Bethpage Water District Blog

Monday, January 14, 2019

What is an aquifer?

    An aquifer is an underground layer of rock or unconsolidated material such as sand or gravel. It is saturated with fresh water and that water can be extracted using a well pump.

    On Long Island we have 3 aquifers, the Upper Glacial Aquifer, the Magothy Aquifer and the Lloyd Aquifer and these were formed during the ice age. The Magothy Aquifer supplies 90% of the waterused in Nassau County and is the source of all Bethpage’s wells. It is approximately 1100 feet deep at the lowest point under Bethpage and the water we extract can be over 100 years old.

    Our aquifers are some of the most plentiful in the country and it is estimated that they contain 90 trillion gallons of water. The Lloyd aquifer is 1800 feet below the surface and it is protected from the Magothy aquifer by an impermeable layer of clay. There is a New York Environmental Conservation law which established a moratorium on the use of water from this aquifer so it is protected for future generations. The only way the aquifers are continually replenished is through precipitation.

    The area covering Nassau County recharges 330 Million gallons per day from rain and snow into the aquifer system while an estimated 180 million gallons are pumped out from suppliers to provide drinking water.

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