By Nate Jones

Staff Writer 

 This summer the University of Maine’s Professor of Marine Studies and Quaternary and Climate Studies Dan Belknap will have his eye on the weather for a calm, quiet day to take a boat ride in Portland Harbor. Rather than packing lures or fishing rods, Belknap will bring  nearly $250,000 in seismic reflection and side-scan sonar equipment to help him find possible locations to dig a hole up to 80-foot deep in the ocean floor. 

“We can see rock, gravel, mud, shipwrecks and even lobster traps,” Belknap said of his high tech hardware. 

The hole will be for a Confined Aquatic Disposal (CAD) cell, and could be used to dispose of contaminated spoils created by a harbor-wide dredging project in upcoming years, South Portland Transportation and Waterfront Director Tom Meyers said. 

On April 23 the South Portland City Council unanimously approved the acceptance of an $11,500 Shore and Harbor Technical Assistance Grant from the Maine State Planning Office to fund the mapping project. More than $4,200 will come from the city’s street pier capital reserve account. Funding for the account is generated from fees collected at the small boating facility next to the Salt Water Grill restaurant.

“I’m all for regionalization,” Councilor Tom Blake said. “But can Portland pick up some of the tab?”

Meyers said he believed South Portland commercial waterfront property owners would benefit from the CAD project most directly by saving on costs for soil contamination analysis, which could cost private pier owners upwards of $80,000.

“We have taken the lead as a municipal member of the Waterfront Alliance to sponsor and shepherd this project,” Meyers said. “In this case, the city is also a potential beneficiary of the project. It’s reasonable for us to come up with some of the local match.”

 “We’re just talking about breaking some ice and moving forward,” Councilor Claude Morgan said.

Other alternatives for disposing of dredge spoils include offshore dumping or bringing the material on shore to be processed. 

Although possibly less expensive than the cost of digging a CAD cell, Meyers said offshore disposal would most likely not be an option for the dredging project as most of the material is likely to possess harmful contaminants.

“The expectation is that often, and not at the cause of the pier owners, the material has been contaminated,” he said. “It’s the ‘catch-22’ of dredging. Who wants to spend $80,000 to find out you can’t take [the dredge spoils] anywhere.”

Bringing contaminated material to onshore waste disposal sites would be “astronomically expensive,” and most likely eliminate the feasibility of dredging at all, Meyers said.

“[CAD cells are] kind of creative,” he said. “You leave the contaminated material in the water and put it somewhere it can be contained.”

As part of what Meyers called a CAD cell “perk test,” Belknap and his team will use a “Boomer” sonar device to analyze sediments up to 140 feet below the ocean floor to determine if there is an area of the harbor appropriote for the dig.

“We’re going to make sure we’re not going to hit bedrock, shipwrecks or any other archeological artifacts,” Belknap said. 

Councilor Maxine Beecher said she was concerned about harming lobsters and possibly affecting the local fishing industry while digging a CAD cell. Meyers said if a proper site is located for the CAD and lobsters are present there, the project would include a lobster relocation program similar to the one implemented during maintenance dredges of the federal ship channel in recent years.

Meyers said since most of the South Portland side of the harbor is ledge, as was made evident by the underwater blasting project required to dredge the Gulf Oil Pier last winter, the most likely spot for the CAD cell would be closer to a corner of “Anchorage A” by Pamroy Rock and Fish Point on the Portland side of the Fore River. 

“We know it’s already fairly deep where the shipyard used to be,” he said. 

Belknap said most of the harbor could be mapped in a single day and it would only take several more to analyze the data collected. 

“The cost is more about having the [the equipment] and the experience we bring to the project,” he said. 

Meyers said CAD cells currently exist in other major ports along the east coast, and have been proven a “well accepted and environmentally sound method of disposal.”

“This is something we have to do to keep the port as commercial as it is,” Morgan said. “The harbor is the lifeblood of the two cities.”