For over a year now, Prof. Charles Flagg and his research team from SOMAS (The Stony Brook School of Marine and Atmospheric Sciences) have been monitoring the breach of Fire Island at Bellport Bay, also known as The New Inlet, or The Old Inlet, since from the late 1700’s until 1826 there was a navigable inlet near this location.
This report, their tenth, available here Inlet_Report_10 in its entirety, discusses both how the breach has evolved and mutated, while remaining stable over all in terms of its flow and its influence on water quality in The Great South Bay.  Bellport Bay — and not much more than that — continues to benefit greatly from the influx of fresh clean ocean water and the outflow of nitrogen rich, oxygen depleted water.
So as we come to the end of 2013, what is SOMAS’ assessment of the breach?
At this point the inlet has survived winter storms and summer doldrums – neither getting so large as to irrevocably change the character of Great South Bay nor filling with sand and closing on its own. The breach seems to have developed into a small, semi-stable inlet that has not endangered the nearby communities while it has markedly reduced the residence time of the waters within the relatively remote Bellport Bay area. (Remote in the sense of being far from Fire Island Inlet.) The improvement in water quality is quite evident in this eastern region and there are now fish species and sizes that have not been seen here in decades. It is much too early to say that the ecology of the area has recovered, it will take years for the sea grass beds and hard clams to re-establish themselves. And it is important to keep an eye on this evolving system, as we and others are doing, to support science-based decision-making. But it does appear at this point that the gamble the Park Service made by leaving open the breach in the wilderness area, has paid off.
In other words, the breach has been an unalloyed boon to Bellport Bay, but it will take time to see its full environmental benefit for the area.
Given our experience here, maybe what The Great South Bay REALLY needs is more inlets, especially in the western part, where the algal blooms have really taken their toll.