THE SOUTH FORK'S AQUIFER SYSTEM
All of Long Island-from Queens to Montauk depends upon its groundwater for its drinking water. Over the course of the millions of years that Long Island was formed, three aquifers were laid down by the expansion and the recession of ice sheets during its reoccurring ice ages.
Think of Long Island's aquifers as a layer cake. The bottom of the cake is the bedrock. Above that is the Lloyd aquifer, the most ancient. Above that, a layer of clay, above that the Magothy aquifer, and above that the upper glacial aquifer. The hilly sections (moraine) that run down the spine of Long Island is the result of the last glaciation, and contains the "Upper Glacial Aquifer." Along the highest mounts of this spine is the water divide, where the waters separate and either flow north to the bays or south towards the ocean.
The Upper Glacial Aquifer has been contaminated in Nassau and western Suffolk, and they depend upon either the Magothy or Lloyd aquifer. On the South Fork, we have no Lloyd aquifer to speak of, and we rely on the Upper Glacial Aquifer.
All parts of the Upper Glacial Aquifer are not equal-some parts being better and more important as they are deeper and more voluminous than other parts as occurs under the hills of Noyac where the former Bridgehampton racetrack (now Golf at the Bridge) sits. These areas are known as "deep-water recharge" areas. Think of them as giant underground reservoirs. At 80 billion gallons, the area below the golf course is the biggest and best of the South Fork's aquifers-nothing else here approaches it in purity and size. Its freshwater lens is over 800 feet thick. By comparison, Napeague's lens is only 50 feet thick; Montauk's 80-120 feet thick.
Our soil is sandy, so the rain that falls percolates down into the soil and "recharges" the aquifer. The hilly sections of the moraine are known as "deep water recharge areas" as there is a deep vertical component to the recharge, as opposed to the more shallow horizontal movement of recharge in the non-hilly "outwash plains" like Bridgehampton. The protection of these "deep-water recharge" areas of the South Fork is of prime importance. Think of them as the headwaters of a stream that must be protected from degradation. The New York State Legislature has designated these deep-water recharge areas on Long Island as "Special Groundwater Protection Areas." The Towns of Southampton and East Hampton have "five" such designated areas.
Our sandy soil, while aiding rain to "recharge," it also allows contaminants to percolate down freely as well. Development and paving has reduced the South Fork's ability to recharge, so a great percentage of rain is lost to runoff instead.
For a variety of reasons-cesspools, the agricultural use of pesticides, landfill leachate, petroleum and solvents, salt water intrusion, golf courses, heavy iron content, toxic spills-the South Fork's water is already compromised in many regions. Regions that may or may not have access to public water. (And even some public wells are contaminated. Thousands of private and hundreds of public wells must be treated with expensive and elaborate carbon filtering systems. It will only get worse.)
Nassau and western Suffolk rely on the more ancient Magothy Aquifer sandwiched just below the Upper Glacial Aquifer because their Upper Glacial Aquifer has already been contaminated; while the bottommost aquifer and the oldest-the Lloyd-is used for drinking water in southwestern Nassau because the Upper Glacial Aquifer is contaminated and the sandwiched aquifer-the Magothy-has salt-water intrusion. When the Lloyd aquifer goes those people will be in deep trouble.
Now, there is a lesson to be learned here from what's transpiring to our west. Development, overuse, pollutants, salt-water intrusion is destroying these aquifers. The Towns of Southampton and East Hampton should have formulated and implemented a Master Plan to protect and manage our fragile water resources years ago. They must act now, even though, by their procrastination they have, to a large degree, let the horse out of the barn.
"SPECIAL GROUNDWATER PROTECTION AREA" (SGPA)
HYDROLOGIC CYCLE
MAP (from USGS) pontentiometric/water altitude map gives elevation of fresh water lens in Upper Glacial Aquifer
 South Fork Groundwater Task Force
PO BOX 2360 Sag Harbor, NY 11963
Phone/Fax: 631 - 725 - 6200
Site By: Hamptons Online
|
|
|
