HAMPTON, VA. -- It took the Virginia Department of Transportation nearly 10 years to build an expressway here, and now the department may have to pay $1 million or more because federal wetland regulations changed drastically over the course of construction.

The U.S. Army Corps of Engineers claims that the state destroyed 40 acres of wetlands in building a 2.3-mile stretch of the East-West Expressway here. The state contends that six acres were disturbed.

When the state began planning the expressway in 1981, it filed the necessary environmental reports, according to Melvin H. Thomas, the department's environmental program manager.

In 1984, he said, federal officials concluded in the parkway's environmental impact study that the area contained no "significant" wetlands. Regulations in 1984 stated that wetlands that do not flow into any body of water can be destroyed without a permit from the corps. Since then, wetland regulations have changed twice.

The 1986 regulations, which the transportation department was told to follow, Thomas said, allowed one acre of isolated wetlands to be destroyed without a permit and 10 acres to be destroyed after the corps was notified and approved the action, known as "approved notification." The department received that approval, he said.

The 1988 regulations required permits to destroy any wetlands.

"The rules have changed several times during the game," Thomas said. "Highway projects are not something you do overnight. They take an average of 10 years. With the Hampton Roads parkway, the rules changed drastically."

The transportation department may have to buy land with damaged wetlands and cultivate them until they're healthy or buy land and create wetlands -- a complicated and often unsuccessful task, said a corps spokeswoman, Diana Bailey.

She would not estimate what it might cost the transportation department.

"I've heard the $1 million estimate, but if we have to do 40 acres, we'll be very lucky to do it for $1 million," Thomas said. "We're definitely going to have a hard time complying with 40 acres. Six acres we can probably do."

Non-tidal, or inland, wetlands can be bogs, swamps or even woods with a soggy surface.

Wetlands are important here, scientists say, because they store water and filter it before it reaches Chesapeake Bay. They also provide a habitat for wildlife and plants that cannot grow elsewhere.