Solution to Dredging Dilemma at Portland Harbor’s Edges Lies Beneath

Charlie Poole remembers when lobster boats used to tie up at the head of Portland Harbor’s Union Wharf, the privately owned pier that has been in his family for generations.

But the slow buildup of silt carried down the Fore River and the sporadic bursts of sewer and stormwater runoff have robbed him of the five berths closest to Commercial Street. They also have forced those who used to tie up there to find dock space elsewhere, at one of the wharves that still have enough water for a boat to sit there without scraping the bottom. Tides can drop as much as 12 feet during full or new moons, and at low tide, Poole can look out and see a few boats in his other berths that are sitting in the mud, forced to lift their engines, if they can, and use poles to push their way out. It’s no way to operate a wharf, Poole said.

“Without a reliable, well-maintained berth, with proper water depth at all tides, we do not have anything to offer the marine business world,” Poole said of the public and private wharves in the oldest section of working waterfront in Portland Harbor. “Waiting for the tide to come in enough so an oil spill, pilot, lobster or any other type of vessel could leave its berth is absolutely unacceptable, and a commercial working port cannot operate that way. Proper water depth at the pier’s edge is the heart and soul of the dredging issue.”

Poole would like to dredge both sides of his wharf so he can get the bank financing he needs to make another $1.6 million investment in maintenance and wharf improvements. But the cost of disposing of the harbor-bottom sediments is prohibitive. These sediments are almost certainly tainted by the tanneries and foundries that once operated along the waterfront, as well as storm runoff and outflow from the city’s combined stormwater and sewage overflow pipes. The contamination has left him unable to cover the cost of disposing of the dredged remains, which could run as high as $200 per cubic yard, at a suitable upland disposal facility. Testing alone would cost him $80,000 a pop.

To help overcome the prohibitive cost of dredging, the Portland Harbor Commission is joining forces with the cities of Portland and South Portland as well as a handful of waterfront groups, environmentalists and some lobstermen. The commission is using a $350,000 federal Brownfields grant – the first one ever approved for studying contamination of submerged soils – to hire Campbell Environmental Group of Falmouth to determine how much silt needs to be dredged from between 22 public and private wharves in Portland Harbor. It also will determine, most importantly, the extent of the contamination, which previous tests suggest will include varying levels of heavy metals, pesticides and toxic chemicals.

FIRST ‘CAD CELL’ DISPOSAL IN MAINE

Portland is using $250,000 in state funding to pay Stantec, an Edmonton, Alberta-based engineering firm, to design and obtain permits to dig a deep hole in the floor of the harbor to bury the dredged soil in what is called a confined aquatic disposal – or CAD – cell, which would be capped with clean soil. This kind of disposal facility has been dug across southern New England, from Cape Cod to Boston to New Bedford, as well as across the world, from Los Angeles to Hong Kong, but it would be the first one in Maine. Federal tests of CAD cells built in Boston Harbor a dozen years ago have found no evidence that any of the buried toxins have escaped.

The U.S. Army Corps of Engineers, the regulatory agency that would permit a CAD cell, told local officials that the designing, permitting and construction of this kind of disposal facility is a “two-to-10-year adventure.” The total cost of dredging and disposal could run to $8 million to $14 million.

Project officials estimate they will complete the soil sampling this year. With that, they can calculate how much silt needs to be removed, and how much of it is too dirty to be dumped at sea. Clean dredged material from the shipping channel in Portland Harbor, for example, was dumped about 7 miles off the coast of Cape Elizabeth in 2014. At this point, however, project officials assume most of the dredged material removed from between the oldest section of working waterfront – initially estimated to be about 300,000 cubic yards – will be dirty.

Disposing of contaminated material isn’t cheap. Once it is excavated, wharf owners could dry it out and truck the silt to an inland waste disposal site that specializes in contaminated materials, but wharf owners say they can’t afford that cost, which would increase the cost of dredging tenfold. They could mix it with concrete and use it on site, as the foundation of a new building, like Poole did with some dirty silt he dredged to make room for the Responder, an oil spill cleanup vessel funded by the oil industry. That was expensive, too, but the revenue from the long-term berthing lease helped Poole convince a bank to loan him the money to do it.

