ROWLEY — Ox Pasture Brook is flowing freely toward the sea today, for the first time in about a hundred years.
A work crew last week began dismantling a stone-and-concrete Lower Ox Pasture Dam that had blocked the stream since the early years of the 20th century.
The dam created an approximately three-acre pond, but that's not all it did, said Alexander Hackman, a restoration specialist for the state Division of Ecological Restoration who is the site manager for the project.
Located deep in the woods off Central Street, the dam blocked tidal flow and degraded the habitat of several species of fish and plants, Hackman said.
Removing enough of the 200-foot-long dam to allow the brook to follow its natural channel will improve both the fish habitat and water quality, he said.
The free-flowing stream will also help nourish the Great Marsh by carrying sediment and nutrients into the tidal areas, he said.
"We want to give nature a little push in the right direction," he said.
The Lower Ox Pasture Dam project is the first one in Essex County, but the division is also looking at the eventual removal of the Larkin Mill Dam on the Parker River in Byfield, Hackman said.
The work in Rowley will take a total of about two weeks, with a budget of about $40,000, Hackman said.
The work is being spearheaded by the Division of Ecological Restoration but includes many partners, Hackman said.
The National Oceanic and Atmospheric Administration, U.S. Fish and Wildlife Service, the Corporate Wetlands Restoration Partnership, American Rivers, Trout Unlimited, and the Northeast Massachusetts Mosquito Control and Wetlands Management District have all contributed funding or expertise, or both.
Funding for the dam removal includes a grant from Trout Unlimited and American Rivers through a partnership with NOAA, and a donation of technical services from the Boston office of the international consulting firm ERM, according to a statement issued by the state Office of Energy and Environmental Affairs.
The Fish and Wildlife Service's Coastal Program and Partners for Fish and Wildlife Program also contributed funds for engineering and construction oversight, which has been provided by the consulting and engineering firm, Stantec of Topsham, Maine. In addition, the Northeast Massachusetts Mosquito Control and Wetlands Management District donated a portion of construction services, the statement said.
The brook and the dam are on public land, in the 2,000 acre William Forward Wildlife Management Area. Hackman said Central Street resident Tim Toomey has "graciously" allowed the work crew to move personnel and equipment across his private property.
Yesterday, a half dozen hard hat-clad workers were using an excavator to remove boulders from the stream.
Hackman said they would use a hydraulic power hammer to break up the concrete wall at the base of the dam.
Stantec staffer David Huntress reported that yesterday marked the first time that an incoming tide on the brook had overtopped the dam.
The stream was creating a discernible channel, meandering around chunks of ice that had fractured as the water beneath the ice surface of the pond dropped approximately 3 feet.
Gesturing upstream to where the pond was draining away, Hackman talked of future changes.
"This will all start to fill in with vegetation," he said. "Eventually, this will all be a natural wetland meadow."