People look to the U.S. Supreme Court for clarity. In a wetlands case decided recently, the court muddied the water instead. Fortunately, a dramatic shrinking of the Clean Water Act’s reach, which was espoused by the conservative wing of the court, failed. Instead, the court supported limiting the reach of wetlands rules. Unfortunately, the limits to that reach weren’t clearly articulated, leaving regulators, developers and attorneys to figure it out. The Army Corps of Engineers, with help from Congress if necessary, can improve the situation by clarifying when a waterbody is a wetland and when it is not.

Arguments before the court involved two Michigan cases. In one, a developer was accused of destroying wetlands without a permit on three sites. Federal regulators are seeking up to $13 million in restoration work and fines. According to the developer, the nearest tributary is 20 miles away and the only water from his property that would reach it would be runoff.

In the other case, a group sought to build condominiums on land near Detroit separated from tributaries of Lake Huron and Lake Erie by a manmade barrier. In both instances, the Court of Appeals ruled that the Clean Water Act applied to the properties because they were hydrologically connected to a navigable waterway. Both parties appealed to the Supreme Court.

Four members of the court sided with the developers. Writing for this group, Justice Antonin Scalia wrote that protection of “waters of the United States” includes only those that are “relatively permanent, standing or continuously flowing.” This narrow interpretation would include rivers, streams and lakes, but not intermittent streams, wetlands or vernal pools, as Maine recently included in its wildlife habitat protection rules.

Four justices ruled that the Army Corps of Engineers was within its rights to prevent degradation of federal water resources. Justice Anthony Kennedy staked out the middle ground. His opinion, which become controlling law because of the split on the court, said that allowing federal regulation anytime a hydrological connection exists is too liberal an interpretation of the Clean Water Act. “Absent some measure of the significance of the connection for downstream water quality, this standard is too uncertain,” he wrote.

He then came up with his own test allowing federal regulation of wetlands only when they have a “significant nexus” to a major waterway. He added that in both Michigan cases, the Corps of Engineers had some evidence of this type of connection.

Fellow justices, from both ideological camps, as well as developers and environmental groups criticized the Kennedy test for being vague and creating more work and uncertainty for developers and regulators.

To avoid this unacceptable situation, the Army Corps of Engineers should clarify when a wetland is connected to a navigable waterway, triggering federal review.