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Lower Hudson Watershed

Published Water Quality Monitoring and Assessment Reports

Biological Assessment Reports

Groundwater Study Reports and Data

The links below go to United States Geological Survey (USGS) web pages. The DEC partners with the USGS to conduct research and publish the following reports and data for groundwater resources of the state. An overview of the monitoring project for the entire state, including links to methods, maps, and publications, can be found on USGS's 305(b) Ambient Groundwater Quality Monitoring webpage.

Watershed Management Plans

Facts about this Watershed

Map of NYS identifying the Lower Hudson River Watershed
Click to view detailed map of the watershed

The Lower Hudson Watershed makes up about 40% of the larger Hudson/Mohawk River Basin which is one of the largest drainage areas on the eastern seaboard of the United States. Most of this 12,800 square mile basin lies in New York State, with small portions in New Jersey, Connecticut, Massachusetts and Vermont. The Lower Hudson Watershed extends from the Battery at the southern end of Manhattan to the Troy Dam at the confluence of the Mohawk River. Along this entire 153 mile reach the Hudson is actually a tidal estuary, rather than a river.

Location: Southeastern New York State.

  • Most of Westchester, Putnam, Orange, Ulster, Columbia and Albany Counties,
  • Much of western and central Dutchess, eastern Greene, and southern Rensselaer Counties, and
  • Smaller parts of New York (Manhattan), Bronx, Rockland, Sullivan, Schoharie and Schenectady Counties.

Size: 4,982 square miles of land area within New York State (excluding the Upper Hudson and Mohawk River Watersheds, which are addressed separately).

Rivers and Streams: 8,861 miles of freshwater rivers and streams. Major tributary watersheds to the Hudson River Estuary (excluding the Upper Hudson and Mohawk Watersheds):

  • Rondout/Wallkill Rivers (1,584 river/stream miles)
  • Stockport/Kinderhook Creeks (1,077 miles)
  • Catskill Creek (927 miles)
  • Esopus Creek (631 miles)
  • Croton River (607 miles)

Lakes, Ponds and Reservoirs: 324 significant freshwater lakes, ponds, and reservoirs (37,676 acres):

  • Ashokan Reservoir (8,060 lake/reservoir acres)
  • Rondout Reservoir (2,024 acres)
  • New Croton Reservoir (1,949 acres)
  • Alcove Reservoir (1,363 acres)
  • Cross River Reservoir (899 acres)
  • Muscoot/Upper New Croton Reservoir (770 acres)

Estuary Waters: 78,322 acres of estuary along the entire 153 mile length of the Lower Hudson.

What You Can Do

Each of us lives in a watershed. On our Watershed Stewardship page are some tips on actions that you and your friends can take to help your watershed.

More about Lower Hudson Watershed: