W. Michael Sullivan, right, of the Department of Environmental Management, speaks at yesterday’s ribbon-cutting.

The Providence Journal / Mary Murphy

CUMBERLAND — The wooden boardwalk runs along the upper edge of the Lonsdale Marsh, offering pedestrians and bicyclists an up-close view of what officials call a tremendous turnaround in one of the largest marshlands in Providence County.

Fourteen feet wide and 540 feet long, the boardwalk opens a path through the reclaimed wetlands that today are a popular nesting place for Eastern screech owls and a variety of ducks.

Amid the densely packed residential development of Valley Falls, it’s not unusual to catch great blue heron, swans and osprey floating on the waters. The marsh is a stopover on the migratory flight pattern of waterfowl.

It was not always like this. Privately owned, the marsh had been an unofficial dumping ground until the town purchased its 30 acres some 18 years ago and incited a cleanup effort to the restore the natural habitat. “We pulled thousands of tires from there,” recalled Robert Billington, executive director of the Blackstone Valley Tourism Council.

Largely completed late last year, the boardwalk is part of a new, one-mile segment of the Blackstone River Bikeway that received its official dedication from state, local and federal officials at a rainy morning ribbon-cutting ceremony yesterday.

The boardwalk, the centerpiece of the $3.9-million segment, was built upon a series of wooden stilts in order not to disrupt the developing habitat. All told, $21 million has been expended on the bike path since its first section opened in 1998 at the Ashton Viaduct in Lincoln. The federal government is financing 80 percent of the project, with the state covering the remaining 20 percent.

“This environmentally sensitive feature allows the bikeway to continue on an off-road path while not disturbing the flow of water in the marsh — something that is critical during times of high river levels,” explained state Department of Transportation Director Michael P. Lewis. “Combined with the restoration of the Lonsdale Drive-In into a scenic meadow and wetland, these projects improve the ecology of the river while allowing everyone access.”

At the ceremony, representatives from the National Park Service also announced the debut of the Blackstone River Valley Bikeway Patrol — volunteer cyclists who will ride the path and help visitors with everything from patching flat tires to giving historical tours.

Construction on the mile-long section of path started in late 2006 and was mostly completed by last December, according to state DOT spokesman Charles St. Martin.

The section begins at the former Lonsdale Drive-In on John Street in Lincoln. It follows the John Street Bridge into Cumberland and then crosses the street into the woods along the marsh to the boardwalk.

From the marsh, cyclists take a handful of local roads that have been recently repaved as part of the project until the entrance to the Valley Falls Heritage Park, located across the street from Cumberland Town Hall on Broad Street. That park is currently the southernmost terminus of the bikeway, which now totals 10.3 miles.

At its northern end, the bike path just crosses into Woonsocket, at the city’s wastewater treatment facility on Manville Road. The state DOT and the city are working on two segments totaling 1.3 miles and costing $1.5 million that will push the path farther in Woonsocket, near the middle school under construction at Davison Avenue. Those segments are slated for completion at the end of the year.

The state DOT is also in the planning stages of constructing three other segments to the bike path, two of which would extend the path south into Central Falls, Pawtucket and Providence, and one that would take it to the Massachusetts state line in Woonsocket.

The goal is to link the Blackstone Bikeway with the East Bay Bike Path, via India Point Park and the Washington Bridge in Providence. When it is completed, the Blackstone Bikeway will span 19 miles, making it one of the longest of the bike paths in the state.

The efforts to build a north-to-south bikeway in Rhode Island are being mirrored in Massachusetts. Long term, the goal is to create a 48-mile bike path from Providence to Worcester that officials see as an important transportation link between the two cities.

“In addition to its wonderful recreational qualities, this pathway is fast becoming a transportation alternative for many and a signature asset of the National Heritage Corridor,” said Jan Reitsma, executive director of the John H. Chafee Blackstone River Valley National Heritage Corridor Commission.

pmarcelo@projo.com