Nissequogue River
Let the Nissequogue Run!
The dam on Stump Pond in Blydenburgh County Park failed during a storm in Mid- August 2024. On average, the storm produced over 10 inches of rain in a very short amount of time; resulting in flash flooding events that caused damage to roads, homes, and businesses across Long Island. Within a matter of hours of the dam failure, Stump Pond completely drained and all that remains are the stumps that gave “Stump Pond” it’s iconic name.
As time goes by–if left untouched– the natural streambed, that used to flow freely hundreds of years ago, will rechannelize itself; and the native seedbank that has laid dormant in the pond’s basin will begin to grow. The mucky site we currently see, will quickly become vegetated and grow into a lush meadow-like marshland. This site can eventually turn back into a riparian forest ecosystem that hasn’t existed in nearly 230 years! Due to the shear size of Stump Pond, it has significant ecological potential as a place where native bird populations, migratory fish, and other native riverine species can once again find a home.
As of November 2024, Suffolk County is looking to repair the dam and recreate Stump Pond and has announced a Request for Proposals for designs for a new dam. However, we are urging the county and other local decision makers and stakeholders to please consider all the factors and weigh the economic and ecological costs before making such a significant decision.
A Vision of the Future of Stump Pond
Not repairing the dam can create a multitude of new outdoor recreation opportunities while also improving habitat for local and migratory terrestrial, avian, and aquatic species.
The Nissequogue River is one of the four significant river systems on Long Island, and the largest on the north shore of Long Island. The headwaters of the Nissequogue River were dammed in 1798 for the purposes of creating a grist mill. Stump Pond gets it’s name from the stumps that are now visible in the pond basin, along the former river boundaries. Though they have not been cored and tested yet, it is suspected that these stumps could be Atlantic White Cedar, now a rare native evergreen tree found on the east coast. A small stand of Atlantic White Cedar still exists in the southwest corner of Stump Pond and could repopulate the pond basin again, if given the chance!
Seatuck has been working with local partnering agencies to form a coalition to not repair the dam and let this portion of the Nissequogue River return to it’s natural, free-flowing state. In order to showcase this vision of what Stump Pond could look like in a few years, Save The Sound has created several visual renderings based on their expertise with dam failure and dam removal projects!
Ecological and fiscal benefits of a free-flowing Nissequogue
Allowing the stream to return to a natural state will provide a range of ecological and fiscal benefits:
Return of Alewife and American Eel Removal of the dam creates access for migratory fish that provide forage for everything from Bluefish to Harbor Seals, and are critical to the health of the coastal ecosystem.
Habitat for Sea-Run Brook Trout Free-flowing cold water and access to the bay are necessary for the return of Brook Trout, an iconic South Shore species and New York’s State Fish (and only native trout).
Conditions for River Otters The protected natural corridor and unfettered access are ideal conditions for the potential return of these important apex predators, which are continuing their return to Long Island.
Greater Diversity of Birds Although artificial impoundments attracts both native and non-native waterfowl and overwintering migratory species, reestablishing freshwater wetlands, mudflats, and riparian habitats attracts more bird species and creates even better bird watching opportunities.
Native Wetland Plant Species With the pond gone, the site will turn back into a riparian wetland, creating habitat for marshland-specific plants like grasses and small annual and perennial plants, and eventually, larger, woodier plants, like shrubs and trees, will begin to grow.
Resiliency for Flooding and Sea Level Rise Removing the dam will allow flood waters from rising seas or storm events to fill the empty basin that once was the pond, instead of covering adjacent roads or other critical infrastructure.
Dam Repair Savings Allowing the stream to run will avoid short and long term repairs to the aging dam infrastructure, which could easily run into the millions of dollars.
Invasive Species Savings Allowing a free flowing stream will avoid costly measures to address continuous issues with sedimentation and invasive aquatic species in the pond.
Case Studies of Past Dam Failures on Long Island
There have been four previous dam failures on Long Island over the past two decades. None were repaired and all have resulted ecological restoration success stories. There has yet to be an intentional dam removal on Long Island.
