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Lower Hudson Watershed

A brief overview of this watershed and its water quality is presented below. For more detailed information about the Lower Hudson Watershed, published NYSDEC reports are also available. General information about watersheds is available at the "We All Live in a Watershed" webpage.

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) include:

  • 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), including:

  • 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.

How is the Water?

Water Quality in The Lower Hudson Watershed

In the Lower Hudson Watershed, about 63% of river/stream miles, 72% of lake, pond and reservoir acres and 100% of estuary acres have been assessed (see Assessment Report).Water quality Pie Chart. Rivers:41% good, 18% Satisfactory, 4% Poor, 37% unassessed. Lakes:12% good, 5% satisfactory, 55% poor, 28% unassessed. Estuaries:Poor, 100%
Good water quality: Fully supports designated activities and uses
Satisfactory: Fully supports designated activities, but with minor impacts
Poor (Impaired): does not support designated activities and uses
Unassessed: Insufficient data available

Water quality in the Lower Hudson Watershed varies widely and in influenced by a wide range of pollutants and sources. Municipal wastewater, combined sewer overflows, urban/stormwater runoff and industrial impacts are associated with numerous population centers along the Hudson Valley, including one of the most densely populated areas in the world: New York City. Commercial and residential development increase impacts from runoff and wastewater discharges. In the considerable rural parts of the watershed, agricultural activities and other nonpoint sources generate less severe but also widespread impacts. Impairments related to the legacy PCB contamination of the Upper Hudson River are restrict fish consumption and commercial fishing.

Major water quality concerns in the watershed are:

  • Municipal Wastewater and Combined Sewer Overflow Impacts in New York City and other urban areas
  • Urban/Stormwater Runoff and Industrial Impacts in population centers
  • Agricultural and Other Nonpoint Sources of nutrients and various other pollutants
  • Impacts from Legacy Industrial PCB Discharges to Upper Hudson currently being remediated
  • Declining Fishery Stocks from habitat loss, power generation withdrawals and other causes
  • Protection of New York City Water Supply Reservoir (Catskill, Croton Reservoir Systems)

About Water Quality in New York State

Water chemistry sampling in a NYS stream
Water Chemistry Sampling

Each waterbody in NYS has been assigned a classification, which reflects the designated "best uses" of the waterbody. These best uses typically include the ability to support fish and aquatic wildlife, recreational uses (fishing, boating) and, for some waters, public bathing, drinking water use or shellfishing. Water quality is considered to be good if the waters support their best uses. NYSDEC routinely monitors and assesses water quality throughout the state and publishes detailed reports of these findings. For more information on these monitoring and assessment programs, see Water Quality Monitoring, Assessment and Planning.

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.

Biological kick sampling in a NYS stream
Biological Kick Sampling

Published Water Quality Monitoring and Assessment Reports

Watershed Management Plans

More about Lower Hudson Watershed: