The U.S. Supreme Court has ruled that the U.S. Army Corps of Engineers cannot consider a wetland “adjacent” to waters based on a series of hydrologic connections. Photo: Everglades National Park Photo

On June 19 the U.S. Supreme Court ruled 5–4 that the U.S. Army Corps of Engineers overextended its permitting authority under the Clean Water Act of 1972 by restricting construction near storm drains and ditches.

While the Clean Water Act allows the Corps to regulate development adjacent to navigable waters, wetlands, or tributaries adjacent to navigable U.S. waters, the ambiguous definition of “adjacent” prompted the court to examine how extensively the federal government can restrict development.

The court ruled that the phrase “waters of the United States” includes only relatively permanent, standing, or continuously flowing bodies of water, such as streams, oceans, rivers, and lakes—not storm drains, ditches, or channels that intermittently contain flowing water.

The court consolidated two cases in which the Corps claimed proposed development was too close to navigable waters or wetlands. One case examined construction of a shopping center near a man-made drain located 20 miles from a river; the other involved a condominium development near a ditch that drains into a creek that empties into a lake.