Other harbors facing the same environmental needs and financial constraints have turned to CAD cells as a solution. Local players, including some lobstermen, are leaning that way, too.

Charlie Poole, president of Proprietors of Union Wharf, says that “without … proper water depth at all tides, we do not have anything to offer the marine business world.” At left, the channel in the central part of the harbor is dredged in 2014.

ENVIRONMENTAL GROUP ON BOARD

Environmental groups support the concept as “the least worst option” to remove the contaminated soil from the part of the harbor where storms, boat propellers and even the tides are constantly churning the silt, said Cathy Ramsdell, executive director of Friends of Casco Bay. If the group pushed for removal to an upland disposal site, the costs would be so high that the dredging would never happen and the environmental risk would grow each year with the muddy buildup choking the waterfront economy, Ramsdell said.

“None of the options are good. They all have environmental consequences, but we can’t undo the past,” Ramsdell said. “We have to find a way to move forward. The CAD is an economical way to actually do something about this problem.”

South Port Marine is a good example of how the cost of even testing, much less the disposal, can stymie private dredging efforts. The 170-slip South Portland marina had spent $24,000 on permits to start a dredge that would allow the company to keep berthing and servicing its larger boats, but it balked when it learned that the environmental tests alone would cost about $65,000. With disposal costs included, its controller estimated it would cost the company up to $500,000 to restore its berths to their original depth.

But siting a CAD cell would be tricky. It can’t be dug in the federal shipping channel, which is dredged every 10 to 15 years. Only certain kinds of ocean floor would support such a hole, ruling out areas where walls would simply slide down during the excavation, and ledge, which would require extensive blasting. Project officials would also need to avoid power lines, bird foraging sites, aquaculture beds, popular recreational boating areas, beaches and, perhaps most importantly in Maine, lobster fishing grounds.

In 2009, when federal officials were planning the dredge that wrapped up in 2014, the cities, the harbor commission and local nonprofits formed a working group to consider how to dredge between the wharves and piers, and begin the process of finding a suitable location for a CAD disposal site. At the time, the group settled on three sites – in the turning basin of the Fore River near Merrill Marine Terminal, by Fort Allen near the river mouth, and near Fort Gorges – but all turned out to be problematic. Only a modified version of the turning basin proposal remains in the running. Stantec is examining four potential sites.

The latest iteration of the work group, whose meetings are open to the public, met last month to solicit suggestions for other possible CAD locations, and engineers are now considering several of those proposals to see if they warrant additional review.

A THREAT TO WORKING WATERFRONT

The wharf owners are hopeful that the two grants will accomplish their goals of getting the necessary permits to dredge between the wharves and build a CAD cell to hold the tainted soils.

It’s not just Poole, with his 15 marine business tenants, including a chandlery, and another 15 to 20 lobstermen who tie up at Union Wharf, who now can’t conduct business during low tide, but also Widgery Wharf, whose owner, Peter Kelly, says he has lost 25 percent of his wharf space because of a lack of water depth. Kelly won’t build his $1 million machine shop and lobster pound until he can get it back. The owner of Sturdivant’s Wharf is known along the waterfront to have lost the most berthing space to sedimentation.

“We are a mature urban harbor,” said Portland’s waterfront coordinator, Bill Needelman. “In the 19th century, oceangoing schooners could pull right up to Commercial Street, but now many of the heads of the piers turn into mudflats at low tide. A lobster boat needs 2 or 3 feet at low tide, a ferry boat 7 to 10 (feet) and a large herring vessel as much as 15 feet.

“There are compelling environmental arguments to remove these contaminated soils, but the economic ones are overwhelming. If we don’t get some of that water depth back, the wharves will lose money, they won’t be able to make necessary repairs and the working waterfront, with all of its jobs, will disappear.”

Source: Portland Press Herald