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Hudson River Tidal Wetlands Inventory

Tappan Zee Bridge to Troy Dam: Inventory and Mapping

The Hudson River is host to a wide variety of plants and animals, each requiring specific conditions to live, grow and reproduce. The Hudson River estuary supports this rich living resource through its varied wetland habitats and tributary streams. The New York State Department of Environmental Conservation (DEC) is mapping the Hudson River tidal wetlands from the Tappan Zee Bridge north to the Troy Dam. DEC is undertaking this inventory as one of the 20 commitments of the Hudson River Estuary Management Plan released by Governor Pataki in May 1996.

Hudson River Tidal Wetlands

Mapping the Hudson River Tidal Wetlands will allow New York State to focus on three areas of wetlands management concern:

1. Achieving a no net-loss of wetlands and littoral zone resources
2. Improving wetlands regulation
3. Managing and improving wetland resources through restoration and enhancement activities.

DEC staff and contractors walked and flew along the river to identify tidal wetlands categories and upland boundaries by observing vegetation and inundation. In addition to the field work, contractors interpreted summer infrared aerial photography and developed a geographic database. This database has been compiled into a stand-alone 2 CD set ("Upper Hudson River Estuary Wetland Mapper") which includes tidal wetland zones, mosaicked arieal infrared summer photographs, and oblique photographs. For a copy of this CD set, please contact Hudson River Estuary Program.

Please check out the available aerial photography and maps.

For information on Piermont Marsh, Iona Island, Tivoli Bays, and Stockport Flats, visit the Hudson River National Estuarine Research Reserve web page.

Lower Hudson River and NYC Five Boroughs: Trends Analysis

In 1987 the New York State Legislature passed Section 11-0306 of the Environmental Conservation Law. Known as the Hudson River Estuary Management Act, this law directs the Department of Environmental Conservation (DEC) to develop a management program for the newly-created Hudson River Estuarine District and associated shorelands. The Estuarine District includes the estuary from the Troy Dam south to the Verrazano Narrows and the tidal portions of the rivers tributaries. The purpose of the Program is to provide an holistic approach to the management activities both within DEC as well as with other government agencies responsible for the estuary's resources.

One component of the Action Plan is to map the tidal wetlands along the Hudson River's shore and it's tributaries. The northern portion (Tappan Zee Bridge to Troy Dam) has never been mapped, efforts are now underway to map this portion of the River. The southern portion of the River (Tappan Zee Bridge to New York City and it's 5 Boroughs) was mapped in 1974 along with the rest of the State's tidal wetlands under Article 25. Aerial infrared photographs were taken. The tidal wetland boundary was identified and placed on 1 inch = 200 feet black and white Mylar maps, produced from the aerial infrared photos. These maps after field inspections and public hearings became the Official Tidal Wetlands Maps of New York State. Under a contract with Dames and Moore aerial infrared photographs the original photography. The tidal wetlands boundary (TWB) will be identified. The new wetland boundary, the aerial infrared photographs and the 1974 TWB will be computerized and placed on a GIS (Geographic Information System) using ArcView and Imagine software. A trends analysis will be conducted comparing the differences between the 1974 and the present TWB. Areas that show a change will go through a map change process to be added to the Official Tidal Wetlands Inventory. Areas that show a loss will be suggested for further studies to determine the cause and come up with a solution to manage the site.

Mapping the Hudson River's Tidal Wetlands will allow New York State to focus on three areas of wetlands management concern: achieving a no net-loss, improving the state's regulatory authority over the district's tidal wetlands and managing the districts wetland resources through restoration and enhancement activities.