Onondaga Lake is 4.6 miles long and 1 mile wide. Its average depth is 35 feet, and its maximum depth is 63 feet. It has a drainage basin of 285 square miles, covering all of the City of Syracuse and much of Onondaga County. The Onondaga Lake watershed is itself part of the Seneca River watershed.
The Lake is not used for drinking water by anyone. The Lake may not be used for contact recreation such as swimming. It is used for noncontact recreation such as fishing and boating. Fish consumption is restricted: no largemouth and smallmouth bass over 15 inches, no walleye, no more than one meal per month of other fish species, smaller largemouth, and smallmouth bass (2009).
The major natural tributaries to the lake are Nine Mile Creek and Onondaga Creek. Together they account for 70% of the total amount of water that flows into the lake each year. The Metropolitan Syracuse Wastewater Treatment Plant contributes 20% of the Lake's annual inflow, a significant proportion compared with other lakes nationwide. Other tributaries are Ley Creek, Bloody Brook, and Harbor Brook. Minor tributaries include Sawmill Creek, Tributary 5A, and the East Flume.
The tributaries flush the lake (replacing old water with new water) rapidly compared to most other lakes. The Lake is flushed approximately four times each year. By comparison, Skaneateles Lake is flushed only once every 12 years.
Water leaves the lake through a single outlet at the lake's north end. This outlet flows to the Seneca River and ultimately reaches Lake Ontario. (Click on image for larger view.)
Onondaga Lake has been important to human habitation of central New York since at least the Iroquois Confederacy in the 17th century. It was integral to the industrial development of the area through the 20th century. During that time, the lake became polluted from industrial and municipal sources.
Today, the pollution of the lake is being reduced or remediated with nearly $1 billion in investments of public and private funds. The communities around the lake are looking forward to increasing recreational uses of its waters.