During winter months, cold and ice may result in inaccurate real-time lake or reservoir elevation data. Adjustments or deletions of this data can only be done after detailed analysis.

 

SURFACE-WATER RECORDS
LOCATION.--Lat 40°38'37", long 74°55'25" referenced to North American Datum of 1983, Union Township, Hunterdon County, NJ, Hydrologic Unit 02030105, at dam on Spruce Run, 0.5 mi north of Clinton, and 0.6 mi upstream from mouth.
DRAINAGE AREA.--41.3 mi².
PERIOD OF RECORD.--November 1963 to current year. Prior to October 2009, month-end contents and elevation provided by New Jersey Water Supply Authority.
REVISED RECORDS.--WDR NJ-84-1: (M). WDR NJ-85-1: 1984.
GAGE.--Water-stage recorder with telemetry. Datum of gage is National Geodetic Vertical Datum of 1929.
COOPERATION.--Records provided by New Jersey Water Supply Authority.
REMARKS.--Reservoir is formed by earthfill dam with concrete spillway; dam completed in October 1963 with crest of spillway at elevation 273.00 ft. Usable capacity, 11,000,000,000 gal. Dead storage 300,000 gal. Reservoir used for water supply and recreation. Outflow mostly regulated by gates. Water is released to maintain minimum flow on the South Branch Raritan River and for municipal supply. Records given herein represent usable capacity. Annual extremes beginning in water year 2014 can be obtained by using this link. Prior to water year 2014, annual extremes can be obtained on the respective annual water year summary.
EXTREMES FOR PERIOD OF RECORD.--Maximum contents, 11,862,000,000 gal, Sep 8, 2011, elevation, 274.84 ft; minimum contents, 3,100,000,000 gal, Oct 18, 1983, elevation, 246.68 ft.

WATER-QUALITY RECORDS
PERIOD OF RECORD.--Water years 1964, 2010-11.
REMARKS.--Cooperative Network Site Descriptor: Development of Mercury-Bioaccumulation Factors special study site.
COOPERATION.--Physical measurements and samples for laboratory analyses were provided by personnel of the NJ Department of Environmental Protection.

NOTICE: Due to gate operations managed by NJWSA, large and sudden drops and rises in reservoir elevation can be noticed online due to draw-down at our water-level sensor. Online data may be erroneous, but will be made available until it can be reviewed. Data affected by draw-down will be removed.

The water temperature data for this station are temporary and will only be displayed for 120 days. Although the instrumentation is calibrated at least once/year, the temporary classification means that documented routine inspections and other quality assurance measures are not performed that would make the data acceptable for archival, retrieval, or future use in general scientific or interpretive studies.