Wisconsin’s Freshwater Estuary Initiative
is a statewide effort to increase awareness and promote stewardship of Wisconsin’s freshwater estuaries. Freshwater estuaries are extremely important to the natural and economic health of the state and are central to many Wisconsin communities.
A Place We Call Home
Many of our earliest communities, such as Green Bay, Milwaukee, and Superior, developed adjacent to Wisconsin’s most prominent river systems because of their importance as navigation routes. Those same rivers often support freshwater estuary systems where they empty into the Great Lakes. Even though community members may not use the term “freshwater estuary” to describe them, communities identify with these systems in significant ways. Whether it’s Kewaunee, Algoma, Milwaukee, Superior, Ashland, Green Bay, or Sheboygan, freshwater estuaries are locally important for activities such as hunting, fishing, boating, and economic development. These freshwater estuaries truly are a historic and vital component of their surrounding communities.
A freshwater estuary is a unique Great Lakes coastal landform that occurs where river and Great Lakes water mix in shallow wetland areas near the mouth of a river. Many of our communities, such as Green Bay, Milwaukee, and Superior, developed adjacent to Wisconsin’s prominent river systems because of their importance as navigation routes and sources of water. Those same rivers often support freshwater estuary systems where they empty into the Great Lakes. Approximately 37% of Wisconsin’s population resides in coastal counties (University of Wisconsin-Sea Grant, 2001) in relatively close proximity to the Great Lakes and the freshwater estuary systems they support.
Even though community members may not use the term “freshwater estuary” to describe them, communities identify with these systems in significant ways. Freshwater estuaries and their associated coastal wetlands are locally important for activities such as hunting, fishing, boating, and economic development. For example, a study of coastal marshes on Saginaw Bay in Michigan found that residents were willing to pay $3,596 per acre for voluntary protection of coastal wetlands over their lifetime. Residents also rated the annual recreational use value of the marshes at 15.9 million dollars (Whitehead, Groothuis, Southwick, & Foster-Turley, 2006). Another study by Woodward & Wui (as cited in Whitehead et al., 2006) conducted a meta-analysis, or systematic review, of the available research regarding the economic values of freshwater wetlands. Based upon their analysis, freshwater wetlands have an estimated value of approximately $540 per acre for recreational fishing, $1,176 per acre for commercial fishing, $106 per acre for bird hunting, and $1,832 per acre for bird watching (based upon 2005 dollar values).
Freshwater estuaries are important components of their surrounding communities and provide economic benefits for Wisconsin’s citizens.
A Home for Many Other Things as Well
It’s no surprise that freshwater estuaries are often the destination of hunters and anglers. Freshwater estuaries are both the nursery and kitchen for diverse populations of fish, wildlife, and waterfowl that rely on them for shelter, food, and spawning areas.
The diversity of habitats, water depths, sediment types, and other natural features found in freshwater estuaries make them important for many wildlife species. Great Lakes coastal wetlands, like those associated with freshwater estuary systems, have long been recognized as places of increased biodiversity and abundant wildlife (Maynard & Wilcox, 1997).
Freshwater estuaries are critically important for many species of birds. A literature review of waterfowl use of the Great Lakes conducted by Prince, Padding, & Knapton (1992) determined that coastal wetlands regularly provide breeding, migratory, and wintering habitat for 24 species of waterfowl. The literature review also found that coastal wetlands with a high interspersion of different habitats, such as the emergent marsh, submergent marsh, and open water habitats 
frequently found in freshwater estuaries, are especially important for waterfowl use. The Great Lakes also serve as a corridor for migratory passerines (sometimes referred to as “songbirds”) and shorebirds. The coastal wetlands of freshwater estuaries offer critical food and shelter for these migrating birds (Epstein, Spencer, & Feldkirchner, 2002).
The fisheries of the Great Lakes and its connected river systems are also closely linked to freshwater estuaries. The coastal wetlands associated with freshwater estuaries provide important nursery and refuge areas for a variety of fish species (Maynard & Wilcox, 1997; Simon & Stewart, 2006). For example, over 90 percent of the approximately 2000 species of fish in the Great Lakes are directly dependent on coastal wetlands for some part of their life cycle (Whillans, 1987). The Wisconsin Department of Natural Resources (2006) states that the Fish Creek freshwater estuary complex serves as a nursery area for nearly every variety of fish found in Lake Superior’s Chequamegon Bay. They also indicate that the Fish Creek freshwater estuary and its associated tributaries account for 20 percent of the state's self-sustaining migratory fisheries.
