Published August 17. 2013 4:00AM
Old Lyme - Two rivers popular with kayakers, canoeists and boaters that are getting too shallow in some areas could be getting a dredging.
The town, with state funding in mind, is looking into whether dredging the Black Hall and Four Mile rivers, which spill into Long Island Sound, would be a solution to silting that is occurring in the rivers.
The Harbor Management Commission is proceeding to the next two phases of a three-phase feasibility study of the rivers' composition, environmental impacts of dredging, and if and how dredging could be suitable for the waterways. When the study is complete, the town would decided whether and how to proceed.
The two rivers, which are home to marinas and state boat launch ramps, are important for recreational activity and provide water access to many people both in town and across the state, commission Chairman Steven Ross said.
"These waterways were getting silted in and the access to Long Island Sound from them has become difficult, particularly at low tide," he said, explaining that the situation could only worsen with time.
Wrapping up a rope after docking a sun-dappled motorboat near the Black Hall Marina on a recent weekday afternoon, Greg Raducha of Old Lyme said "dredging would be the best thing."
"The tides in here move sandbars around. At low tide, you have to go slow," said Raducha, adding that his boat has been stuck in the river at times, forcing him to wait for the tide to come in. He said he began docking his boat at the Black Hall River because the Four Mile River needed dredging.
Boaters said the most difficult spot to navigate on the Black Hall River is where it approaches Long Island Sound.
"Mother Nature has changed this over the past eight years," said Jack Fairburn, on his motorboat as he gestured toward the river, beyond the marina, where it meets the Sound.
Fairburn, a teacher and longtime boater, said the Black Hall River has changed over the years. He recalled that near where the Black Hall approaches Long Island Sound, there was about another half-mile long "island" sandbar with a fairly deep channel nearby that a storm eventually washed away. He also said that mud flats are visible at low tide.
In 2012, residents approved funding for the study that the town would conduct with the help of $200,000 from the state Department of Transportation. After the $19,000 first phase neared completion, the Board of Selectmen gave the commission last week the go-ahead to work with the same firm - Madison-based Coastline Consulting - on the next two phases for about $64,000 total.
Town officials and consultants will now meet with DEEP and regulatory agencies to discuss a hydrographic study that will chart the depth of the rivers, Ross said.
The next phase entails studying the rivers' composition and proposing dredging methods, according to Ross. A marine biologist will inspect samples, taken from various locations in the waterways, for organisms. Consultants will determine the composition of the silt and how much could be removed. They also will study the best way to remove the material and if the silt could be reused to shore up any beach or marsh areas.
In recent years, the state allocated funding toward maintaining ports, according to Chuck Beck, the state Department of Transportation's maritime manager. For example, a 2011 bill provided up to $6 million for improvements to ports and marinas, including dredging. Recently, the state commissioned the Connecticut Deep Water Port Strategy Study to recommend plans for ports in New London, New Haven and Bridgeport.
Preliminary estimates indicate dredging could involve removing about 13,000 cubic yards of materials from the Black Hall River and 9,787 cubic yards from the Four Mile River, Ross said. If dredged, the channels would remain about as wide as they are now but would be deeper and slightly rerouted to naturally deeper areas, according to Ross.
"The Black Hall River channel will be 50 (feet) wide from the (Route) 156 bridge south to where the Back River (from the State Boat Launch on Smith Neck Road) intersects the Black Hall. From there the channel will widen to 100 (feet) to and into Long Island Sound," he wrote in an email. "The Four Mile River channel will be 30 (feet) wide from the marinas to the (railroad) bridge. It will then widen to 60 (feet) into Long Island Sound."
The last phase of the study would require seeking approvals, including from the Department of Energy and Environmental Protection, he said. If the town decides to move forward with dredging in the future, the commission plans to dredge away from tidal wetlands and embankments in the most "environmentally sensitive" manner as possible, he said.
Ross said the commission aims to finish the study by the end of next year.