Living in Long Island, our drinking water doesn’t come from lakes, rivers, or giant pipes bringing water from far away. Actually, the water comes from right below your feet! These are called aquifers.
What is an Aquifer?
An aquifer is like a giant underground sponge. They are composed of layers of sand, gravel, and rock that hold water. When it rains or snows, the water soaks into the ground, trickles down through the soil, and eventually fills up these aquifers. That water is known as groundwater: fresh, clean water used for drinking, irrigation, and more, all stored in aquifers!
The Aquifers of Long Island
Long Island has three main aquifers, sloped and stacked on top of each other. They have been forming for millions of years. In fact, the oldest and bottommost aquifer, the Lloyd Aquifer was formed when dinosaurs were still around! Here is some more about each one:
- Upper Glacial Aquifer – This is the top layer, just below the ground. It’s the youngest, formed during the last ice age 10-15 million years ago. Being closest to the surface, it is most vulnerable to pollution, but it’s still used in some areas.
- Magothy Aquifer – This is the biggest and most-used aquifer on Long Island. It is over 1000 feet thick, but protected by layers of clay and sand, helping to keep it cleaner. The sand and gravel was deposited during the Upper Cretaceous Period, 50-80 million years ago. (Fun Fact! This supplies over 90% of the water found in Nassau County, and ~50% of the water in Suffolk County.)
- Lloyd Aquifer – This is the oldest and deepest aquifer, with deposits from the Cretaceous Period and depths of 1,800 feet. This ancient aquifer is non-renewable on human timescales, so is protected for future generations of emergencies. (New York Environmental Conservation Law §15-1528).
How Does the Water Get to Us?
Water is pumped up from the aquifers by deep holes drilled into the ground, or wells. Water treatment plants then clean and test the water to make sure it’s safe to drink. After that, the water travels through pipes all the way to your faucet, your school, and even your garden hose.
Why Should We Care?
Because we depend on our aquifers for all of our drinking water, it’s super important to keep them clean. Polluted water from chemicals, garbage, oil, or even too much fertilizer can seep into the ground and harm the water we drink. Once aquifers get polluted, it’s really hard, and expensive, to clean them.
Fun Facts!
- Long Island’s groundwater formed during the last Ice Age, over 10,000 years ago!
- Around 2.8 million people on Long Island use aquifer water every day.
Some of the water we drink today might have fallen as rain hundreds of years ago!
What Can You Do?
- Never pour chemicals or paint down the drain or onto the ground.
- Use less water—every drop saved helps the aquifer last longer!
- Tell others what you learned! Protecting our water starts with being informed.
More Resources To Check Out!
Long Island: Where Does Our Water Come From?.
Our Long Island Aquifers: The Basics | Nassau Suffolk Water Commissioners Association (NSWCA)