How far can the EPA go in regulating development is about to come to a head with two Michigan cases that will be heard in the Supreme Court. The cases involve developers who wanted to build on wetlands but ran foul of state authorities enforcing federal law, reports the New York Times.

One developer filled in his site when he had been told not to do so and the other was refused a permit by the Army Corps of Engineers. Experts say that if the developers win, the reach of the Clean Water Act could be restricted to navigable rivers and lakes.

Under the current interpretation of the law, any water that can drain into those rivers or lakes is covered by the federal law. Environmentalists argue that it has to be that way or else states and private owners would have a perverse incentive to pollute or otherwise damage the environment upstream because those downstream would pay the price of toxic water or dry riverbeds.

Several Western water authorities have joined a brief to argue that Congress can only control water as it affects navigation. That would be the most restrictive interpretation and give states the greatest control over water. In Western states the water itself and how to shift it around is a bigger issue than the chemicals and sewage that might be put into it.