Harrison Pond, Kings Park A rainstorm in 2004 caused the dam on a small tributary of the Nissequogue River to fail, resulting in a riparian meadow that remains part of a local park and a community resource.
Hempstead Lake State Park A dam at one of the “northern ponds” failed at Hempstead Lake State Park during Hurricane Irene in 2011, which created an area of mudflats and shallow emergent wetlands. This site is now one of the most important bird habitats in Nassau County, especially during migration season.
Sunken Meadow State Park In 2012, Hurricane Sandy destroyed the lower dam at Sunken Meadow State Park. It has become one of the most celebrated ecological restoration projects on Long Island. Allowing the natural stream to flow and the tidal hydrology to be restored has resulted in the reestablishment of salt marsh habitat and is a location that attracts a diverse abundance of local wildlife (and wildlife lovers!).
West Brook, Great River The only dam at West Brook, a tributary of the Connetquot River, failed during a rainstorm in 2019. Seatuck has been closely monitoring and shepherding carefully, has been transforming into an amazing riparian meadow that is dominated by native plant species. The site is rich in abundance and diversity of birds and pollinators as well, it has become one of the most ecologically significant sites in western Suffolk County.
Concerns about the Lost Pond
The following are some concerns that have been raised about the loss of the artificial pond:
More Flooding? Quite the opposite, actually. Healthy riparian systems provide “natural infrastructure” and can be very resilient against flooding events by capturing, retaining, and filtering stormwater much more efficiently than an artificial pond can.
Lost Fishing? Not repairing the dam would result in the loss of habitat for non-native warm water fish species, such as largemouth bass, that provide recreational fishing opportunities. Allowing the stream to flow naturally, however, will create offsetting recreational fishing opportunities for native Brook Trout and other cold-water species. Further, while fully connected, flowing streams are rare on Long Island, there are a great number of warm-water ponds and lakes for recreational fishing, including nearby Lake Ronkonkoma in Ronkonkoma.
Lost Birds? Many of the waterfowl species that used the pond, such as ducks and geese will continue to use the stream and surrounding habitat available for them at Millers Pond, Lake Ronkonkoma, and Artist Pond and many other local lakes and ponds. Further, the diversification of the riparian area, to include mudflats, meadows, and other habitat types will benefit and provide nesting and foraging opportunities for a greater number of native and migratory bird species.
Other Lost wildlife? No, most species that used the pond, including native turtles and amphibians, will continue to find suitable habitat in the stream and adjacent wetlands.
Costly Replanting? No, native plant communities (e.g. emergent freshwater wetlands) would establish their own and transition to coastal forest over time. Like anywhere, invasive species could impact the quality of the habitat.
Lost Aesthetic Views and Accessibility? Not lost, just changed. While the pond would be gone, the natural stream would continue to flow through the site, reestablishing the stream channel. Eventually, the rest of the pond basin would fill in with plants, typically found in wetland habitats. For the next several years, visitors would be able to overlook a riparian meadow. As the years go by, this site will gradually mature back into a forest with a natural running river. This can create many new opportunities for outdoor recreation including: expanding walking/horseback trails throughout the pond basin, provide cold-water fishing in the river, an increase in bird diversity for bird watchers, and more.
Related Information
Dam Failures
Rebuilding failed dams may occasionally make sense, but in most cases allowing rivers and streams to revert to their natural state will help make the region and its coastal ecosystem more healthy, resilient and sustainable.
West Brook
The only dam on West Brook, a major tributary of the Connetquot River, failed in 2019 and allowed the artificial pond behind it to drain. For the first time in over 100 years, the brook could once again flow naturally from its headwaters in Bayard Cutting Arboretum State Park down to the tidal reaches of the Great South Bay. It is now one of a only a few free-flowing streams on Long Island. It has great ecological potential as a place where migratory fish can return and other native riverine species can once again find a home.
Other Streams
In addition to our work at Penataquit Creek, Bellmore Creek and West Brook, Seatuck has been involved in connectivity and restoration efforts across Long Island over the past decade as part of the River Revival Project. The following are some examples highlight the extent of this work.