The cases, both from Michigan, challenge regulators' definition of federally protected wetlands under both the Clean Water Act and the Constitution. The question is whether the federal government is properly asserting jurisdiction over wetlands that may be part of a drainage area or tributary system but do not actually abut the "navigable waters" to which the Clean Water Act refers.
If the government's view of its power under the statute is correct, the landowners bringing the appeals argue, then Congress has exceeded its authority and the Clean Water Act, in this application, is unconstitutional.
The answer to the statutory question has been in some dispute in courts around the country, especially after the Supreme Court's ruling in 2001 that the use of isolated ponds by migratory birds was not sufficient to give the federal government jurisdiction over those ponds under the Clean Water Act.
But no federal court has gone so far as to declare the Clean Water Act unconstitutional. The argument "lacks merit and does not warrant this court's review," Solicitor General Paul D. Clement told the court in the briefs the government filed in response to each of the appeals. The goal of protecting the nation's water quality "implicates core federal interests," Mr. Clement said.
While arising under a different environmental law, the new cases present an issue similar to one that gained some attention during the Senate confirmation hearings for Chief Justice John G. Roberts Jr.
As a federal appeals court judge, the new chief justice had voted in dissent to grant a new hearing in a case brought under the Endangered Species Act. The question in that case, Rancho Viejo LLC v. Norton, was whether the federal government could constitutionally assert jurisdiction to protect a species of toad that exists only in California and has no commercial uses.
Judge Roberts did not say that this application of the act would be unconstitutional in his own view, but rather that it was in tension with recent Supreme Court precedents giving a narrow reading to the power of Congress to regulate intrastate noncommercial activities. His opinion said that the appeals court should rehear the case in order to "consider alternative grounds for sustaining application of the act that may be more consistent with Supreme Court precedent."
Both the Endangered Species Act and the Clean Water Act have become enmeshed in the debate over private property rights versus government regulation.
John A. Rapanos, the Michigan landowner who brought one of the new appeals, has been a symbol of that debate for more than 10 years. Mr. Rapanos has been the subject of a civil enforcement action and criminal prosecution for acting without a permit to move earth and perform construction work on three multi-acre parcels that the Army Corps of Engineers and the Environmental Protection Agency deemed protected wetlands.
Last year, the Supreme Court denied review in Mr. Rapanos's appeal of his criminal conviction. The new case, Rapanos v. United States, No. 04-1034, is his appeal in his civil case, in which he faces millions of dollars in fines.
None of Mr. Rapanos's properties abut or drain directly into navigable waterways and, in fact, are up to 20 miles away from any navigable water. Two of the parcels are within the drainage system for Lake Huron, while water from the other runs off through a drain into a navigable river, the Tittabawassee.
In rejecting his appeal last year, the United States Court of Appeals for the Sixth Circuit, in Cincinnati, found that the properties were "interconnected with traditional navigable waters" and consequently fit the definition of wetlands. Only in a later petition for rehearing did Mr. Rapanos present his constitutional challenge to the Clean Water Act, so the appeals court panel did not have occasion to address it.
In his Supreme Court appeal, which was filed by the Pacific Legal Foundation, an organization in Sacramento, Calif., that advocates on behalf of private property rights, Mr. Rapanos is arguing that "the Constitution prohibits the federal government from regulating noneconomic intrastate activities like the filling of remote, nonnavigable, intrastate wetlands in this case."
The second Clean Water Act case the court accepted is quite similar, but in this case, Carabell v. United States United States Engineers, No. 04-1384, the property owners did seek a permit under the Clean Water Act to build a condominium complex on 19 acres of largely forested wetlands.
They filed suit when the permit was denied, now arguing that the property was not subject to federal jurisdiction. They maintained that an artificial berm that separated their property from a drainage ditch deprived their land of a "hydrological connection" with any navigable waterway. The Federal District Court in Detroit, as well as the Sixth Circuit, found that the property met the federal regulatory definition as "adjacent to tributaries of a traditional navigable water."
The court accepted a third Clean Water Act case on Tuesday that presents a different issue under a separate section of the law. The question in that case, S. D. Warren Co. v. Maine Department of Environmental Protection, No. 04-1527, is whether a dam through which water flows requires certification under the statute even if nothing is added to the water, either from outside or by the dam itself.
The Clean Water Act requires a "water quality certification" before making "any discharge" of a "pollutant" into navigable waters. The owner of five 100-year-old hydroelectric generating dams in Maine, which provide electricity to a paper mill, is arguing that flowing water does not constitute a "discharge."
The Maine Supreme Judicial Court rejected that argument on the ground that "water that has left its natural state and has been subjected to man-made control" could be considered a discharge. In this case, the state's environmental agency was administering the law in cooperation with the Federal Energy Regulatory Commission, which was reviewing a license renewal application from the company that owns the dams.
Separately on Tuesday, the court rebuked the Sixth Circuit for improperly dismissing a petition for habeas corpus from a man convicted of murder in the Michigan state courts. In an unsigned opinion, without dissent, the court said the petition filed by the defendant, Paul A. Dye, had been sufficiently precise in its allegation of prosecutorial misconduct and "it was error for the Court of Appeals to conclude otherwise." The case was Dye v. Hofbauer, No. 04-8384.