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Allegheny River Watershed

Published Water Quality Monitoring and Assessment Reports

Biological Assessment Reports

Links lead to NYS Library:

Watershed Management Plan

Chautauqua Lake Watershed Management Plan (leaves DEC website)

Facts about this Watershed

Map of NYS identifying the Allegheny Watershed
Click image to view detailed map of watershed

The Allegheny River originates in north central Pennsylvania and flows west across southwestern New York State. The Allegheny River Watershed is part of the headwaters of the larger Ohio River Basin (204,000 square miles). Some of the larger tributaries of this watershed join the Allegheny River outside New York State and eventually empty into the Gulf of Mexico.

Location: Southwestern New York State

  • Most of Cattaraugus and Chautauqua Counties, and
  • Portion of southwest Allegany County.

Size: 1,920 square miles of land area within New York State.

Rivers and Streams: 4,086 miles of freshwater rivers and streams. Major tributary watersheds to the Allegheny River in New York State:

  • Conewango Creek (1,406 river/stream miles)
  • Cassadaga Creek (586 miles, within Conewango Watershed)
  • Olean Creek (487 miles)
  • Great Valley Creek (357 miles)
  • French Creek (186 miles)

Lakes, Ponds and Reservoirs: 23 significant freshwater lakes, ponds, and reservoirs (26,335 acres):

  • Allegheny Reservoir (10,987 acres)
  • Chautauqua Lake (13,427 acres)

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 Allegheny River Watershed: