Housatonic River dredging project completed

The Housatonic River is 149 miles long and originates from two branches in the Berkshires. Over the past 36 years, since the river was last dredged, hundreds of thousands of cubic yards of eroded sediment have flowed down river, much of it deposited in the lower reaches between Milford and Stratford, hindering boat navigation.

A recently completed dredging project cleared up much of that sediment: Currituck, a small dredge hopper, cleared 63,000 cubic yards of sediment during a month-long project that ended Dec. 1, said Bill Rock, chairman of the Stratford Waterfront and Harbor Management Commission (SWHMC). The SWHMC worked with the U.S. Army Corps of Engineers to get the job done.

“Basically, we gave the river an angioplasty,” Rock said.

The project was a success, he added, but cautioned that regular maintenance must follow.

Two areas in the channel between Stratford and Milford were dredged: The mouth of the river beyond the breakwater, and the bend from navigation buoy 19 to just south of the Washington Bridge into Devon.

The mouth of the river was dredged from depths of 8 and 9 feet to 15 to 17 feet. Some areas that were two and three feet to the center of the channel were dredged to 9 to 12 feet and in excess of 14 to 18 feet on the other side of the channel.

Other depths from the mouth to the bridge are at 18 feet deep.

Silt was essentially vacuumed off the river’s bed by the Currituck, a boat owned by the Army Corps of Engineers. The material was dropped into Long Island Sound about one-half mile off Long Beach. Incoming tides will help the sand “nourish” the beach at Long Beach, Rock said.

Earlier federal and state tests showed the silt to be pure and free of pollutants, he added.

The last time the river was dredged was 1976 when the Corps of Engineers hydraulically removed 215,000 cubic yards of sand from the river bottom and placed it on Short Beach. At that time, the federal channel from the Route One Bridge to the end of the breakwater at the mouth of the river was dredged to a depth of 18 feet, at mean low water, by 200 feet wide.

Times change, and Rock said the river didn’t need to be 18 feet deep anymore: 14 feet would suffice.

“The original, congressionally authorized channel depth of 18 feet was necessary to allow bottom clearance for barges that took fuel oil to the Devon power plant just upriver of the Railroad Bridge,” Rock wrote in a summary of the project. “By the 1990s the river had already silted in so much that there were frequent groundings of these barges.”

That is when the SWHMC, a volunteer commission in Stratford, began its efforts to have the river dredged, a process that would take some 13 years. By the time the project began, portions of the river that were previously 18 feet deep were as shallow as two and three feet deep right up to the center of the channel.

When the power plant switched fuels and barges were no longer needed to transport oil, the Housatonic was down-graded in terms of its dredging priority compared to other Connecticut ports and harbors.

The SWHMC, however, believed the river had become a hazard for recreational boats and that water dependent businesses that support the Stratford economy required a passable channel. So dredging was still paramount.

The original project called for dredging to a depth of 18 feet with a width of 200 feet, requiring the removal of 650,000 cubic yards of sand at a cost of $13.5 million dollars.

“By surveying the sizes of the approximately 2,000 vessels that currently use the channel annually, and those likely to use it in the future, it was determined that a depth of 14 feet would suffice,” Rock said.

The final cost was $750,000, paid by state bonds secured by the Department of Transportation.

The project is significant for several reasons, according to a report: It was done at a drastically reduced cost than originally projected, and it probably would not have been done if not for the determination of a volunteer commission that would not accept the idea that the project was insurmountable.

“By designing the project the way the SWHMC and Corps of Engineers did, it will not only provide the opportunity for follow-up maintenance dredging projects in future years, but stands as a model for other communities in Western Long Island Sound with harbors  fitting the criteria,” Rock said. “Thus the SWHMC has paved the way for similar projects in other Connecticut waterfront towns with harbors that need dredging and which can accommodate the Currituck.”