater Monitoring or Management
Optimizing removal of phosphorus at point source discharges is also important, particularly from the communities of Clear Lake and New Richmond, as well as at other smaller, surface water discharging communities and industries.
Citizen-Based Stream Monitoring
All resource agency staff, recreational users and the public need to remain vigilant to prevent the spread of both aquatic and terrestrial invasive species.
Dam Safety or Removal
The Department should give consideration when the New Richmond Dam is rebuilt to installing a structure capable of both top and bottom draw. This flexibility may be useful in correcting the dissolved oxygen problems observed at Hwy 64 by reducing the amount of algae delivered to the stream. Without correction of the river oxygen problem, future expansion of the New Richmond WWTP may be more difficult and costly (Type B).
Wastewater Monitoring or Management
A wasteload assimilation study under summer low flow conditions should be conducted by DNR WRM in the vicinity of the New Richmond WWTP in anticipation of WWTP expansion to accommodate growth in the region. The potential for impact extending into the downstream trout fishery and overlap with the sanitary district discharge at Boardman should be addressed (Type B).

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

Willow River is located in the Upper Willow River watershed which is 183.67 mi². Land use in the watershed is primarily agricultural (50.40%), grassland (24.60%) and a mix of forest (17.40%) and other uses (7.60%). This watershed has 319.19 stream miles, 516.82 lake acres and 5,595.44 wetland acres.

Nonpoint Source Characteristics

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

North Fork Willow River is considered a Cool-Cold 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.

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.

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