Dams alter water quality, the U.S. Supreme Court ruled recently in a case involving Maine’s S.D. Warren Co. The unanimous ruling sends an appropriately strong signal that states have the power to regulate dams to restore or maintain fish runs.

S.D. Warren, a subsidiary of SAPPI, owns and operates five dams on the Presumpscot River to produce power for its Westbrook mill. The dams are licensed by the Federal Energy Regulatory Commission every 50 years.

In 1999, the company applied to the Maine Department of Environmental Protection for water quality certification as part of its FERC license renewal process. The company applied to the DEP under protest claiming it didn’t need state jurisdiction because its dams did not meet the “discharge” provisions of the Clean Water Act.

In its certification, the DEP required the company to maintain minimum stream flows and to provide passageways for migratory fish and eels. FERC incorporated the state’s conditions into its license renewal and required the installation of fish passageways on all five dams. The company sued.

The Cumberland County Superior Court and Maine Supreme Judicial Court rejected the company’s argument, which simply was that its dams did not discharge anything into the river and therefore were not subject to state regulation. The company argued that Congress intended that something – pollutants, heat – had to be added to the water for it to qualify as a discharge.

The court, relying on the dictionary definition of discharge, disagreed. Discharge, Justice David Souter wrote for the court, meant “flowing or issuing out” whether or not the water contained a pollutant. “… this Court has not been alone, for the Environmental Protection Agency and FERC have each regularly read ‘discharge’ as having its plain meaning and thus covering releases from hydroelectric dams,” the 15-page opinion said.

Later the court said: “Warren itself admits that its dams can cause changes in the movement, flow and circulation of a river … caus[ing] a river to absorb less oxygen and to be less passable by boaters and fish.”

This led Justice Souter to conclude: “Changes in the river like these fall within a state’s legitimate legislative business, and the Clean Water Act provides for a system that respects the states’ concerns.”

Because there are more than 1,500 hydroelectric dams throughout the country, this case was closely watched with 33 states filing briefs in support of Maine’s position. Although they generate electricity without emitting air pollutants, they do alter rivers and the surrounding landscape.

“It was beyond ludicrous for S.D. Warren to argue that its dams didn’t have to comply with the Clean Water Act,” said Rebecca Wodder, president of American Rivers, which supported Maine’s position. “This is a victory for rivers, for clean water, and most of all for good old common sense.”

The Supreme Court’s ruling reaffirms the strong role states play in water quality and dam licensing decisions. It also reaffirms that states can require changes to dams to allow for fish passage, an important part of fish restoration projects.