Running Dry

Money is pouring in — large amounts of federal and state dollars — for sewer expansion in Suffolk County. The aim is to do sewering to offset the leaching of nitrogen into groundwater and protect water quality.

However, what about water quantity?

Most, although not all, of the sewer expansion plans that include western and central Suffolk and the East End involve sending wastewater through outfall pipes into surrounding bays and also into the Atlantic Ocean.

Suffolk County’s biggest outfall pipe, extending 4.2 miles into the Atlantic from the county’s Bergen Point Wastewater Treatment Plant in West Babylon, is designed to discharge 30 million gallons of wastewater a day into the ocean. There are smaller outfall pipes all over the county.

But outfall causes a depletion of the quantity of water in the aquifers on which Suffolk County and the rest of Long Island depends, emphasizes Long Island naturalist John Turner, conservation policy advocate for the Seatuck Environmental Association in Islip and former director of Brookhaven Town’s Department of Environmental Protection. He was legislative director of the New York State Water Resource Commission. He has championed treatment and reuse of wastewater to help preserve the underground aquifers.

Sitting between the Atlantic Ocean, the bays and Long Island Sound, the aquifers below Long Island constitute its sole source of potable water, its reservoir.

There is an interface between the freshwater of this reservoir and saltwater that surrounds us. Lowering the level of freshwater in the aquifers through outfall can — and has — resulted in saltwater intrusion and loss of potable water, and the lowering and drying up of streams, rivers and lakes.

Saltwater intrusion is a large part of how Brooklyn and Queens on the western portion of Long Island lost their potable water supply years ago. They now must rely on the system of manmade reservoirs and pipes to bring water down from upstate.

Mr. Turner speaks of “the sandy aquifers that underlie Long Island. This layered system of water-saturated sand, silt, gravel and clay sits atop a basement of bedrock. … In the middle of Suffolk County, the aquifers, replenished only by rain and snowmelt, are about 1,000 feet deep, while they are shallower in Nassau County. These tiered sets of aquifers are our drinking water supply and the sole source for meeting all our water needs.

“Imagine,” he says, this reservoir “to be a balloon of a certain size, and due to pumping of water and coastal discharge of the wastewater the size of the balloon lessens. Some significant things happen.

“First, as the water table drops, the top of the balloon — the surface water bodies, such as streams, lakes and rivers — either dry up or are significantly diminished. Second, the salty water surrounding the island pushes landward in a process known as saltwater intrusion, contaminating the edges of the aquifer.”

Neighboring Nassau County has been hit by a lowering of its aquifers, because 85 percent of the county is sewered and all of its sewage treatment plants rely on outfall of wastewater into surrounding waterways. In Nassau County, lakes, ponds and streams, which are the “uppermost expression of the aquifer system, have dropped considerably,” Mr. Turner said; Hempstead Lake “is Hempstead Pond.”

Some 25 percent of Suffolk County is presently sewered. A model here for reuse of wastewater and aquifer replenishment arrived in 2016, when the Riverhead Sewage Treatment Plant began sending treated effluent to the county’s adjoining Indian Island Golf Course. This has meant nitrogen-laden wastewater “no longer finding its way into the marine environment” and causing algae blooms and other impacts.

There is also a drive in Suffolk County for conversions of the cesspools used in 75 percent of residences to “Innovative/Advanced Treatment Systems,” but at the current rate it will take “many decades,” says Mr. Turner, to convert a substantial number. “Water reuse can help reduce nitrogen inputs in a much shorter time frame.”

There’s national action on water reuse. An extensive article this month on the website Truthout.org details how wastewater is being turned “into a resource” in the U.S. It points to Orange County in California, “a world leader in water reuse,” using “advanced treatment” that also “saves massively on the cost of pumping Colorado River water from hundreds of miles away.”

And the piece includes Las Vegas, Nevada, with “a 12-mile-long channel that acts as the ‘kidneys’ of the environment, cleaning the water that runs through … by filtering out any harmful residues on its way back to Lake Mead.”

What about Suffolk County moving more aggressively on reuse?