Shelter from the Storm

In the summer of 1993, residents of the American Midwest experienced the most costly flood in the history of the United States.1 By the end of that summer, the Mississippi River in St. Louis was 20 feet above flood stage, and levee breaks in Illinois led to the inundation of thousands of acres of land. The flood claimed 48 lives and caused nearly $20 billion in damage.


PennEnvironment Research & Policy Center

Wetlands are more than just scenic parts of America’s natural landscape. They are also home to wildlife and perform many vital functions that protect the health of our waterways and communities. By trapping sediment and filtering excess nutrients and pollutants out of the water that flows through them, wetlands support water quality. 

Of crucial importance for our towns and cities, wetlands also offer flood protection by absorbing large amounts of water that may fall during a storm before releasing it slowly into the environment. An acre of wetland one foot deep can hold approximately 330,000 gallons of water. This can reduce flood peaks and slow water flow. Even isolated wetlands can help by reducing storm water runoff that might contribute to local flooding. All told, the nation’s inland wetlands provide over $237 billion worth of water flow regulation annually.

The Clean Water Act is the nation’s most important tool for safeguarding wetlands – protecting our communities from flooding and preserving the quality of our water. Since its enactment, the Clean Water Act has succeeded in reducing the rate of wetlands loss nationwide. In fact, the rate of wetlands loss slowed after the law was passed and wetland acreage increased modestly between 1998 and 2004. However, a recently exposed loophole in the law has cast doubt over the Clean Water Act’s reach and puts millions of acres of wetlands at risk of destruction. The Environmental Protection Agency (EPA) has proposed a rule that would close this loophole – a step that would be the biggest victory for clean water in more than a decade.

This report describes the importance of wetlands as protection against flooding in 15 states. To protect wetlands in those states and across America, the EPA must finalize its proposed Clean Water Act rule this year.