Seatuck Litigation Statement

Conservation groups file lawsuit challenging Suffolk County’s inadequate review of proposed Nissequogue dam.

July 14, 2026

Seatuck has joined five other Long Island conservation organizations in filing suit against Suffolk County to challenge its deficient environmental review of the proposed new dam on the Nissequogue River in Blydenburgh County Park. 

This is not an action the organization took lightly; in fact, it is the first time Seatuck has ever engaged in litigation. It was a carefully made decision, after thorough, thoughtful deliberation. In the end, we were driven by a commitment to our mission to conserve Long Island wildlife, by a sense of urgency to restore centuries of damage to our waterways and reverse the decline of struggling species that depend on cold, free-flowing rivers, and by the call to take a stand against the wanton disregard for the laws that were put in place to protect the environment on which we all depend.

The suit alleges that in seeking to advance the new dam, the county failed to take a “hard look” at the project’s potential environmental impacts, as required by New York’s State Environmental Quality Review Act (SEQRA). Instead, the county determined – despite urging from NYSDEC and a coalition of twenty conservation organizations – that the proposal had no potential to cause significant adverse impacts on the environment and therefore only warranted a cursory analysis. 

Among a host of potential impacts that were ignored (see list below), the county failed to assess the environmental impacts of flooding two miles of river habitat and 120 acres of freshwater wetlands, where a robust natural restoration is underway and important new habitat is emerging for native birds, insects and other wildlife. 

The suit seeks to compel Suffolk County to complete a comprehensive Environmental Impact Study (EIS) as required by SEQRA for such projects. An EIS includes not only a detailed analysis of potential impacts, but also a review of alternatives and measures to mitigate impacts of the proposed dam. It also provides opportunities for meaningful public engagement to ensure all environmental impacts are addressed and minimized.

The Nissequogue River is one of the largest and most significant rivers on Long Island. The 2024 failure of the Stump Pond Dam represents a unique opportunity to reconnect the Nissequogue, and improve the ecological health of the river, Long Island Sound and the region’s coastal ecosystem.

Potential Adverse Impacts to the Environment from Proposed New Dam

The following is a partial list of the proposed dam’s potential adverse environmental impacts, all of which warrant a detailed analysis through an EIS, but were ignored or received only a cursory analysis as part of the county’s review:

1. Flooding two miles of riverine habitat – The proposed new dam would flood two miles of existing river habitat, which accounts for more than 25% of the non-tidal, free-flowing reaches of the Nissequogue River. The provides valuable habitat for species that rely cold-water habitat, including brook trout, New York’s only native stream-dwelling trout (and the state’s official freshwater fish).

2. Loss of freshwater wetlands from flooding – In addition to flooding the river, the new dam would flood 120 acres of “Class 1 wetlands”, which provide the most critical ecological and flood-protection benefits. More than 125 plant species have already been identified in these wetlands (74% of which are native), and the habitat has attracted a diversity of birds and other wildlife, including a dozen species that have never been confirmed in the park (e.g., Pectoral Sandpiper, Vesper Sparrow) and four dozen other species that have been recorded in high numbers since the dam failure (e.g., Least Sandpiper, Great Blue Heron).

3. Loss of freshwater wetlands from filling – Wetlands would also be directly destroyed by the construction of the dam and fish passage. To accommodate the more than two feet of additional heigh, the new dam will be wider than the old dam. This expanded footprint will come at the expense of existing wetlands, including forested wetlands on the downstream side of the dam.

4. Flooding of habitat for Atlantic White Cedar – The stumps that gave the former Stump Pond its name are Atlantic White Cedar; they’re remnants of a large cedar forest that once thrived along the river’s edge. With the dam gone, there is potential for this highly imperiled species–and the unique community it supports–to recolonize its former habitat.

5. Impeding wildlife movement – Dams block wildlife from moving freely within rivers and impede the migration of species (e.g., alewife) that move between rivers and marine waters as part of their life cycle. Fish passes can mitigate some of the harm, but only to a limited extent. Even when they work, warm-water ponds generate temperatures that reduce reproductive success and support species that increase predation, generally inhibiting native cold-water species from thriving.

6. Generating thermal pollution – The solar energy collected by the shallow pond would significantly increase water temperatures. As it flows downstream, this warm water would alter the natural temperature regime of the river, degrading habitat for brook trout, river herring and other cold-water-dependent species.

7. Removing mature trees – The proposed construction of the new dam would require the removal of approximately fifty large trees. This would permanently eliminate wildlife habitat and reduce the site’s overall capacity for carbon storage.

8. Raising groundwater levels – The proposed new dam would not only create a 100-acre pond, but also raise groundwater levels in the vicinity. This would restore the flooded basements and septic tanks that many nearby homeowners dealt with for decades. And with the proposed dam more than two feet higher, the groundwater problems would worsen for many neighboring homeowners during storm events.

9. Creating habitat for dangerous invasive species – Shallow, warm artificial ponds create ideal conditions for submerged aquatic plants, including non-native invasive species such as Hydrilla, a federally listed noxious weed. There’s a high likelihood that Hydrilla will occupy the impoundment if a new dam is built because the plant dominated the former Stump Pond – and the plant’s root system can persist for years and resprout in the right conditions.

10. Creating conditions cyanobacteria outbreaks – The conditions created by a new pond – high nutrient levels and warm temperatures – will provide ideal conditions for the outbreak of cyanobacteria and other harmful algal blooms, which can have significant impacts on wildlife and pose health risks to people and pets. Several outbreaks had already occurred in the former Stump Pond.