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Description of Onondaga Lake
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Onondaga Lake
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maximum depth
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19.5 m
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mean depth
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10.9 m
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surface area
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12 km2
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volume
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131x106 m3
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watershed area
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642 km2
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length
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7.6 km
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width
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2.0 km
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average elevation
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111 m
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average flushing rate
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4 times/year
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monitoring site
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43º 04’ 43” N
76º 11’ 50” W
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Onondaga Lake has a surface area of 12 km2 (4.5 square miles), a volume of 131 x 106 m3 (35 billion gallons), and a maximum depth of 19.5 m (64 feet). The watershed (642 km2, 244 square miles) supports a population of approximately 450,000, that resides mostly in Syracuse and adjoining suburbs. The lower reaches of Onondaga Creek drain a significant portion of the City of Syracuse, and receive inputs of dilute untreated domestic waste during runoff events (storms and snow melts) via approximately 40 combined sewer overflow structures (CSOs) within the City. Effluent discharged to the southern end of the lake from the Metropolitan Syracuse Wastewater Treatment Plant (METRO) contributes almost 20% of the annual inflow, and often is the single largest input in late summer. No other lake in the United States receives as much of its inflow as treated wastewater. The lake flushes approximately 4 times a year, that is its water volume is replace four time each year. This is much more rapid than Skaneateles Lake which flush once every 12 years or Lake Superior flushes only once every 191 years! With its rapid flushing rate, Onondaga Lake should respond quickly to changes in material loading.
Onondaga Lake and adjoining portions of the Seneca River are tightly linked with respect to water quality, ecological concerns and management issues. Fish populations a ctively migrate between these systems (i.e., fish that have been trapped and tagged in Onondaga Lake have been caught by fishermen in the Seneca Rivers and Oneida Lake).
Municipal Waste
Aquatic plants (i.e. algae) require phosphorus and nitrogen for growth. Excessive amounts of these nutrients can cause a lake to become overgrown with aquatic plants. High concentrations of nitrogen species (i.e., free ammonia) are harmful to other aquatic life (i.e., fish).
The Metropolitan Syracuse Wastewater Treatment Plant (METRO) has discharged its effluent directly to the southern end of the lake since the 1920's. The input of domestic waste had profound negative impacts on the lake, particularly associated with the large loads of ammonia (nitrogen) and phosphorus. These loads caused routine violations of toxicity standards for forms of nitrogen , and severe manifestations of cultural eutropication, including algae blooms , poor clarity, and depleted oxygen . Dramatic reductions in loading of these constituents from METRO have been achieved through implementation of advanced treatement. These reductions have eliminated violations of toxicity standards for forms of nitrogen and have transformed the lake from hypereutrophic to upper mesotrophy. However METRO remains (by 2012) the single largest source of bioavailable phosphorus and nitrogen (in the form of nitrate, that is not toxic) to the lake.
Industrial Waste
The primary source of industrial waste to the lake has been a soda ash (Solvay Process)/chlor-alkali facility located on the lake's western shore. This facility discharged large quantities of ionic (mostly chloride, sodium, and calcium waste to the lake, until its closure in 1986. It was the single largest source of chloride to Lake Ontario The residual load of ionic waste from approximately 1,000 acres of "waste beds" adjoining the lake continues to be substantial (approximately 12% of pre-closure load). Large sediment loads that enter the lake from Onondaga Creek have been attributed to solution mining activities by the manufacturer. This facility also discharged approximately 75,000 kg of mercury to the lake over the 1946-1970 interval.
Onondaga Lake as a Community Resource
Although Onondaga Lake is severely impacted by pollution, it remains a potentially valuable resource to the community. The lake's setting draws many visitors. More than one million people visit Onondaga Lake each year, making it one the most visited lakes in Central New York. However, the recreational activities are largely limited to the surrounding park land owned by Onondaga County. Imagine the potential of this resource if the waters of the lake could be fully utilized.
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