Saltwater intrusion is a constant threat to our water supply, either from a hurricane—Island Pond used to be fresh water, until it became brackish after the 1938 hurricane, making it a perfect environment for oyster farming—or from over-pumping, which could draw saltwater into our underground aquifer.
Another more recent threat, and a great concern for the water company, is the high level of nitrates, turbidity and algae growth that now exist in Middle Farms Pond. During the severe 1960s drought, water was transferred via temporary pipes and pumps to Barlow Pond for filtration and distribution into the Island’s water mains. During the 2016 drought, however, Middle Farms Pond water was too contaminated for the filtration plant to process.
Although the causes are not yet clear, years of boating, fishing and swimming, plus potential wildlife, septic and fertilizer contamination are likely contributing factors to pollution at Middle Farms Pond. Beginning in 2018, the water company began prohibiting public use of the pond. This action will facilitate testing to identify the causes of contamination.
Zebra mussels. U.S. Fish & Wildlife Service Photo
Closing Middle Farms Pond will also address another threat: the potential introduction of the invasive Zebra mussel. This fingernail-size mussel can attach itself to a boat that is used in another body of water and then used in Middle Farms Pond. There would be no way to eradicate the bivalve from the pond once that happens.
By removing sources of contamination and avoiding mussel infestation, the pond could have potable water within five years.
The pond’s closure coincides with the water company’s multi-year plan to modernize Fishers Island’s aging water infrastructure. These projects include restoring the third Middle Farms well, building a new filtration plant for well water, installing water meters that can be read remotely, renovating or replacing the surface water treatment plant at Barlow Pond and, over time, replacing parts of the Island’s water mains and control valves.
The Island’s fresh water delivery system was constructed in the early 1900s to provide potable water and fire protection for the Island. Water is delivered through 22 miles of mostly unlined cast iron mains, and the 500,000-gallon Chocomount “Top of the World” Reservoir maintains system pressure and provides water storage for the fire department.
Fishers Island ponds.
Most of the surface of Fishers Island is, in effect, a “recharge area” for our pockets of ground water and the watersheds of our reservoir ponds. This means that any substance used or disposed of on the surface of the Island or in subsurface septic systems is likely to eventually find its way into the Island’s water supply.