July 19, 2017

Water Views


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I have wonderful childhood memories of flounder fishing with my uncles in Montauk. I can remember catching my first flounder (it felt like I caught a rubber boot) and standing up in the boat shouting, "I caught a flounder!" As the other fishermen began looking my way, my uncles tried to explain the virtues of silence.

The beginning of this exciting adventure began on the "Long Island Parkway" and eventually reached open country where on both sides of the road were miles and miles of potato and duck farms. Occasional homes and villages would appear, but back then the population in Suffolk County was a quarter million. Today it is a million and a half.

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Combined with the six-fold increase in population, two additional factors: (1) minimal wastewater treatment, and (2) sandy soils, have inevitably resulted in water pollution, associated algal blooms, inedible shellfish, a decline in the flounder fishery and closed beaches. As the result of our public concern with the effects of groundwater pollution we now have excellent information and maps describing the current situation. The Nature Conservancy's map below quite graphically depicts the extent and effects of groundwater pollution in the East End.

To understand our current predicament, first we must understand Long Island's unique geography. Long Island is the result of retreating glaciers 21,000 years ago that left, in essence, a giant sandbar protruding out in the Atlantic Ocean. This sand bar, with two parallel ridges running the length of the island, has provided both an incredible ocean shoreline and a huge pile of sand and gravel that collects rainwater in three separate aquifers.

These aquifers are the only source of groundwater on which the entire population of Long Island depends. This pure water allowed the early settlers to hand dig wells for their homes and farms and has been the essential resource that has allowed Suffolk County to grow.

Early settlers relied on outhouses and until the invention of the flush toilet this was the only disposal option for human waste. With the arrival of the flush toilet and internal plumbing, rural homes could install septic tanks with leach fields.

Originally designed by the USDA in 1871 for homesteads of 160 acres, the septic tank separated solids from wastewater and allowed the settled organic compounds to be anaerobically digested in the tank. The liquid portion, primarily water and urine, flowed into a leach field - a trench dug in the sandy soil with rocks placed in the bottom to assist with drainage. Although providing better wastewater treatment than outhouses, septic tanks and leach fields provide only limited treatment and removal of nitrogen and other pollutants found in wastewater. The sandy soils of Suffolk County allowed the septic tank effluent with all of its pollutants to rapidly drain into the aquifer. Bacteria in the soil provide some treatment returning about 25 percent of the nitrogen to the atmosphere, but the rest moves with the ground water to the edges of the island.

Despite the massive development of Long Island since 1950, the primary form of residential wastewater treatment still relies on 150-year-old technology. Today at least 112,500,000 gallons of wastewater per day (including 42,900 lbs./day =7829 tons/yr. of nitrogen and 23,100 lbs./day of phosphorus) is flushed with limited treatment into the aquifer.

To put this in perspective, we could grow 156,582 acres of corn (an area slightly more than one quarter of Suffolk County) with the nutrients contained in this wastewater. In addition to human waste, nitrogen and phosphorus flows from agricultural fertilizers, residential landscape and garden fertilizers, and industrial wastewater.

At the edges of the island, where groundwater mixes with salt water, green plants (in the form of algae and sea grass) take advantage of this essential nutrient. Unfortunately, the most adventitious forms of algae are also toxic.

The summertime water demands by the forest, lawns and gardens (evapotranspiration) reduce the effects of rainwater dilution on the groundwater increasing the nitrogen concentrations. As the algae grow and die, the dead algae place an oxygen demand on the water creating regions of low oxygen (hypoxia) where clams, fish, oysters, crabs will suffocate and unless they can escape, die. The coastal regions of the island are the nurseries for the fisheries, and as these areas become impacted by toxic blooms or hypoxia, so goes the fishery. (See Nature Conservancy above)

If the groundwater pollution continues, then what happens to the shellfish, fish, and fowl? Summers at the beach? What about taking your children flounder fishing?

The good news is that there are solutions that can reverse a couple of hundred years of abuse of the groundwater. They can be implemented over time, house-by-house, village-by-village as political will and financial resources become available. Future articles will describe some solutions that have been adopted by similar communities. We can fix it. Maybe its time for all to stand up and shout "Time to clean it up!"

Michael Ogden, PE (Civil Engineer) is a fifth generation New Yorker, and ex flounder fishermen.

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