Recreational and commercial fishing are significant aspects of Wisconsin’s economy and the quality of life for Great Lakes residents. Sportfishing on the Great Lakes contributed approximately $384 million to the state’s economy in 2001 (American Sportfishing Association, 2002), and Wisconsin’s Great Lakes commercial fishing business produced a catch worth approximately $3.1 million in 2005 (U.S. Geological Survey, 2005). Freshwater estuaries and their associated wetlands are important to maintaining Great Lakes fisheries and the recreational and economic opportunities they provide.
Nature’s Water Treatment System
Freshwater estuaries are important for cleansing water on its way to the Great Lakes. Water running off the landscape, especially a developed landscape, can carry potential pollutants such as sediments, nutrients, and chemicals directly into rivers. Rivers are able to transport those pollutants, sometimes quite quickly, to the Great Lakes. When the river water reaches a freshwater estuary’s wetlands, however, nature’s filters go to work. Wetland vegetation and aquatic microbes can remove sediment and nutrients from the water column and transform and remove contaminants before they reach the Great Lakes (Maynard and Wilcox, 1997).
The coastal wetlands in a freshwater estuary can function as flood storage, sediment traps, and water quality filters (Maynard and Wilcox, 1997). For example, the Kewaunee River freshwater estuary wetland complex in Northeast Wisconsin traps 20% of the annual river sediment load before it reaches Lake Michigan (Mackenzie, 2001). Studies in Ohio have found that the Old Woman Creek freshwater estuary functions to decrease the annual load of phosphorus reaching Lake Erie (Krieger, 2003). Woodward & Wui (as cited in Whitehead et al., 2006) found that freshwater wetlands have an approximate value of $594 per acre for flood control and $630 per acre for protecting water quality (based upon 2005 dollar values).
Reference
American Sportfishing Association. (2002). Sportfishing in America: Values of our traditional pastime. Alexandria, VA: Author.
Epstein, E., Spencer, E. & Feldkirchner, D. (2002). A Data Compilation and Assessment of Coastal Wetlands of Wisconsin’s Great Lakes. (Wisconsin Department of Natural Resources Publication No. PUBL ER-803 2002). Madison, WI: Wisconsin Department of Natural Resources.
Krieger, K.A. (2003). Effectiveness of a coastal wetland in reducing pollution of a Laurentian Great Lake: hydrology, sediment, and nutrients. Wetlands, 23, 778-791
MacKenzie, R.A. (2001). Great Lakes coastal wetlands-estuarine systems: Invertebrate communities, particle dynamics, and biogeochemical cycles. Unpublished doctoral dissertation, University of Milwaukee, Milwaukee, WI.
Maynard, L. & Wilcox, D. (1997). Coastal wetlands. Background paper, State of the Lakes Ecosystem Conference 1996. (U.S. Environmental Protection Agency Publication No. 905-R-97-015b). Washington, D.C.: U.S. Environmental Protection Agency.
Prince, H.H., Padding, P.I., & Knapton, R.W. (1992). Waterfowl use of the Laurentian Great Lakes. Journal of Great Lakes Research, 18, 673-699.
Simon, T.P. & Stewart, P.M. (2006). Introduction: Coastal wetlands of the Laurentian Great Lakes and the development of indicators of condition. In T.P. Simon and P.M. Stewart (Eds.). Coastal Wetlands of the Laurentian Great Lakes: Health, Habitat, and Indicators (pp. 3-16). Bloomington, IN: AuthorHouse.
University of Wisconsin-Sea Grant. (2001). Wisconsin Coastal Fact Sheet, Population Change: 1990-2000. Madison, WI: Author. Retrieved August 1, 2007, from University of Wisconsin-Sea Grant, Wisconsin Coastal GIS Applications Project web site: http://coastal.lic.wisc.edu/wipop2000.htm
U.S. Geological Survey. (2005). Commercial fishing report. Retrieved August 8, 2007, from Great Lakes Science Center web site: http://www.glsc.usgs.gov/main.php?content=products_data_fishingreports&title=Data0&menu=products
Whillans, T.H. (1987). Wetlands and aquatic resources. In M.C. Healey and R.R. Wallace (Eds.). Canadian Aquatic Resources (pp. 321-356). Ottawa: Department of Fisheries and Oceans.
Whitehead, J.C., Groothius, P.A., Southwick, R., & Foster-Turley, P. (2006). Economic values of Saginaw Bay coastal marshes with a focus on recreational values. Fernandina Beach, FL: Southwick Associates, Inc.
Wisconsin Department of Natural Resources. (2006). Watersheds of the Superior Basin, Fish Creek Watershed Report. Retrieved August 6, 2007, from http://dnr.wi.gov/org/gmu/superior/BasinPlan/watersheds/ls08.html