Leeds Pond, Battleground


Runoff a threat to overall health of delicate ecosystem

A view of the outflow into Manahasset Bay. (Photo by Daniel Greilsheimer)

The Village of Plandome Manor has become the most recent local battleground in the fight between development and environmental protection. A recent Board of Zoning appeals meeting saw a request from 1362 Plandome Road LLC, which is directly on Leeds Pond, for the placement of 500 cubic yards of site fill which exceeds the maximum allowable amount of 50 cubic yards as set forth in Village Code.

Leeds Pond, a 22-acre fresh body of water in Plandome Manor, is the main collection for more than 2000 acres of watershed, and it outflows into Manhasset Bay. More than 150 species of birds have been documented at the pond. It is adjacent to the Leeds Pond Preserve, which is the home of the Science Museum of Long Island. The edge of this pond is already mostly developed, with homes extending nearly all the way around the approximately 4500 feet of shoreline.

A view of the disputed construction.
(Rendering from Google Earth)

Barbara Donno, Mayor of Plandome Manor, released a letter in response to a flyer against the fill that was being circulated ahead of the meeting. She states that “The BZA application pertains solely to the amount of fill placed on a piece of property. There is no work being proposed that affects Leeds Pond whatsoever. Furthermore, it is essential to note that the building project in progress has received full approval from the New York State Department of Environmental Conservation (DEC). The DEC, being an authoritative regulatory body on wetlands like Leeds Pond, has evaluated and granted their consent for the project, ensuring compliance with all relevant state and village codes. All necessary precautions and measures have been taken to adhere to the guidelines and regulations set forth by the DEC, ensuring the environmental sustainability and integrity of the area.”

However, Christopher Gobler, who is a distinguished SUNY professor at Stony Brook University, director of the New York State Center for clean water technology and an endowed chair within the School of Marine and Atmospheric Sciences at Stony Brook, spoke at the BZA meeting to address concerns about nitrogen and other contaminants this amount of fill could deposit into Leeds Pond.

Gobler and his team tested the water in Leeds Pond in May. “We measured the levels of nitrogen and phosphorus in the pond and found there were many fold levels higher than the levels the EPA would recommend for either a freshwater body or marine water body. My research is studying something called harmful algal blooms and looking at algae in general. So we measured the total levels of algae and found that they were significantly above what the EPA would recommend for freshwater or marine water body. We also looked at the types of algae in the water and found significant levels of what we call blue green algae. Those algae are of concern because they make biotoxins, which can be harmful to humans or to wildlife. We also measured levels of two types of toxins in the water, microcystin which is a gastrointestinal toxin, and Saxitoxin, which is a neurotoxin, and we found those toxins in the pond,” Gobler said in a phone interview about his presentation.

It is important to note that these levels tend to increase as the weather warms, so as the summer progresses, the condition of the pond is expected to deteriorate. “Typically, blue green algae and the toxins they produce are at their worst levels in summer and into late summer into fall. So everything we found we anticipate will worsen as we transition from spring into summer and then in the fall,” Gobler said.

Further development around the pond, and unchecked development in general, is of great concern. Soil contains both nitrogen and phosphorus which are naturally occurring. Additionally, runoff from lawns and other landscaped features like golf courses eventually ends up in water bodies and feeds the algae. Gobler said that “the blue green algae (blooms) are intensified by nutrients, specifically nitrogen and phosphorus, and that often happens in what we call a dose dependent manner, meaning the more nitrogen and phosphorus you add, the more intense those blooms become.”

A path forward for Leeds Pond, and freshwater bodies in Nassau County in general, takes into consideration the overall future of natural spaces, and how restoration and preservation benefit the community as a whole. Gobler worked closely with the DEC to develop a coastal management plan for Nassau called the Nine Element Plan. This plan called for a nitrogen reduction of 40 percent for Manhasset Bay, which is the outflow for Leeds Pond.

When asked about the importance of Leeds Pond in the overall watershed and ecosystem, Gobler stated, “I think the bottom line is that everything adds up. It is important and it has an influence on Manhasset Bay, and therefore an influence on Long Island Sound.”

To view the nine point plan for Nassau County’s water bodies, visit https://www.nassaucountyny.gov/5373/Nassau-County-9E-Plan.


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