A rocky ledge and a tree stump more than 40 feet below the surface of Long Island Sound are the most recent obstacles to completion of an electric cable between Connecticut and Long Island.
Shellfish spawning season ended Tuesday, allowing operators of the cable to resume dredging after a four-month hiatus.
A spokeswoman for Cross-Sound Cable Co., which is laying the 24-mile cable between New Haven and the former Shoreham power plant on Long Island, said construction is behind in one area about three-fourths of a mile out in a New Haven Harbor channel.
“We’re several weeks behind schedule, probably more than that now,” spokeswoman Rita Bowlby said Tuesday.
The company, a Westborough, Mass.-based subsidiary of energy giant Hydro-Quebec, is operating under the authority of permits issued by the U.S. Army Corps of Engineers and state Department of Environmental Protection. Those permits prohibited work during shellfish spawning season.
The cable must be buried at least 48 feet below the sound’s surface and 6 feet below the seabed. Work is nearly complete except for one area where the company has hit a snag, she said.
Work crews came upon a rocky area and a tree stump that is between 42 and 44 feet below the water level, hindering efforts to bury the cable to the required depth, she said.
The discovery of the tree stump was a “big surprise,” Bowlby said. “I don’t know where that came from.”
Work crews discovered the rock ledge during surveying in early June after laying and burying the cable, she said.
“It was a big surprise to discover what we hit,” she said.
Michael Grzywinski, an environmental analyst at the DEP, said agency officials met with Cross-Sound Cable officials in early September, requesting a plan on how the cable will be buried.
Cross-Sound Cable will not seek a revision to its permit, Bowlby said.
The company on Wednesday or Thursday expects to receive responses to work specifications for six areas and is surveying in the area where it has not reached the required 48-foot depth.
Workers are taking core samples of rock 48 feet deep in several locations. Weather-related delays also could drag out the project, Bowlby said.
Officials of the Long Island Power Authority say they need the 330-megwatt cable to alleviate possible power shortages on the island. State Attorney General Richard Blumenthal has environmental concerns about the project and has questioned whether Connecticut consumers would benefit.