Dominion Power has proposed installing towers across the James River that would be visible from College Creek Beach on the Colonial Parkway. Local history buffs and nature lovers are trying to protect the scenic beauty of the area. (Scott Neville/For The Washington Post)

State regulators in Richmond have approved a controversial request by Dominion Power to build a 500,000-volt transmission line over the James River — a plan that faces heavy opposition from preservationists and other organizations around America’s founding waterway.

The State Corporation Commission of Virginia approved the plan Tuesday, much to the dismay of critics.

Now, the focus — and fight — moves to the federal level. The project requires a permit from the Army Corps of Engineers, and the groups that have denounced Dominion’s plan on historic and economic grounds say they’re digging in.

“The state decision is profoundly disappointing, but the fight is hardly over,” said Rob Nieweg of the National Trust for Historic Preservation, which promises to be “a very active participant” in the Army Corps review process. “We think the SCC missed the mark, but we hope the Army Corps will take a hard look at this and make a meaningful evaluation of the historic and environmental impacts of Dominion’s plan.”

The utility’s 7.4-mile transmission line would span the same stretch of river that some of the first English settlers navigated in 1607 before landing at Jamestown. It would cross the James on a series of as many as 17 towers — the largest being nearly as tall as the Statue of Liberty and, critics say, be visible from the tip of Jamestown Island and along the historic Colonial Parkway.

In its final order, the commission said it understood “the importance of this case to the many people who cherish Virginia’s historical and natural assets and to those who depend on the reliable electric service so critical to Virginia’s economic strength, safety, and quality of life.”

But in a statement, the regulatory agency said it is tasked with determining “whether the public convenience and necessity require the construction of transmission lines in the commonwealth.” In the case of the James River proposal, “the evidence is clear that the proposed project is necessary to continue reliable electric service to the hundreds of thousands of people who live and work across this broad region of Virginia.”

Dominion, which has an old nuclear power plant across from Jamestown Island, said it needs to expand grid capacity and improve reliability around Hampton Roads. The utility’s planners determined that an overhead crossing downriver from Jamestown would be the most sensible option.

In a statement, Scot Hathaway, vice president of electric transmission for Dominion Virginia Power, said the company “is sensitive to historic and environmental concerns and the Commission ultimately agreed that the company’s recommended routes are the least impactful.”

The Colonial Williamsburg Foundation, the College of William and Mary, and Preservation Virginia are among those opposing the project. In June, the National Trust for Historic Preservation added the James River to its list of America’s Most Endangered Historic Places in an effort to amplify the controversy.

Anticipating the state’s decision, Nieweg and several other opponents of Dominion’s plan met last week in Washington with aides to Sen. Mark R. Warner (D-Va.), Sen. Timothy M. Kaine (D-Va.) and Rep. Rob Wittman, the Republican whose district includes Jamestown and Williamsburg.

The opponents’ message: Help.

“We need national support,” said Margaret Nelson Fowler of the Save the James Alliance, which residents formed to fight Dominion’s plan. “The SCC’s decision was a foregone conclusion that convinced us even more of the need to press this at the federal level.”

Fowler and the project’s other opponents — including James City County and the mayor of Williamsburg — had urged state regulators to force Dominion to come up with another plan, such as an underwater crossing or a different route.

But the SCC said in its final order that there were no viable alternatives. “The Commission can no more ignore the severity of fast-approaching reliability problems than it can the environmental, scenic, and historic impacts associated with the many different possible alternatives explored in this case for addressing those problems.”

According to the utility, construction of the transmission line could begin before the end of the year. The SCC ordered Dominion to finish the project by June 1, 2015.