LOCATION.--Lat 42°55'51.9", long 76°10'22.7" referenced to North American Datum of 1983, Onondaga County, NY, Hydrologic Unit 04140201, at Onondaga Dam on Onondaga Creek, 0.5 mi downstream from West Branch Onondaga Creek, 3.5 mi southwest of Nedrow, 4.0 mi south of Syracuse, and 12.6 mi upstream from Onondaga Lake.
DRAINAGE AREA.--69 mi².  
PERIOD OF RECORD.--June 1949 to September 1952 (monthly elevations and contents), October 1952 to March 1998, September 2022 to current year. Prior to September 2022, published as "Onondaga Reservoir near Nedrow".
GAGE.--Water-stage recorder and crest-stage gage.  Reservoir elevation record is provided in Mean Sea Level, not NGVD29 as published (levels by Corps of Engineers). Reservoir elevation record is also provided in NAVD of 1988. To convert Mean Sea Level to NGVD of 1929, add 0.67 ft. To convert Mean Sea Level to NAVD of 1988, add 0.14 ft.
COOPERATION.--Capacity table provided by Corps of Engineers.
REMARKS.--

Reservoir is formed by a rolled earthfill dam, completed by Corps of Engineers in August 1949 for flood control; first used for flood regulation about a year prior to completion. Usable capacity, 18,200 acre-ft between elevations 457.0 ft, conduit invert at intake, and 504.5 ft, crests of spillway. No dead storage. The flood-control works consist of a pressure conduit and a side-channel spillway and are not provided with gates. Water is stored during high flows and released gradually. Storage includes minor diversion from Gate House Pond in headwaters of West Branch Tioughnioga River basin.

Capacity table (elevation, in feet, and contents, in acre-feet)

Elevation  Contents      Elevation     Contents   

460.0          0           470.0         700
461.0          5           473.0       1,420
462.0         15           478.0       2,880
464.0         50           482.0       4,230
467.0        225           486.0       6,010

EXTREMES FOR PERIOD OF RECORD.--Maximum elevation, 485.9 ft above Mean Sea Level datum (486.04 ft above NAVD of 1988), Apr. 1, 1960, contents, 5,960 acre-ft; no contents many days.

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Peak Flow and Stage Information

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