© John Jacob, TCWP

What are Prior Converted Wetlands?

In general, prior converted wetlands are historic wetland areas that were modified for a different use, usually for agriculture or development. More technical definitions are used by Federal programs which target prior converted wetlands for restoration.

History Pre-Clean Water Act

Wetlands were once viewed as wastelands. A source of mosquito-borne diseases, difficult to travel and hard for early farmers to cultivate for food and fiber–wetlands were generally viewed as obstacles to survival and development. As a result, draining and repurposing wetlands was encouraged. Drained wetlands were often extremely fertile and many were converted to agricultural uses.

Even in the 1960s, the US government was still encouraging wetland drainage for flood prevention. Public works projects incentivized draining wetlands and many USDA policies encouraged cost-share drainage programs for agriculture. The EPA estimates that 100 million acres of wetlands were lost in the United States since the late 1700s.

History Post-Clean Water Act

However, in the 1970’s public awareness of the valuable services provided by wetlands grew. The Federal government began to reverse many of its wetland drainage policies. The first major Federal act to protect wetlands was the 1972 Federal Water Pollution Control Act, also known as the Clean Water Act (CWA). Section 404 of the Act established this major federal program to regulate wetlands. Amendments passed in 1977 expanded and improved Section 404 to include agricultural exemption categories, delegation of the 404 program to states, and Federal enforcement powers.

To address the gap in wetland protection by agricultural exemptions, the 1985 Farm Bill included the Swampbuster provision and the Conservation Reserve Program (CRP) provision. The Swampbuster provision discouraged drainage of wetlands for agricultural commodities by denying USDA program benefits to farmers that further drained wetlands under certain conditions. At the same time, the CRP program encouraged farmers to remove highly erodible and other sensitive lands (including wetlands) from production for 10 years in exchange for a rental payment. It also provided funds to restore previously cropped wetlands, floodplains, and riparian areas.

Because of the growing awareness and Federal support for conservation of wetlands, wetland conversion has declined. According to the National Status and Trends Report conducted by the US Fish and Wildlife Service, between 1950s and 1970s nearly 500,000 acres of wetlands were lost per year. More recently, between 2004 and 2009, this number has declined to a loss of 13,800 acres of wetlands per year.

Learn More

U.S. Geological Survey (USGS) History of Wetlands
USDA’s Farmable Wetlands Program
TCWP’s Sheldon Lake Prairie Wetland Restoration from Prior Converted Wetlands Webpage