Jan 18 – The long-awaited $25 million Portland Harbor dredging project gets underway Monday as contractors begin digging a 20-acre pit in a shallow bay in South Portland, home to seven decades of industrial sins of a working waterfront will be buried over the next three winters.
Massachusetts-based Cashman Dredging will use a ship-mounted crane to dig a confined water storage cell (CAD) to be filled with contaminated sediments that have accumulated around the piers, marinas and wharves, destroying the port’s economic vitality suppressed and the health of the port is threatened. Casco Bay.
With that sediment gone, the waterfront will reclaim ship moorings lost during low tide. And the occasional ship’s propeller or keel digging into the bottom or a storm surge won’t stir up such a toxic brew after the cleanup.
It’s been a long time coming, says Bill Needelman, Portland waterfront coordinator.
“The conversation about dredging the Port of Portland goes back at least 30 years,” he said. “Projects like this are notoriously difficult to execute. Getting all the parties to agree, getting all the permits, getting all the financing, it’s very difficult. And every year of delay makes it even more difficult.”
The shipping channel connecting the Port of Portland and the Gulf of Maine is dredged approximately every fifteen years, most recently in 2014, by the U.S. Army Corps of Engineers. It is up to the owners or the city to remove sediment that accumulates between piers, wharves, marinas or boat docks.
But the sediment deposited in Portland Harbor’s working waterfront as a result of three-quarters of a century of industrialization is too polluted to be dumped into the sea. Tests showed it was high in the remains of fossil fuels, heavy metals such as zinc, mercury, copper and lead, and pesticides.
Transporting it to a hazardous waste landfill was too expensive for individual property owners.
In 2007, about 15 years after it was formed in response to toxic chemicals in the harbor, the Casco Bay Estuary Partnership commissioned a study that found that the only cost-effective approach to cleaning up and removing these dredged soils was to build a CAD would be. cell.
The Estuary Partnership’s research launched the search for funding, permits and an acceptable cemetery. And by acceptable, that meant a stretch of ocean floor outside shipping lanes that could support a cell without exploding, while avoiding power lines, bird hotspots, boating areas, beaches and lobster grounds.
“The big story here is the level of public and private collaboration that took place to get this done,” Needelman said. “It was truly amazing. All levels worked together toward a common goal, which was to preserve port in the Port of Portland.”
The final piece of the puzzle fell into place last January, when the state released $10 million in funding for the project after Portland cut the project cost from $32 million to $25 million. In 2023, state lawmakers changed Governor Janet Mills’ budget proposal to include American Rescue Plan Act funds for the project.
Over the years, the project has won a diverse group of supporters in Southern Maine’s fishing and business communities, as well as environmental groups, who, like the Estuary Partnership, want to clean up the state’s busiest commercial port.
According to the Portland Regional Chamber of Commerce, Portland Harbor generates a total of approximately $800 million in economic output that can be tied to its working waterfront. According to state data, 516 fishermen landed more than 14 million pounds of fish and lobster in Portland Harbor in 2023.
Portland Discovery Land & Sea Tours has been operating in Casco Bay for 25 years. In the early days the moorings at Long Wharf and Fisherman’s Wharf had a depth of 2.5 meters at low tide, but now the tour boats are often forced to moor in less than 1.5 meters of water.
“Our ships often have to push through mud to operate,” says co-owner and voyage captain Bill Frappier. “This situation becomes more dire with each year without dredging. The project is essential to the success of our company.”
During full or new moons, tides in Portland Harbor can drop as much as 10 feet. At low tide, boats often become stuck in the mud, forcing them to lift their motors or use poles to fight their way out. Although the depth boats need varies by size, lobster boats generally need 2 or 3 feet of water, a ferry 8 to 10 feet, and a large herring boat up to 15 feet.
The lack of moorings has created a Catch-22 situation, said Phineas Sprague Jr., president of Portland Yacht Services and Portland Ship Yard. Wharf owners lose money, leaving them no choice but to charge more for the remaining berths. That puts pressure on the commercial fishing sector.
“There will be no next generation of commercial wharf workers,” Sprague said of wharf owners before the latest dredging grant was approved, signaling the project was a reality. “Most of my friends have left the waterfront and I will not allow my children to work in my business. My time is limited.”
Windham lobsterman Bill Coppersmith, who fished out of Portland Harbor for four decades, agreed that a lack of sufficient moorings was hurting local fishermen. Without dredging, local lobster fishermen lost direct access to their workplaces and international markets, he said.
“More than seven decades of silt buildup has cut off hundreds of feet of shipping connections and timely access to the waterfront facilities we rely on to safely and efficiently land and ship our product,” Coppersmith wrote in voicing support from the Maine Lobstering Union pledged for the project.
Friends of Casco Bay are pleased that the cities and harbor commission agreed to locate the CAD well in an area outside of productive lobster grounds and designed the project to cause minimal damage to the environment during dredging .
“While most support will focus on the significant economic impact the dredging will have on Portland and South Portland, we are focused on this unprecedented opportunity to remove legacy contaminants,” Casco Baykeeper Ivy Frignoca said in one of her letters of support for the project.
It’s an “ideal time” to remove the harbor’s toxic sediments, which will improve both habitat and public recreation, as Portland and South Portland also take steps to reduce their sewer overflows and stormwater runoff into the harbor, Frignoca said .
This will be Maine’s first CAD, but the concept is not new. The technique has been used safely in waters around the world, according to the Environmental Protection Agency, which authorized the Maine CAD. There are CADs in Boston Harbor; New Haven, Connecticut; Providence, Rhode Island; and even the St. Louis River.
The Portland CAD will be dug in a shallow, little-used bay in South Portland, just downstream of the Casco Bay Bridge, between South Port Marina and Coast Guard Station South Portland. The 9-hectare trapezoidal cemetery will be 15 meters deep at its deepest, with sloping sides approximately 250 meters long and 120 meters wide.
Clean silt, marine clay and glaciers will be removed to create the CAD cell, and the sediment will be taken by barge to an open ocean dump about 7 miles (11 km) from Dyer Point in Cape Elizabeth. Two or three tugboats and scows will make as many as five trips back and forth a day during the month-long excavation.
The dredging season ends on March 15, meaning any construction noise will be muffled by seasonally closed windows. There were no complaints during the last federal dredging of the canal, Needelman said, and that process required blasting. Not this one.
Once the pit is dug, the project will enter its second phase: dredging approximately 245,000 cubic yards of contaminated sediment from 47 areas on the Port of Portland waterfront, including 19 piers, 10 marinas and boatyards, the Portland Public Boat Launch and the commercial port of Portland. landing of a barge.
Dredgers transport the contaminated sediment from the quay or pier to the CAD and discharge their cargo directly above the well. Project officials plan to use a seasonal layering approach to disposal, placing each season’s most contaminated dredged material beneath the cleaner dredged material.
Project officials say the contaminated dredged material will be more stable if buried in the CAD than where it is now. In the CAD it is buried under a layer of clean fill at the end of each dredging season. Because the CAD will be “over-excavated”, natural sedimentation will cover it at a rate of about 2 inches per year.
Dredging the equivalent of 24,500 dump trucks full of mud will take about three winters. Officials will continue to review the budget, looking for ways to reduce costs and increase participation on the waterfront, but at this time, disposing of dredged material at the CAD will likely cost about $35 per cubic yard.
Needelman hopes construction of the CAD can be completed within a month so that the contractor can be asked to extend his stay and complete initial dredging work at the port this winter. First up would be the Maine State Pier and Ocean Gateway, for which permits and funding are already in place.
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