Conesus Lake NAM-11

Riparian Nation(s) USA
Surface Area 13 km2 Mean Depth 11.5 m Volume 0.15 km3
Shoreline 29.6 km Catchment Area 167.6 km2 Residence Time 3.2 yr
Frozen Period Dec-Mar Mixing Type Dimictic Morphogenesis/Dam
Related Info/Site


Conesus Lake is the westernmost of a group of long and narrow lakes located in western New York State known as the Finger Lakes. The basins of these north- south oriented lakes were formed by the advance of ice masses during the Ice Ages, and further sculpted by glacial meltwater during the interglacial and postglacial periods.

The climate of Conesus Lake is characterized by cold, snowy winters and warm, dry summers; and the lake regularly freezes over in the winter. Although the Finger Lakes region is now well-known for its many vineyards and orchards, it had been densely forested up until the early 1800's when large areas were cleared for agriculture by white settlers. The forests are now in the process of expanding as marginal farmland is abandoned and gradually invaded by trees. Of the land contained within the drainage basin of Conesus Lake, approximately half is considered active agriculture, 30% is forested, and 3% is residential.

Historically, the lakeshore has served mainly as a location of summer cottages. But over the past few decades, the situation has shifted from a summer recreation orientation to year-round residential use. Today, the entire shoreline is residential, occupied largely by commuters to nearby cities. In 1969, an advanced treatment plant was built on the Conesus Outlet to serve local needs. This was followed by the construction of an interceptor sewer surrounding the lake. By 1972, all individual disposal systems around the lake had been connected to the new perimeter sewer.

The water of Conesus Lake serves as a municipal water supply for several villages and towns. And, although there is little public access to the lake, local residents enjoy swimming and boating, as well as both summer and winter fishing. Native species of perch, walleye, northern pike, and bass constitute the bulk of the fish community. Although the lake is a relatively productive lake, grazing primarily by a single crustacean, Daphnia, helps keep the open water quite clear most of the time (1).

Photo of Conesus Lake
Photo: C. Rossano