The Environmental Protection Agency says a rule it proposed this week merely clarifies its existing authority over the nation's waterways.

Republicans say it's "the biggest land grab in the history of the world," as House Appropriations Committee Chairman Hal Rogers, R-Ky., called it.

There is some certainty about the EPA's rule defining the waters of the United States -- the buzz it has generated is not going away any time soon.

The EPA, in conjunction with the Army Corps of Engineers, says the proposed rule would clarify which streams, rivers, wetlands and other waterways are within its regulatory jurisdiction. It would bring a majority of those waterways under EPA control, which drew backlash from conservatives and industry groups.

The proposed rule has been on Republicans' radar for several weeks. The House Committee on Science, Space and Technology has raised the issue often, and the rule touches a variety of committees because of its potential impact on economic development, permitting and the environment.

"The only certainty I see comes in the form of more mandatory permits for the jurisdictional waterways," House Appropriations Subcommittee on Interior, Environment and Related Agencies Chairman Ken Calvert, R-Calif., said during a Thursday hearing.

The EPA contends the rule would provide certainty for businesses about whether they need permits for activities near those waterways, and that the agriculture sector will benefit from more clearly defined exemptions. It also says the rule doesn't extend the agency's reach through the Clean Water Act.

"We're not expanding the types of waters that we have traditionally and historically been regulating," EPA Administrator Gina McCarthy said during the hearing.

McCarthy said the benefits would outweigh the costs of implementing the rule. She said various sectors of the economy had asked for an update to the rule, which would provide new maps outlining which waterways are in the EPA's jurisdiction.

But Rogers said he's also heard from the business community.

"We've heard from the same people — and they're in an uproar," he said.