The Hudson River near Castleton, showing the historic
shoreline (red lines), historic islands (orange) and dikes
(blue lines). Areas of land inside the historic shoreline that
are not historic islands are areas that were filled when the
navigation channel was dredged.
The Hudson River Estuary has been transformed by human actions, significantly altering and reducing habitats critical to supporting a productive, diverse and resilient ecosystem. Hudson River habitats have been lost due to several large and small scale development projects including construction of the federal navigation channel and the railroads, as well as thousands of smaller developments that took place over hundreds of years.
Early attempts to 'improve' the Hudson's navigation channel included construction of dikes along the length of the upper third of the estuary in an attempt to constrict the main channel and increase flow. Later projects included dredging the main channel, then depositing the dredged material in the shallows behind the dikes to eliminate side channels, connect islands, and further constrict the flow of water to inside the main channel. These actions resulted in loss of nearly 4,000 acres of shallow water habitat including the near complete elimination of side channels in the upper third of the estuary.
Restoration will help restore fisheries
Within the past 70 years, the populations of many estuarine and coastal migratory fish that spawn in the Hudson, including American shad (Alosa sapidissima), have declined dramatically. Fisheries management experts have identified several potential causes for the decline of migratory fish such as river herring and shad, and have sought to protect spawning fish by taking management actions to reduce commercial and sport fishing mortality. However, the recovery of these fish stocks is at least partially dependent on the Hudson's ability to produce future generations. Successful restoration of high-quality spawning, nursery and refuge habitats in the Hudson River estuary will allow greater spawning success and survival of young-of-year fish for a number of species. Without restoration, recovery of these economically important species may be limited.
Restoration will enhance ecosystem resiliency
Habitat restoration supports increased resiliency which is critical to maintaining a functioning ecosystem during time of environmental stress such as periods of extreme weather, climate change and accelerated sea-level rise. A healthy ecosystem with greater biodiversity and diversity of habitats can be more adaptive as it responds to climate change. Habitat protection and restoration will preserve the many critical functions these habitats contribute to the ecosystem, including fish spawning, nursery and forage habitats, and improved water quality. Preserving low-lying natural areas along shorelines to allow wetlands to 'migrate' and removing dams to restore sediment transport in tributaries will allow shallows and wetlands to continue to exist as sea-level rises. Construction of side channels in the upper estuary will increase spawning and forage habitats for many species. Side channels also provide critical low-flow refuge habitats for fish and wildlife during high flow periods associated with high discharge, extreme weather events. Implementing ecologically enhanced shoreline practices will allow communities to protect important properties and infrastructure from rising sea-levels and extreme storms while preserving habitat value.
The Hudson River Habitat Restoration Plan
The Hudson River Estuary Habitat Restoration Plan (PDF, 2.1 MB) was developed with input from State and Federal regulatory agencies, scientists, natural resource managers and non-governmental organizations. Many technical resources were used to develop an understanding of present day conditions and how they have changed over time due to human action.
Based on this research, four priority habitats for restoration were identified: intertidal habitats, shallow water, shorelines, and tributary habitats. Although these habitat types do not represent all those that have been lost or degraded, they do represent significant and feasible opportunities to improve habitats and the health and resiliency of the Hudson River Estuary ecosystem. To restore these habitats, five restoration actions were identified:
- Preservation of existing estuary habitat, including protection of buffer lands that will be inundated in the future as sea level continues to rise;
- Implement side channel restoration, including tidal wetlands, vegetated shallow waters, back waters and intertidal habitats;
- Promote and implement fish passage, dam removal & culvert right-sizing in tributaries to the Hudson;
- Promote and implement use of ecologically enhanced shoreline structures where shoreline stabilization is required to protect property, infrastructure or other economic assets;
- Implement programs to control and prevent introduction of invasive plant and animal species.