Bellport Bays’ Clean Water Passageway to the Ocean Endangered by Man

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By Katherine Wright

A 500-meter-wide pathway through Fire Island that brings clean ocean water to Bellport Bay could be closing due to human activity, according to Charles Flagg, a professor at Stony Brook University’s School of Marine and Atmospheric Sciences, who has been studying the breach since it first opened.

The closing is likely due to accrual of sand washed down the coastline from Moriches Inlet, where it was added in 2016 and 2017 to stabilize the dunes, Flagg said.

“They put one hell of a lot of sand there and since people put it there nature is going to start reworking,” Flagg said. “A lot of the sand that we are seeing here probably originated in some of that rebuilding,” he said. “That’s the thing about rebuilding. You put sand here and it definitely an ephemeral creature, its going pick up its bags and move.”

If this trend continues and the breach shuts, he said, the bay’s clean water supply could be cut off, potentially devastating the bay’s newly prospering ecosystem.

“That would be a sad day for me, and many others in our community,” Thomas Schultz, a Bellport Village resident, said. “If the inlet closes naturally, Bellport Bay will quickly revert to its original state.”

Super Storm Sandy carved three holes through Fire Island when it hit New York on October 29th 2012. Due to the increased risk of flooding on the mainland, the U.S. Army Corps of Engineers quickly plugged the holes at Cupsogue County Park and Smith Point County Park. But the gap into Bellport Bay, which lies in Fire Island National Park, was left open.

“The National Park Service policy is to let natural processes occur as they will,” Kaetlyn Jackson, Fire Island National Seashore Park Planner, said. “We let nature take its course, that is why the breach stayed open.”

The park closely monitors the breach and its impact on the local area. And while there has been no significant increase in water levels in the bay, or risk of flooding, the breach is influencing the local ecosystem. Twice a day the ocean “flushes” in and out of the bay, providing a source of clean water that, which over the last five years, has enabled marine life to prosper.

“The species richness has increased and their diversity has increased,” Jackson said.

For example, blue mussels have been spotted in the southern part of Bellport Bay close to the breach where the ocean cools the bay’s water, Gregg Rivara, an aquaculture specialist at Cornell Cooperative Extension, said. While the lady crab, which like high salinity waters, are flourishing, Jackson said.

“The inlet has allowed us to see what the bay looked like a hundred years ago and what it could look like moving forward,” Schultz, who cofounded the organization Friends of Bellport Bay with the aim of improving the water of Bellport’s coast, said. “It’s given us a great opportunity to understand that we don’t have to live along a polluted body of water.”

Bellport Bay sits near the eastern end of Great South Bay, a series of lagoons that stretch nearly 50 miles along Long Island’s south shore from Far Rockaway in the west to Southampton in the east.

Nitrogen and toxins seep into Great South Bay from leaky septic tanks and lawn fertilizers, amongst other things, polluting the water and triggering algal blooms. This problem was particularly acute in Bellport Bay, which, before Sandy opened up the breach, had no direct access to the sea.

“I refer to that body of water as a low grade septic system,” Schultz said. “The lagoons could be as beautiful and clear as the lagoons in the Bahamas, if it weren’t for the decades of pollution.”
Then Super Storm Sandy happened.

“Having this access to the ocean has cleaned out [Bellport Bay], not completely, but to a large extent,” Flagg said. “It has improved water quality, and reduced the intensity of the brown tides.”
Data collected by Flagg, and his colleagues, show that oxygen and salinity levels in the water have both increased, making the water more hospital to marine life.

“The inner lagoon has become a great breeding ground for many species of fish,” Schultz said. The numbers of flounder, fluke, and striped bass are all up.

A raised sand bank developed this summer in the middle of the breach through Fire island into Bellport Bay.

A raised sand bank developed this summer in the middle of the breach through Fire island into Bellport Bay.

But that could all change when the breach closes.

“If the inlet closed up, the blue mussels would probably die off,” Rivara said. “It would get too warm for them.”

The closing of the breach will likely return water salinity to its previous lower level and increase stagnancy of the bay. “It would take longer for the water to flush in and out of the two inlets at Moriches and Fire Island,” Jackson said.

Flagg and Jackson both expect the breach to close in the foreseeable future, although neither would hazard a guess as to when.

Flagg flies over the breach once a month in his Piper Super Cub to snap the changing landscape and this summer he noticed that the opening had narrowed. “It looked like [the breach] was heading towards closure,” Flagg said.

However, the breach has widened since. “Jose parked offshore for a couple of days and it created really large waves that chewed away the sand…it set the clock back a bit.”

About the Author

Katherine Wright
Katherine Wright
Katherine is a science writer and journal editor working for the American Physical Society in Long Island, N.Y. She is a part-time journalism graduate student at Stony Brook University.