But Commissioner Gary V. Hodge also said officials are considering a proposal to reduce the size of the development district by 40 percent to 50 percent, channeling more growth to the Waldorf area.
The highway would still be needed, he said, not to ease commuting to Washington but to link the rural, poorer part of the county with jobs along U.S. 301.
"We need to have a more efficient, environmentally sensitive way of crossing the county," he said, "with a road that's deliberately engineered and designed to protect the environment."
Activists say the creek and its watershed are too valuable to take a chance.
"It's not a good place to push your growth," said Bonnie Bick, a leader of the Southern Maryland group of the Sierra Club. On a walk through woods to the creek, she pointed out spring beauties poking their tiny white flowers from the awakening soil and shadbush blooming along the shore.
It was too early to see the potato dandelion, a rare plant that looks like but is not related to the common yard weed. More abundant in the Southeast, the plant is classified as endangered in Maryland. Some were spotted on a farm in the highway's path last spring.
Bick recalled that the highway was planned decades ago in part to serve then-planned development of Chapman's Forest, a 2,000-acre tract along the Potomac. In the 1990s, she and others convinced the state to buy the land and preserve it. The highway, Bick said, needs to be re-evaluated and growth redirected to areas like Waldorf.
Fishermen canvassed along the creek on a recent weekday tended to agree.
"There's just too much development going on right now, way too much, and it's destroying recreational opportunities for people," said Everett Boston of Morningside.
He was fishing from the dock at Smallwood State Park, near where the creek joins the Potomac. Bass boats came and went regularly, as fishermen prepared for a weekend tournament.
"It's a beautiful waterway, a fabulous fishery," said Andy Andrzejewski, a fishing guide from La Plata who had just returned to shore. "You can see bass spawning ... in the grass." The creek, with its lush underwater grass beds, teems with large mouth bass.
"Mattawoman Creek is probably the best bass fishery on the entire East Coast," said Scott Sewell, conservation director for the Maryland Bass Federation.
