During early U.S. history, wetlands were considered to be an obstruction to development.  An estimated 117 million acres of wetlands were lost by the 1980s in the United States.  Wetlands were converted to farmland by draining the wetlands, as

permanent settlement began in Colonial America.  They were regarded as swampy lands that bred diseases, restricted travel, and contained abundant natural resources for settlers to use without limit during the 1700s.  As settlers moved west, an even larger scale conversion of wetlands to farmlands started to have a real effect on the distribution and abundance of wetlands in the United States.  After the war, during the 1800s, the Nation's attention focused on westward expansion and settlement. 

Railroads were important in the initial development of transportation routes. Railroads not only opened new lands, including wetlands, to development, but the railroad industry also was a direct consumer of wetland forest products.  In the 1860's, more than 30,000 miles of railroad track existed in the United States (Stover, 1961). The railroads of Ohio consumed 1 million cords of wood annually just for fuel (Gordon, 1969). 

Improvements in drainage technology greatly affected wetland losses in the East and the Midwest. As the use of steam power expanded, replacing hand labor for digging ditches and manufacturing drainage tiles, the production and installation of drainage tiles increased rapidly. By 1880, 1,140 factories located mainly in Illinois, Indiana, and Ohio manufactured drainage tiles that were used to drain wetlands for farming (Pavelis, 1987). By 1882, more than 30,000 miles of tile drains were operating in Indiana alone. 

As technology continued to advance during the 20th century, wetland modification continued at a rapid rate.  Lake and dam structures were being built to create permanent navigable waterways.  Farming also was continuing to grow across the U.S. during this time. Mechanized farm tractors had replaced horses and mules for farm labor during this half century. The tractors could be used more effectively than animals for drainage operations, and the old pasture land then became available for improvement and production of additional crops. In the Midwest and the Northcentral States, the use of tractors probably 

contributed to the loss of millions of acres of small wetlands and prairie potholes.

In 1934, Congress passed the Migratory Bird Hunting Stamp Act, which was one of the first legislative laws to initiate the process of acquiring and restoring America’s wetlands.  Priorities regarding wetlands began to change, especially around the 1950s.  The Federal Government began creating more rules and regulations to help protect wetlands.  More awareness about the benefits and values of wetlands has dramatically increased, especially since the 1970s.  Wetland wildlife refuges were created to help protect wetland habitats.  Many people have since joined together to help restore wetland systems across the U.S., with many areas still expanding. With modern irrigation practices, it is a difficult problem to combat. 

In California during the 1990s, manipulation of water levels in wetlands rather than the complete removal of water as in the past, is a trend that affects wetlands. Partial drainage or lowering of the water levels to allow for certain uses became prevalent in some parts of the country.  Effects of this type of management are uncertain.