Green Bay (Inner Bay, Aoc), Duck Creek,East River,Suamico and Little Suamico Rivers Watershed (GB01)
Green Bay (Inner Bay, Aoc), Duck Creek,East River,Suamico and Little Suamico Rivers Watershed (GB01)
Green Bay (Inner Bay, Aoc) (70)
13867.36 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.
This bay/harbor is impaired
Low DO, Degraded Habitat, PCBs Contaminated Fish Tissue, PCB Contaminated Sediments
Total Phosphorus, Sediment/Total Suspended Solids, PCBs
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.
Streams capable of supporting a warm waterdependent sport fishery. Representative aquatic life communities associated with these waters generally require cool or warm temperatures and concentrations of dissolved oxygen that do not drop below 5 mg/L.
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.
Streams capable of supporting a warm waterdependent sport fishery. Representative aquatic life communities associated with these waters generally require cool or warm temperatures and concentrations of dissolved oxygen that do not drop below 5 mg/L.
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.


Green Bay is by far the most important surface water resource in Brown County in terms of recreational potential. The bay served as a natural starting point for early settlement and transportation to the interior of Wisconsin via the Fox River. The Fox River is also very important as a determinant of the water quality in lower Green Bay. The bottom materials of the lower bay consist of a very loose, flocculent sediment. As a result the water clarity changes significantly over short periods of time due to the ease with which these materials become resuspended in the water. Chemically Green Bay is a hard water alkaline basin which has a total alkalinity of 143 mg/l. Green Bay receives a large nutrient load from industrial, municipal, and agricultural sources.

Date  2011

Author   Aquatic Biologist

Historical Description

Nutrient levels consistently exceed 0.1 mg per liter of nitrogen and .02 mg per liter of phosphorus, enough to create bloom conditions. Heavy algae blooms are common and have caused oxygen depletion in some sections of the bay creating isolated fish kills during the summer months. In addition, the Bay has been used as a dumping grounds compounding the problem. Green bay is heavily developed with permanent and seasonal dwellings along the southeast shore and in scattered sections on the west shore. Extensive wetlands in the southwest corner limit development and provide habitat for waterfowl and wildlife. This habitat is rapidly being diminished through the steady encroachment of man-deposited fill into the marsh. The fishery of Green Bay has changed drastically in the past three decades. Once a fishery of carp, northern pike, drum, suckers, white bass, bullheads, catfish, and an abundant of perch was present.

Today conditions in the area of Brown County have gotten so bad that only carp dominate the scene for in shore waters. Even the perch, which is noted for being able to tolerate very poor water quality, has been eliminated as a permanent feature of the fishery and furnishes a seasonal sport fishery near the mouths of oxygen bearing streams. The commercial fishery which formerly harvested mostly perch, whitefish, and some lake trout has now moved out of southern Green Bay in search of these fish species. The commercial catch for all of Green Bay has vacillated, declining from 15,768,000 pounds (61.7 percent of the total Lake Michigan catch) in 1949 to 6,636,000 pounds (31.6 percent of the total Lake Michigan catch) in 1963. In 1971 the yield jumped to 17,242,000 pounds primarily as a result of increased alewife harvest. Alewife now dominates the commercial catch. For additional fishery information see the Fox River narrative. In the more stable years of the fishery yields to the commercial fishery for the Bay as a whole ranged between 10.4 and 19.6 pounds per acre.

Public access is available from several road endings, public hunting grounds, public access sites with boat ramps, and navigable water from the Suamico and Fox Rivers, and Duck Creek. There are also parks and waysides providing walk-in access. A 26 foot deep navigation channel 300-500 feet wide cuts through the south end of the bay and affords access of large ships to the city of Green Bay. Source: 1972, Surface Water Resources of Brown County Green Bay, T24, 25N, R21, 22E, Sections-many Area = approx. 49,000 acres in Brown Co., Depth =26 ft

Date  1972

Author   Surface Water Inventory Of Wisconsin

Green Bay (Inner Bay, Aoc), Duck Creek,East River,Suamico and Little Suamico Rivers Watershed (GB01) Fish and Aquatic LifeGreen Bay (Inner Bay, Aoc), Duck Creek,East River,Suamico and Little Suamico Rivers Watershed (GB01) RecreationGreen Bay (Inner Bay, Aoc), Duck Creek,East River,Suamico and Little Suamico Rivers Watershed (GB01) Fish Consumption


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.


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

Green Bay is located in the Suamico and Little Suamico Rivers watershed which is 171.78 mi². Land use in the watershed is primarily agricultural (41.10%), wetland (20.10%) and a mix of forest (15.70%) and other uses (23.20%). This watershed has 340.92 stream miles, 10,769.31 lake acres and 15,918.95 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.This water is ranked High Lake for individual BayHarbors based on runoff problems and the likelihood of success from project implementation.

Natural Community

Green Bay (Inner Bay, Aoc)'s natural community is not yet identified 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.

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