HAGERSTOWN, Md. -- Supporters of the Chesapeake and Ohio Canal National Historical Park are seeking state help in closing a nearly three-mile gap in the towpath that has sent hikers and bikers on dangerous detours for more than a decade.

Washington County's delegation to the General Assembly voted last week to request a $200,000 bond bill to pay half the cost of an engineering study for rebuilding a washed-out trail section along a stretch of the Potomac River called the Big Slackwater.

The National Park Service would contribute another $170,000. The remaining $30,000 would be shared evenly by the nonprofit C&O Canal Association and the Hagerstown-Washington County Convention and Visitors Bureau.

"I think this partnership is the only way we're going to move forward," Sen. Donald F. Munson told The (Hagerstown) Herald-Mail.

The Big Slackwater is a wide section of river behind Dam No. 4 near Downsville. Flood waters ruined a 2.7-mile section of trail there in 1996, creating the biggest gap in the towpath's 184.5-mile route from Washington to Cumberland.

Park Superintendent Kevin Brandt said more than 30 people have been hurt over the years along a detour that follows narrow, two-lane country roads.

The towpath, once used by barge-pulling mules, attracts 700,000 users annually in Washington County alone, said Tom Riford, president of the local tourism bureau. That number is expected to climb this spring as bikers take the newly completed Great Allegheny Passage from near Pittsburgh to Cumberland, and the C&0 towpath from Cumberland to Washington, D.C.

The engineering study would determine the scope and cost of reconstruction at Big Slackwater, Mr. Brandt said. Previous estimates have run as high as $15.5 million but Mr. Riford said that was for a path 10 feet wide. A narrower trail would cost significantly less, he said.