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Facts about Owasco Lake*
• Length — 11.1 miles
• Average width — 1.3 miles
• Sixth Largest Finger Lake
• Average depth — 96 feet
• Maximum depth — 177 feet
• Hydraulic retention — 3 to 4 years
(Hydraulic retention is the amount of time the water will remain in the lake before being replaced. Owasco Lake has a short retention time compared to many of the other Finger Lakes. For example, Cayuga Lake has a retention time of 10 years and Seneca and Skaneateles Lakes have retention times of 18 years. Hydraulic retention time is influenced by the size of the watershed and the amount of water coming from streams, runoff, and groundwater sources.)
• Gallon capacity — 260 billion gallons
• Length of shoreline — 25 miles
• Owasco Lake supplies drinking water to over 40,000 people in Cayuga County, which is more than 50 percent of the county’s population. Drinking water is pumped from Owasco Lake through two intakes: one for the city of Auburn and one for the town of Owasco.
• The town of Owasco provides water to its municipal water users and some residents in the town of Fleming.
• The city’s intake withdraws and treats water for the city of Auburn, and then sells water to the towns of Aurelius, Sennett, Throop, Montezuma, Mentz, and Brutus, and the villages of Weedsport and Port Byron, and sections of the towns of Springport and Fleming. The total water produced in 2019 was 1,370,368,000 (one billion, three hundred seventy million, three hundred sixty-eight thousand) gallons. The daily average of water treated and pumped into the distribution system was 3,756,814 (three million, seven hundred fifty-six thousand, eight hundred fourteen) gallons per day.
• In 2019, the city purveyed 480,000 units (100cuft or 748 gallons) outside of the city for a total of $1.35 million dollars of revenue to the City (5% additional rate to the city’s internal rate of $262/unit).
• Aurelius, Sennett, and the Cayuga County Sewer and Water Authority purvey to other customers.
• According to the Cayuga County Office of Real Property Services (in 2019), there are 1028 parcels with Owasco Lake frontage with a total assessed value of $295,630,478.
• The first HABs detection in the lake was in 2014 and in the finished drinking water in 2016.
Facts about the Watershed
• Watershed size — 208 square miles (The Owasco Lake Watershed encompasses three counties — Cayuga (81.5%), Tompkins (16.2%) and Onondaga (2.3%) — which includes 15 towns and two villages.)
• About 16,000 residents reside within the watershed
• Miles of maintained roads — 480 miles
• Three major land uses — Cropland/pasture (54.9 percent), forest (40.6 percent), residential (2.1 percent)
• Cayuga County has the second most dairy cows (~35,000) in NYS with more than ten having in excess of ~1,000 cows each (CAFOs). There are four CAFOs with land in the Owasco Lake Watershed- Sunnyside Farms, Spruce Haven, Twin Birch, Allen.
• Based on a 2024 Cayuga County Soil and Water Conservation District (CCSWCD) inventory, 167 farms exist within Cayuga County’s portion of the Owasco Lake watershed. Of those farms, 138 farms (83%) are enrolled in CCSWCD’s Agricultural Environmental Management (AEM) program..
• The Owasco Inlet supplies the lake with ~50-60 percent of its water. Dutch Hollow Brook contributes ~15-20 percent, Veness Brook and Sucker Brook combine for ~15 percent and more than 50 small and intermittent streams contribute the remaining 10 percent.
• Owasco Lake has the largest watershed to lake ratio (~20:1) of all the Finger Lakes. This ratio means that there are approximately 20 square miles of land in the watershed for every one square mile of lake. Therefore, Owasco Lake’s water quality is greatly impacted by the activities occurring on the land. Some of the nearby Finger Lakes have the following ratios: Cayuga Lake — 12:1, Skaneateles Lake — 4:1, Seneca Lake — 7:1.
• Owasco Lake is one of 11 Finger Lakes. The entire Finger Lakes drainage area is 2,629 square miles, resulting in 8.2 trillion gallons of water.
• There are more than 1.5 million residents in the surrounding regions and more than 200 million gallons of water is withdrawn from the Finger Lakes for drinking water every day.
• The US Environmental Protection Agency’s guidance for total phosphorus concentration in streams is 33 micrograms/liter, while a streams guidance value of 20 micrograms/liter has been recommended within NYS clean water plans.
• NYSDEC regulations, 6 CRR-NY Part 703, has water quality standards pertaining to turbidity in streams- no increase that will cause a substantial visible contrast to natural conditions.
• A healthy 100-foot-tall tree has about 200,000 leaves. A tree this size can take 11,000 gallons of water from the soil and release it into the air again, as oxygen and water vapor, in a single growing season.
*Unless otherwise stated, Lake and Watershed Facts are Based on 2019 Rates and Census Data.
Map of Protected Streams (blue)
