The eastern basin of Long Island Sound ranks high for water quality, as it benefits from lower population density in the region and natural tidal flushing from the ocean, according to the 2020 Long Island Sound Report Card released this past week by Save the Sound.
The eastern basin earned an “A+” grading in the water quality report card, which is released every two years, while western parts of the Sound, which face higher population density and less natural flushing from the ocean, fared worse, said Peter Linderoth, director of water quality for Save the Sound.
This year, the report not only graded the open water of the Sound, but also the water quality of 50 bays and bay segments to call attention to high-priority areas for restoration efforts, as well as areas that deserve continued protection, he said.
Southeastern Connecticut is home to some of the highest graded locations in the state — Outer Stonington Harbor, Mystic Harbor, Outer Niantic River and Inner Stonington Harbor — but also one of the lowest, with Wequetequock Cove receiving a “D-” grade.
The grades for the region are as follows:
Wequetequock Cove: D-
Mystic River: B
Mystic Harbor: A
Inner Stonington Harbor: A-
Outer Stonington Harbor: A
Alewife Cove: B
Inner Niantic River: B
Outer Niantic River: A-
Connecticut River: B+
The water quality in neighboring Long Island Sound doesn’t predict the water quality in a single bay, because the “shallow bays are impacted by the human-sourced pollution flowing in with their local freshwater,” said Jamie Vaudrey, assistant research professor in the Department of Marine Sciences at the University of Connecticut and one of the science advisers on the Unified Water Study working on the grading system and the report card.
“When coupled with poor tidal flushing due to restrictions like train bridges and sand bars, the water quality in these bays can be worse than in the main stem of the Sound,” she said. “This is evidenced by the poor grade we see in Wequetequock Cove, located in the Eastern Sound.”
Overall, the bays in the eastern Sound scored “quite well, reflecting the lower population density and greater amount of undeveloped space in this end of the Sound,” Vaudrey said.
However, the overall report of 50 bays and bay segments in Long Island Sound found that less than half of them earned a B or higher grade, and the report raises concerns “about the current ecological health of local bays and their resilience in the face of warming trends and ongoing pollution from Sound communities,” according to a news release from Save the Sound.
Save the Sound also points out in the release that 48% received poor grades for dissolved oxygen levels: low levels can result in fish and marine life die-offs.
Linderoth said climate change and excess nitrogen are major challenges to water quality. People can learn more about each bay at soundhealthexplorer.org and see action steps they can take.
The Wequetequock Cove…