A federal judge says a South Carolina Supreme Court decision in a dispute over the $650 million deepening of the Savannah River shipping channel may raise new and difficult legal issues that the federal court may have to resolve.

And in an order, U.S. District Judge Richard Gergel has asked the parties in a federal lawsuit to try to mediate their differences.

The state Supreme Court ruled last week the state Department of Health and Environmental Control violated state law in certifying a federal water quality permit for deepening. That decision means there is no needed South Carolina permit approval in place.

In the case before Gergel, environmental groups say a state pollution control permit is also needed.

The Georgia ports want the channel deepened to handle larger container ships.

Tags: federal judge, South Carolina Supreme Court, Savannah River deepening, mediation, federal water quality permit