Wetlands Improve Water Quality
Healthy wetlands slow down and filter runoff from storms and snowmelt, allowing sediment and other pollutants to settle out before reaching our lakes, rivers, streams, and drinking water aquifers. Wetlands also have the ability to absorb and transform or metabolize nutrients and contaminants. Preserving these water purification functions of wetlands can save your community money by eliminating or reducing the need for costly upgrades to your community’s water management systems. Because water quality improves as wetland acreage increases in the watershed1 and property values increase as water quality improves2, preserving wetlands can help increase your community’s tax base.
"Our local wetlands, surrounding Ashland and the Chequamegon Bay, the Kakagon Sloughs and Fish Creek Estuary, are vital in preserving the high water quality and healthy eco-system for Ashland and its residents. We must be constantly aware of their fragile state and protect them from harm, for the good of us all."
~ Mayor Ed Monroe, City of Ashland

The Halfway Creek Marsh, near La Crosse, retains 1.8 million cubic yards of sediment and helps purify water before it enters the Mississippi River.

Did You Know?

  • Communities in the Charles River Basin (Massachusetts) avoid spending ~ $25 million annually on stormwater, runoff, and wastewater management infrastructure because of the pollutants and sediment naturally removed and filtered by 8,500 acres of wetlands.
  • 100,000 acres of wetlands save communities in the Lower Fraser Valley (British Columbia, Canada) between $18 to $50 million annually by removing phosphorous and nitrogen that would otherwise have to be removed by constructed stormwater, runoff, and wastewater management facilities.
  • New York City avoided spending $3-8 billion on the construction of new wastewater treatment plants by investing $1.5 billion in acquiring wetlands around existing drinking water reservoirs.
  • The cypress swamps of Florida remove 98% of nitrogen and 97% of phosphorous entering the wetlands from stormwater, wastewater and other runoff.

Note: These quick facts have been compiled from the resources listed below.

Additional Resources on How Wetlands Improve Water Quality

  1. The Values of Wetlands: Importance of Scale and Landscape Setting. Mitsch, W. and J. Gosselink. 2000. Ecological Economics. 35(200): (See pages 25-33).
  2. Lakeshore Property Values and Water Quality: Evidence from Property Sales in the Mississippi Headwaters Region. Mississippi Headwaters Board and Bemidji State University (2003).
  3. Improved Water Quality -- Wetland Habitat Values, Ducks Unlimited (2009).
  4. Natural Values -- The Importance of Wetlands and Upland Conservation Practices in Watershed Management: Functions and Values for Water Quality and Quantity, Ducks Unlimited Canada (2004). (See Pages 13-28).
  5. Direct and Indirect Impacts of Urbanization on Wetland Quality, Center for Watershed Protection (2006). (See pages 6-7).


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