A battle for water has erupted in Southeast Virginia, pitting environmentalists and local Indians against a proposed 13-billion-gallon reservoir intended to meet the water needs of Newport News and its surrounding area through 2040.

The proposal from a group lead by the Newport News Waterworks calls for creating a 6-mile-long reservoir in the Mattaponi River watershed that would run diagonally across King William County.

The project, which would be built on Cohoke Creek, would flood 524 acres of wetlands and 1,457 acres of upland forest.

The issue is not unique to Newport News. Battles over water supplies have been cropping up throughout the Bay region in recent years as growing areas struggle to find water to meet their needs. Until recently, nearby Virginia Beach was engaged in a controversial bid to transfer water from Lake Gaston, in North Carolina, to meet demand.

The proposed King William Reservoir would get up to 75 million gallons a day from the Mattaponi River to supply the Williamsburg-Newport News-Hampton area.

Environmentalists have charged that the region is trying to secure more water than it needs to support additional development that will sprawl over the landscape in the future. The Sierra Club, as part of a national campaign against urban sprawl, has decided to oppose the project.

"It was clear that from Los Angeles to Atlanta, and from Minneapolis to Tampa, people were concerned with the uncontrolled growth that was just chewing up our countryside, increasing air pollution and causing congestion," said Glen Besa, the club's regional representative.

But Barry DuVal, president of the Hampton Roads Partnership, called the Sierra Club's view of the project "misguided and inaccurate."

"This is a 'smart growth' project," DuVal said. "It encourages the use of existing infrastructure in developed areas and discourages the very unplanned growth the Sierra Club claims to be targeting as their cause."

David Morris, planning and programs director for Newport News Waterworks, the reservoir's lead developer, said fighting sprawl should mean encouraging development in places where the infrastructure is already in place.

Environmentalists say the project would mar the relatively undeveloped Mattaponi, which has been studied as a potential scenic river by the National Park Service. They say the project would threaten bald eagle nesting sites, rare plants' habitat and could draw salt water further up the river, affecting aquatic ecosystems.

In addition, the Mattaponi Indian tribe contends the proposed reservoir is an unwanted intrusion into a 3-mile buffer zone around its reservation and violates a treaty that dates to 1646.

The debate, which has been going for months, appears likely to continue well into the summer.

The U.S. Army Corps of Engineers, which has to approve the project, recently extended the public comment period until July 25 at the request of the EPA, which says it wants more time to review the plan. The comment period had been set to expire May 26.

Late last year, the project was downsized by about 8 billion gallons after the EPA and the state Department of Environmental Quality expressed concerns about the project's size and the amount of wetlands impacted.

- The Associated Press contributed to this report