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Wetland Monitoring

Prior to European settlement, wetland basins covered 4 to 6 million acres, or approximately 11% of Iowa's surface area. Wetlands were part of every watershed in the state, but nearly 95% of them have been drained for agriculture. Congress gave large incentives to drain and develop the land as quickly as possible, resulting in the loss of wildlife habitat, damage to water quality, rapid topsoil erosion, and increased incidents and severity of flooding. Instead of adapting to the landscape, the landscape was forever changed by the needs of the settlers. Ecologically, Iowa is now considered to be one of the most altered states in the nation.

Today, there is a greater scientific understanding of the importance of the role wetlands play in water quality, flood mitigation, nutrient reduction, habitat for fish and wildlife, and how our landscape functions as a whole. Conservation efforts to restore wetlands have often been successful. When allowed to hold water again, the original wetland basins has shown a remarkable resilience, returning to their natural state rapidly and once again performing their key ecological functions. The current focus of current and future wetland work in Iowa is restoring 'priority' wetlands. Since over 90% of the land in Iowa is privately owned, it is up to natural resource agencies, conservation organizations, and agricultural groups to work with Iowa's landowners to consider voluntary efforts to restore wetlands on their land.

In 2005, the Iowa Department of Natural Resources’ (IDNR) Watershed Monitoring and Assessment Section began its wetland monitoring program in north-central Iowa, through grant funds provided by the U.S. Environmental Protection Agency. A statewide monitoring program was developed to assess these valuable areas, and results from this monitoring will enable the IDNR to determine the ecological condition of wetlands while documenting the leading contaminants and stressors found in these systems. This information will help make informed decisions affecting the future of Iowa’s wetlands.

Wetland Monitoring Strategy

The overall Iowa DNR strategy is to develop a comprehensive statewide wetland monitoring program that can address all of the inherent variables associated with different types of wetlands, an extremely altered landscape, and cyclic patterns of wet/dry conditions in order to guide management decisions regarding Iowa’s wetland resources. This strategy will provide a framework for an ongoing assessment of Iowa’s wetland resources and the level of success achieved by our management programs.

Iowa DNR wetland monitoring protocols:

Wetlands Types

The term ‘wetland’ is often used interchangeably with other terms such as ‘marsh,’ ‘swamp,’ ‘slough,’ ‘pond,’ ‘pothole,’ ‘fen,’ or ‘bog.’ It is important to understand that there are several different types of wetlands. Often these wetland terms can be confusing. For the purposes of using a consistent name for them in this website, the term ‘wetlands’ is used to represent the collective group of all wetland types found in Iowa.

Benefits of Wetlands

Iowa enjoys a diverse range of wetlands, and they still occur throughout the state. The ability of wetlands to absorb large quantities of water and release it slowly allows them to accomplish several crucial tasks.
  • Flood Mitigation: Wetlands help moderate the speed and quantity of water during precipitation events through its capacity to store and release excess water, without which more intensive flooding would occur. Where appropriate, wetlands are a cost-effective alternative to expensive dams, levees, and other man-made controls.
  • Water Quality Treatment: Like the kidneys of the human body, wetlands function as filters for the aquatic ecosystem. Wetlands store incoming surface runoff, and the slow release allows many biological, geological, and chemical processes to occur- breaking down pollutants, using excess nutrients (such as nitrogen fertilizers) to be "burned up" in aquatic vegetation growth, and the reduction of bacteria through biologic intake.
  • Wildlife: Wetlands provide year-round critical habitat for many types of wildlife, even during the harshest winter season. Acre for acre, wetlands are perhaps the most dynamic areas Iowa has ecologically, supporting waterfowl, upland wildlife, migratory bird species, shorebirds, furbearers, amphibians, and fish. This wildlife diversity helps to keep invasive and pest species in check; pests such as mosquitoes provide a food source for many birds, frogs, and dragonflies.
  • Carbon Storage: Like forests and prairies, the wetland plant community stores excess carbon emissions via plant absorption. The root system will uptake carbon for plant material, and photosynthesis will remove of carbon dioxide from the air.
  • Intrinsic Value: At a basic level, wetlands are valuable to the public just being wetlands. They provide recreational opportunities, aesthetic enhancement, and are part of Iowa's natural heritage.

Current Threats to Wetlands

Despite the enormous benefits of wetlands and the recently increased public awareness of their essential role in the landscape, wetlands in Iowa still face many obstacles. National farm policy dictates that USDA simultaneously provides incentives for both wetland conservation and intensive row cropping. Urban sprawl can lead to wetland disruption as well- even developers who recognize the importance of wetlands may fear leaving them intact will lead to problems such as pest species.

  • Drainage: Although most of the drainage done through tiling, ditching, and stream channelization took place in the past, it is still an ongoing threat to existing wetlands. Even drainage of areas surrounding wetlands can affect their hydrology, disconnecting them from other water bodies or altering water tables.
  • Ponding: The opposite of drainage, some wetlands are turned into ponds for recreation, livestock watering, or other perceived benefits. Ponding also results when other landscape changes cause a wetland to hold more water than it would naturally, which alters the bio-geo-chemical processes that occur within it and can greatly reduce its effectiveness. Higher water levels also support larger populations of rough fish (primarily carp and bullhead), disrupting the food chain, causing greater turbidity, and further reducing the quality of the wetland.
  • Land Practices: Many sloughs are connected to streams and rivers. Some land practices in those streams' watersheds result in increased run-off of sediment, herbicides, pesticides, and fertilizers. These chemicals can damage ecological systems within the wetland, reducing effectiveness by destroying aquatic diversity. Siltation from run-off reduces the life expectancy, filling it in until it no longer functions as a wetland.


There are several important wetland wildlife habitat conservation initiatives that affect Iowa's wetland conservation work. Without these initiatives, fewer wetland acres would have been restored, and there would likely be less wetland acres overall. More information can be found below:

Non-governmental Organizations (NGOs) also do a tremendous amount of work related to Iowa’s wetlands. Organizations such as Ducks Unlimited, Pheasants Forever, The Nature Conservancy, Iowa Natural Heritage Foundation, Waterfowl Association of Iowa, The Izaak Walton League of America, and others all play a major role in wetlands conservation. In fact, these groups have helped protect, restore, and enhance several wetland areas over the years that may have been lost had it not been for their ability to act quickly and efficiently. Despite each organization having its own unique goals and objectives, they all agree on the importance of viable wetland resources and recognize the importance of partnering with each other as well as federal, state, and county natural resource agencies to leverage valuable dollars for wetlands protection and restoration.


Laws of the United States and the State of Iowa have assigned the US Army Corps of Engineers (Corps) and the Iowa Department of Natural Resources (IDNR) with specific and different regulatory roles designed to protect the waters within and on the State's boundaries. IDNR's Wetlands Permitting handles Section 401 certification.


Learn more about wetland-specific educational opportunites by visiting the Iowa Conservation Education Coalition and the IDNR's Education sites.


The following section is a compilation of links to information and research related to wetlands.