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September’s Floods Point to Need for Wetlands

It began life as Tropical Depression Nine, a low-pressure system rotating away from the west coast of Africa. By the end, Hurricane Ike devastated the Texas coast and, along with its two brothers, Lowell and Gustav, dumped 13 inches of rain in parts of the Chicago region between September 13 and 14.

In Illinois, the Metropolitan Water Reclamation District opened gates and locks at Wilmette Harbor, the mouth of the Chicago River, and the Calumet River, allowing stormwater overflow to discharge into Lake Michigan. North and west of Chicago, the swollen DuPage, Fox, and Des Plaines Rivers all reached flood stage, shutting down roads and flooding homes. Rain pounded Indiana Dunes National Lakeshore, and water pouring from the Little Calumet River into Burns Ditch battered marinas. At Ogden Dunes in northwest Indiana, fast moving river runoff dumped sediment and debris on the beach.

While such rain events will always cause floods, saving open space along waterways can significantly reduce their extent, say environmental advocates.

Donald Hey, director of Wetlands Research, Inc., points out that artificial systems — canals, pipes, culverts, parking lots, buildings, and drains — aggravate flooding by forcing fast-moving water through erosion-prone passages. Instead of holding the water for the time it needs to soak into the ground, these systems move water off the land quickly. Hey says that restoring wetlands, prohibiting development in floodplains, and slowing water are the best ways to control floods.

Currently, excess nitrogen and phosphates flowing off the land cause catastrophic damage to aquatic systems. But wetlands planted on floodplains can remove these pollutants, pull carbon dioxide from the atmosphere, and clean and store rainwater.

Wetlands Research is proposing that industries and cities that discharge water purchase “nutrient removal credits” for the services wetlands provide. The money would be used for restoring millions acres of wetlands that have been lost. Hey believes that this “nutrient farming” is the future of flood control.

Hey looks to the future and sees a healthier landscape. “Picture in your mind these perpendicular structures, these weirs, going all across the river, blocking the water, holding it back, creating pools. Our streams would turn into a series of ‘riffle, pool, riffle, pool’ that would slow the water down. The result is cleaner water, less flood damage, and a better environment for humans.”

— Elizabeth Riotto