A bulldozer plows through what was once an impenatrable 8-foot-tall phragmite thicket Monday.

SAKONNET AREA — Bulldozers launched a frontal assault last week on the 8-foot tall phragmites that decades ago choked virtually all other life out of Portsmouth's Boyd's Marsh. By Friday, better than 20 acres had been flattened, the first stage in an Army Corps of Engineers operation designed to restore the stagnant property, evict the mosquitos, and make way for fish, shellfish and shorebirds.

In the works for the better part of a decade, the Corps' $3.5 million "Town Pond Project," named for a time when there really was a pond here, should be complete by June of next year, according to Thomas Ardito, director of policy and communications with the Narragansett Bay Estuary Program.

When complete, the area will be transformed. Twenty-two of the 40-plus acres will have been scoured out to create waterways deep enough for fish to swim and kayaks to explore, even at low tide. These waterways will be fed by a new opening to Mount Hope Bay. Pathways open to the public will surround much of the marsh.

The Army Corps first proposed the project back in the late 1990s as a way to undo harm it had done over half a century earlier. Back then it had used the marsh's opening on the north shore of Portsmouth to dump many bargeloads of mud dredged from the Mount Hope Bay shipping channel. That mud blocked the tidal flow of bay water and the marsh was soon overrun by phragmites and mosquitos — a far cry from the navigable pond described by town founder Anne Hutchinson and crew who supposedly made landfall near Founder's Brook via the pond.

In the years since the Army Corps first introduced the restoration idea, the cost and the project itself have evolved.

Initially, the Corps figured it would cost about $1 million to do the work, an estimate that has expanded more than three-fold. Northern Construction Service LLC of Weymouth, Mass., is doing the work for $2,946,300. The balance of the $3.5 million total went into design, engineering and other costs. As usual in such cases, the Corps is paying 75 percent with the state and area foundations paying the rest.

Although the marsh builders are working from a carefully designed plan for the new waterway, Mr. Ardito said some details must be left to Mother Nature' discretion.

"One thing we have learned from doing these things is not to get too fancy with the channel designs," Mr. Ardito said. "Once the water starts flowing, it usually has its own ideas on where to go."

Thus, the channel entrance at the north end of the new marsh is relatively straight. It will pass through a cut in the beach, south beneath the railroad bridge and on into the pond. Depths throughout will be about a couple of feet at low tide, deep enough, Mr. Ardito said, for the many species that will live and spawn there.

It is an ambitious project, he added — the biggest such marsh construction on Narragansett Bay.

"I think people will be thrilled with the way this turns out," Mr. Ardito said.

One concern from the outset was what to do with the several hundred thousand cubic yards of muck that must be scooped out to sculpt the new pond. There had been talk of using it as landfill cover but the silt is so fine that landfills are reluctant to accept it.

"And trucking it off-site would have been prohibitively expensive," Mr. Ardito said.

Instead, it will be kept within the restoration site. Most of the mud will be lugged to the marsh's northeast side where it will provide the foundation for a "high marsh" covered with grasses typically found in slightly higher elevation areas that surround marshes.

One section left relatively untouched will be a strip of large utility poles down the middle. These carry much of the electrical power used by Aquidneck Island from Brayton Point.

"We asked them if these could be moved ... they laughed at that one," Mr. Ardito said. Although that strip is state-owned, like the rest of the marsh area, the electric company holds a lease for its use. Moving the poles would have been too expensive but visitors will be able to walk in that raised part of the marsh.

For now, bulldozers are plowing over the phragmite thickets. When that is done, they will start digging out the waterways, until pausing for winter. When earth moving is complete next spring, the marsh will be seeded with native grasses and other plants. The final — and most dramatic moment — will be the day that the temporary dam is lifted and water is allowed to flow in for the first time.

Although the design is set, eventual uses of the property aren't final. Mr. Ardito said meetings will be held with the town, as promised, at which neighbors and other residents may offer suggestions and concerns. In general though, it is expected that people will be able to paddle kayaks in the waterways, and walk through the upland marsh areas and walkways.

Public access via a parking lot and viewing area are planned along Anthony Road at the pond's south end, not far from the Roger Williams University dorms — just west of the construction equipment staging point on Anthony Road.

Marsh numbers

* Acres to be restored — 40-plus

* Acres of open water — 22

* Cost — $3.5 million (actual constuction — $2.9 million)

* Cubic yards of fill to move —

* Depths of open water areas (at mean low tide) — about 2 feet

* Completion date — June, 2006

Marsh partnership

Lead organizations:

U.S. Army Corps of Engineers (fed. sponsor)

R.I. Department of Environmental Management (current non-fed. sponsor)

Narragansett Bay Estuary Program (non-fed. sponsor until about a year ago; led project planning and fundraising efforts; now leading coordination with non-governmental and local partners)

Supporting organizations:

Town of Portsmouth

Aquidneck Is. Land Trust

Commonfence Point Improvement Assn.

Ducks Unlimited

R.I. Corporate Wetland Partnership

R.I. Coastal Resources Management Council

Roger Williams University

R.I. Habitat Restoration Team

Probably R.I. Dept. of Transportation in the near future

R.I. Mosquito Abatement Coordination Program (part of DEM but deserves special mention)

By Bruce Burdett

bburdett@eastbaynewspapers.com