Pictured Above: Peconic Green Growth’s map of East Marion. Groundwater from the areas in pink reach the adjacent surface waters in zero to two years.
Long Islanders have long taken our drinking water, like our septic systems, for granted, in part because we’ve been lucky, and in part because they are both buried under our feet.
We’re lucky to have the relatively easy-to-access Upper Glacial Aquifer beneath the sandy soils left behind here by the retreating Wisconsin glacier 11,000 years ago. Water percolates and is filtered through sand and gravel glacial deposits into this aquifer, which is easy to tap into. While much of the western United States is facing the well-publicized exposure of the faults of its dependence on the Colorado River, our dependance on our aquifer is something we don’t pay enough attention to.
This issue is particularly critical at the tip of this island, where an ever smaller lens of fresh water sits beneath the thin spits of land jutting out into Block Island Sound. It stands to reason that the amount of ground beneath our feet is correlated to how much groundwater is beneath that ground. Shelter Islanders have known this for years, and this is why irrigation is prohibited on Shelter Island. It’s time for the mainland government, particularly in sensitive areas like East Marion, to consider regulation irrigation.
What we do have in most places on the mainland that Shelter Islanders don’t have is good access to public drinking water infrastructure, which allows plentiful water to flow from areas of abundant water to areas of greater need. While this solves an immediate problem, it does have one unfortunate drawback — it allows us to stave off thinking about how our water use is out of balance with the natural systems that provide us with the water.
Long Island has long had an ample supply of groundwater — it is estimated that the island’s aquifers contain between 65 trillion and 120 trillion gallons of water, which is recharged every year by 600 billion gallons of rain. In comparison, the Suffolk County Water Authority pumps just 70 billion gallons out of our aquifer each year.
But even though groundwater is plentiful here, its distribution is not even. Much of our public water on Long Island comes from wells far inland, both in the Central Pine Barrens and in areas close to the groundwater divide, the place at which groundwater is equidistant from and can flow toward more than one watershed.
On the groundwater divide on the North Fork, water can flow toward the Long Island Sound or it can flow toward the Peconic Bay. If this water was to move underground, unimpeded by human intervention, it would take years or generations for it to make its way to the bays. But our intervention sends that water straight through a network of pipes toward private homes that are mostly already clustered near the bays.
The wastewater that reenters the aquifer through our drains and irrigation systems does so much closer to the bays than where it was pumped, and has far much less time to be filtered by the slow process of moving through the ground before it reaches the bay. This is why it is so vital for people who live near the water to reduce the pollutants emanating from their properties, either by upgrading their cesspools or reducing the use of fertilizers and pesticides on their lawns.
Public water infrastructure is also limited by its capacity during times of peak use, particularly in smaller municipal water systems. Riverhead, which is dependent on a limited municipal public water system, is considering enacting irrigation regulations, after several years of voluntary irrigation regulations that have been largely ignored by residential consumers, and by the many large commercial users of water in the town. Now is the time to enact these regulations.
While rainwater readily percolates through the soil to recharge our aquifer, this gift comes with a big caveat. It is also easy to contaminate this water supply. What’s beneath our feet here is also what can wreak all kinds of cancers on our community, particularly on those of us still drinking from private wells, which have really become a relic of 20th Century infrastructure.
We are increasingly reliant on the Suffolk County Water Authority to clean and filter our water to the highest standards, including those being set on an ongoing basis as the newly recognized health risks of contaminants like perfluorinated compounds and 1,4 dioxane need to be mitigated. While it does cost a bundle to connect the last remaining houses with private wells to public water, this is a public health necessity.
In the past on Long Island, particularly in the far reaches of the East End, opposition to public water has gone hand-in-hand with opposition to development. Recent years have shown that development here is inevitable. How we guide that development, toward hamlet centers and away from open space, is going to be crucial to the resilience of our region in the years ahead so that this will continue to be a place where working families can live and drink clean water.