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Chris Jennings pintails potholes.jpg

By Scott Yaich, Ph.D.

Boiled down to the simplest recipe, two basic ingredients are necessary for the Prairie Pothole Region to produce ducks: grass and water. Biologists have long known that the "Duck Factory" can raise ducks in proportion to the amount of grass and water-filled wetlands on the landscape. And every spring, duck hunters anxiously watch for news of wetland conditions on the prairies as their first indication of what the next hunting season might bring.

Unfortunately, after 30 years of protection by the federal Clean Water Act (CWA), prairie potholes and other wetlands of vital importance to ducks have been put at significant risk by U.S. Supreme Court decisions in 2001 and 2006. These decisions concerned what constitutes the "waters of the United States," and therefore which wetlands the federal government has jurisdiction to regulate. The net effect of these cases was that CWA protection for tens of millions of acres of wetlands was weakened or withdrawn. Wetlands most important to waterfowl, including prairie potholes, playa lakes, and rainwater basins, are among those at greatest risk.

The question of exactly which wetlands and other waters remain protected by the CWA has been unclear ever since the 2001 Supreme Court decision was issued. And it's widely agreed that new federal legislation will be required to resolve the confusion and protect these important waterfowl habitats. Federal legislation to restore former wetland protections afforded by the CWA has been introduced several times, and the most recent bill has advanced further in Congress than any other to date, but its chances of passage now appear slim in this Congress.

Ironically, the seeds of the confusion and risk to wetlands and waterfowl were planted when Congress defined "navigable waters" as "waters of the United States" in the original CWA of 1972. Unfortunately, the court's recent decisions have only magnified misunderstandings about what Congress intended to protect with this legislation. Many people, including many policymakers, have been erroneously led to believe that the CWA applies only to navigable waters—in the context of being "boatable"—and doesn't necessarily apply to all wetlands. In reality, Congress intended to broadly protect the nation's wetlands and waters because they recognized that protecting navigable streams and rivers from pollution and other degradation requires tributaries and wetlands in their watersheds to be protected as well.

While many wetlands like prairie potholes may not have a surface connection to rivers or streams, these waters are connected in many other ways. These connections are the key to understanding the intended definition of "waters of the United States," which includes not only navigable waters but also wetlands and other water bodies that are linked via shared water resources. For example, prairie potholes are clearly connected to rivers like the Missouri when they spill over into small streams and other tributaries. But more often, prairie potholes and other geographically isolated wetlands are linked to rivers through the water table, which forms a continuous subsurface connection among a variety of water bodies. Thus, to protect rivers, you also have to protect all the wetlands that share the same groundwater supplies.

This is well known in the arid West. In Colorado, for example, private landowners along the South Platte River who manage wetlands in partnership with Ducks Unlimited receive compensation for the clearly documented role these wetlands play in recharging groundwater supplies that sustain river flows. On the southern Great Plains, the Ogallala aquifer is a vital water source for agriculture, homes, and communities in eight states. At low elevations, the aquifer discharges water directly into navigable rivers such as the Platte and Arkansas. At higher elevations, the aquifer is recharged from the surface by sandhill wetlands and rainwater basins in Nebraska and playa lakes in Texas, forming a direct connection between the region's wetlands and rivers. But if these wetlands are not considered part of the "waters of the United States" and therefore are not protected by the CWA, the navigable rivers they sustain with groundwater will be vulnerable to pollution and other degradation.

Migratory waterfowl provide another ecological link between wetlands and other waters. Waterfowl hunting and viewing are clearly forms of interstate commerce, which is among the primary legal foundations of federal authority under the CWA. Arkansas's duck hunting economy, for example, measures in the hundreds of millions of dollars and depends heavily on ducks raised on geographically isolated wetlands—particularly prairie potholes—in other states. If wetlands in the Dakotas are drained because of the confusion and weakening of the CWA, interstate commerce, including the waterfowl-based economy of Arkansas, will suffer as a direct result.

As the legal wrangling over the definition of the "waters of the United States" continues, we must all help our elected officials and policymakers understand that science and common sense must prevail. Wetlands such as prairie potholes clearly have significant connections to navigable rivers and other waters. CWA protections must be restored to wetlands not only because of the important value they have for fish and wildlife but also as a matter of public health and safety. To reduce flooding, provide ample water supplies, and support healthy populations of waterfowl and other wildlife, Congress must pass legislation that recognizes the true connections among wetlands and navigable waters.

Migratory birds and their habitats, and what they mean to us, are among the many important things that link DU members to the hundreds of millions of U.S. citizens who share and depend on our nation's water resources. As this issue progresses, DU will be working with our partners in agriculture and our broader membership to formulate supportive wetland policies.


The migratory nature of ducks and geese is the basis of federal authority over waterfowl hunting and cooperative management of the birds among states, provinces, and countries. Waterfowl are a resource shared by all North Americans. A few statistics illustrate the extent of the connections shared by waterfowl, their habitats, and hunters across political boundaries:

  • More than 55 percent of banded waterfowl in the harvest are bagged outside the state or province in which they were banded.
  • Of the waterfowl raised in the Dakotas and Montana that are harvested, 70 percent are bagged outside of these states, including almost 10 percent that are bagged outside the United States.
  • Of the 76,576 state duck stamps purchased in Arkansas in 2009, 28,935 were bought by nonresidents.


In much of Canada's Prairie Pothole Region, wetland loss is the greatest limiting factor to waterfowl production. As many areas of Prairie Canada have already lost more than 70 percent of their original wetlands, restoring and protecting these key waterfowl habitats is a top priority of Ducks Unlimited Canada (DUC). But the use of massive earth-moving equipment is making it easier than ever for prairie landowners to drain and fill wetlands. A dramatic example occurred in north-central Saskatchewan in 2008. After two wet years, several landowners joined forces and hired a professional contractor to drain wetlands on their properties. In only five months' time, more than 700 duck-producing wetlands were drained. In response to such losses, DUC is working with provincial governments to develop and implement more protective wetland policies to complement its on-the-ground conservation projects.

This story is a cautionary tale for us in the United States. Wetland drainage on the prairies of the United States could easily dwarf that of Canada if Clean Water Act protections are not restored soon.