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Seneca Lake Water Level Extremes
Record High
448.95 ft
April 26, 1993
Record Low
442.64 ft
March 14, 1978
Water Flow and Level Management
Seneca Lake is part of the network of lakes, canals and waterways that comprise the Oswego River Basin. The Oswego River Basin drains water from an area of 5,122 square miles, towards Lake Ontario.
Water can flow into Seneca Lake faster than it can flow out. The downstream area is relatively flat and the outflow is regulated; therefore the lake takes longer to drain than to fill. All of the water in Seneca Lake leaves near Geneva through the Cayuga-Seneca Canal. The brown arrows on the map below show the direction of watershed flow. The purple arrows show the direction of the canal flow.
Seneca Lake’s outflow is managed by Relevate Power (formerly Gravity Renewables), which operates hydroelectric power plants in Waterloo and Seneca Falls. Their goal is to generate clean energy while complying with federal regulations.
Water from Seneca Lake exits through the Cayuga-Seneca Canal, where flow is measured at a river gauge near the Rt-89 bridge in Seneca Falls. The New York State Canal Corporation also manages a small bypass gate and canal locks to ensure safe navigation downstream toward Lake Ontario.
Seneca Lake Rule Curve
Lake levels are guided by the Seneca Lake Rule Curve, developed in the 1970s, which defines acceptable high and low limits. These targets help balance water levels to prevent flooding or drought, while supporting recreation and protecting natural resources.
Summer Target
446.0 ft
± 0.3 ft (reached by mid-March)
Winter Target
445.0 ft
± 0.3 ft (reached by mid-December)
Each lake has a rules curve to guide its water level management. But there is only voluntary coordination among the lakes to manage both lake level and water discharge from each lake. Since each management unit has different objectives there are occasional conflicts.
How you can help protect the lake
High water events increase runoff, erosion, and nutrient pollution that can harm Seneca Lake’s water quality. SLPWA’s lake-saving programs help address these threats at the source.
Stormwater Nutrient Pollution Reduction (SNPR) Program
Our SNPR program works with landowners to reduce nutrient runoff, a leading cause of algae blooms and water quality degradation especially during high water events. Projects include shoreline buffers, rain gardens, and more.
Safety During High and Low Water
If You See High Water
- Stay away from flooded roads and shorelines
- Secure watercraft and dock equipment
- Do not drive through flooded areas
- Monitor the NWS Geneva gauge daily
High Water Warning Signs
- Water overtopping docks or seawalls
- Flooded shoreline access paths
- Unusually strong currents near the canal
- Official alerts from NYSDEC or NYSCC
Boating Safely
- Check lake level before launching
- High water = submerged hazards near shore
- Low water = exposed rocks and shallow areas
- Heed any posted advisories at boat launches
Protecting Your Property
- Know your property’s flood elevation
- Consider flood insurance if near the shoreline
- Avoid mowing or disturbing buffer vegetation
- Healthy buffers reduce erosion during high water
Current USGS Gauge Readings
Live streamflow — Seneca Lake watershed
Historical Lake Level Archives
2023
2019
2015
2022
2018
2014
2021
2017
2020
2016
