Department of Environmental Conservation

D E C banner

Oswego River/Finger Lakes Watershed

A brief overview of this watershed and its water quality is presented below. For more detailed information, published NYSDEC reports are also available.

Facts about this Watershed

Map of NYS identifying the Oswego River/ Finger Lakes Watershed
Click to view a detailed map of the watershed

The Oswego River/Finger Lakes Watershed is one of the largest in New York State and includes the drainages of the Oswego, Oneida, Seneca and Clyde Rivers. Its headwaters originate in the southwestern Adirondack Mountains in the east and along the northern edge of the Appalachian Plateau and flow across the central lowlands before emptying into Lake Ontario. The watershed includes most of the New York Finger Lakes; in fact, lakes make up about 6% of the total surface area of the watershed.

Location: Central New York State

  • All of Seneca County,
  • Most of Onondaga, Cayuga, Tompkins, Schuyler, Yates and Ontario Counties,
  • Much of Oswego, Oneida, Madison and Wayne Counties, and
  • Smaller parts of Lewis, Cortland, Chemung, Steuben and Livingston Counties.

Size: 5,070 square miles of land area entirely within New York State.

Rivers and Streams: 8,896 miles of freshwater rivers and streams. Major tributary watersheds to the Oswego River and Finger Lakes include:

  • Oneida River (2,330 river miles)
  • Clyde River (1,630 miles)
  • Cayuga Lake Tributaries (1,500 miles)
  • Seneca Lake Tributaries (1,240 miles)

Lakes, Ponds and Reservoirs: 76 significant freshwater lakes, ponds, and reservoirs (189,722 acres), including:

  • Oneida Lake (51,091 acres)
  • Cayuga Lake (42,812 acres)
  • Seneca Lake (42,646 acres)
  • Keuka Lake (11,712 acres)
  • Canandaigua Lake (10,605 acres)

How is the Water?

Water Quality in The Oswego River/Finger Lakes Watershed

In the Oswego River/Finger Lakes Watershed, about 43% of river/stream miles, and 97% of lake, pond and reservoir acres have been assessed (see Assessment Report).

Water quality Pie Chart. Rivers: 12% good, 26% Satisfactory, 5% Poor, 57% unassessed. Lakes: 2% good, 83% satisfactory, 12% poor, 3% unassessed
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 Oswego River/Finger Lakes Watershed is generally satisfactory to good. There are primarily two major water quality issues in the watershed. The first of these is the impact of past industrial activity such as municipal discharges, urban runoff and other sources on Onondaga Lake. Extensive remediation and water quality improvements over many years and continuing today are addressing these issues. The second concern is the protection of the water resources provided by the Finger Lakes from various point and nonpoint sources of pollution. Though these impacts are less severe, they constitute a more widespread threat to water quality in the watershed.

Major water quality concerns in the watershed are:

  • Legacy Industrial Discharges in Syracuse/Onondaga Lake area currently being remediated
  • Municipal Wastewater and Combined Sewer Overflows in Syracuse and other urban areas
  • Agricultural and Other Nonpoint Sources of nutrients and various other pollutants
  • Protection of Finger Lakes Resources, including drinking water and recreational uses

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

Fishing In The Finger Lakes

More about Oswego River/Finger Lakes Watershed: