"A plurality of the Supreme Court concluded on Monday that the Clean Water Act's protection of "waters of the United States" is limited to those bodies of water that are "permanent, standing or continously flowing," and thus does not embrace channels through which water flows only some of the time. And, the Court added, "navigable waters" under the Act ordinarily is no broader than U.S. waters. The decision appeared to rule out protection against filling-in or pollution of wetlands not part of actual waterways."