Fish-shaped Long Island, New York, is underlain by aquifers that are its sole source of drinking water. Photo courtesy of NASA/Wikimedia Commons.

Last week, the conservation organization American Rivers released its annual list of the nation’s most-endangered rivers.

I got to thinking, what if we had a sister list of most-endangered aquifers?

After all, water from underground meets 20 percent of U.S. water demand for drinking, crop irrigation and everything else. It also provides the base flows that keep many rivers and streams from drying up during the summer months.

So groundwater is crucial to our economies and ecosystems, yet it’s out of sight – and usually out of mind, as well.

Which is why a most-endangered aquifers list might help.

On such a list I would name the Ogallala Aquifer beneath the Great Plains, which supplies 27 percent of the nation’s irrigated farmland and has undergone decades of depletion. I would include California’s Central Valley aquifers, which are greatly over-pumped to grow the nation’s fruits and vegetables.

I would add coastal aquifers in Florida and the Carolinas, which are threatened by the intrusion of seawater. In some areas, heavy pumping from those aquifers has reversed the hydraulic gradient: instead of groundwater flowing out to sea, ocean water moves in, polluting fresh drinking water with salt.

And then there’s the groundwater I sipped for seventeen years while growing up on New York’s Long Island. For most of that time, all I knew was that our household water came from the big water tower elevated high above our community. I didn’t know that the source of water for our backyard wading pool, Saturday night baths and summer lemonade was beneath my feet.

But it was, and that made our water vulnerable to so many things we Long Islanders did on the land above it – from applying fertilizers to dumping waste products to paving over wetlands and woodlands. All that and more could damage the quality of the water we bathed in and drank. And it did.

Today, 3 million people call Long Island home. Some 80 percent of Nassau County, where I grew up, is developed. Most of the wetlands and open space are gone. But the sole source of drinking water remains the layered aquifers beneath the fish-shaped island.

In a wonderful new video, New York-based GRACE Communications Foundation lays out the unique challenges Long Islanders face in safeguarding their drinking water.

“As important as clean water is to economic health, it’s even more important to human health,” GRACE program director Kyle Rabin reminds us in the video.

Among the solutions put forth – curbing fertilizer and pesticide use, responsibly disposing of pharmaceuticals and hazardous waste rather than flushing them down the drain, maintaining septic systems to reduce nitrogen pollution, and protecting open space to promote rainwater infiltration and aquifer recharge.

“We have no Plan B once our drinking water is gone,” warns Robert K. Sweeney with the New York State Assembly, who also appears in the video. “It’s up to us to make sure that this resource is available for the future.”

The video’s opening segment is a must-see: on-the-street Long Islanders answer where they think their drinking water comes from.

Have a look. Have a laugh. And learn about the precious waters beneath our feet, and what we can do together to protect them.

Originally published at National Geographic Newswatch