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
Funding for this site is provided by:
Lat 41°09'42", long 74°20'00"
referenced to North American Datum of 1983, West Milford Township,
Passaic County, NJ, Hydrologic Unit 02030103, in gatehouse near right
end of Greenwood Lake Dam on Wanaque River at Awosting.
PERIOD OF RECORD.--
June 1898 to November 1903, June 1907 to
current year (gage heights only prior to October 1953).
WDR NJ-94-1: 1993, WDR NJ-97-1: 1995-96.
Water-stage recorder with telemetry. Datum of gage is
608.86 ft above National Geodetic Vertical Datum of 1929 (levels from
New Jersey Geological Survey benchmark). Prior to Oct 1, 1931, records
provided by Morris Canal and Banking Company using staff gage on former
railroad bridge at site 100 ft upstream at datum 89.75 ft lower.
Reservoir is formed by earthfill dam with concrete
spillway; dam completed about 1837 and reconstruction completed in 1928
with crest of spillway 0.25 ft lower. Usable capacity, 6,860,000,000
gal between gage heights -4.00 ft, sill of gate, and 10.00 ft, crest of
spillway. Dead storage, 7,140,000,000 gal. Outflow mostly regulated by
two gates, 3.5 by 5.0 ft. Records given herein represent usable
capacity. Lake used for recreation. Diversions by North Jersey District
Water Supply Commission from Upper Greenwood Lake enter Greenwood Lake
via Green Brook. 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, 9,528,000,000
gal, Oct 9-14, 1903, gage height, 14.25 ft; minimum contents,
3,160,000,000 gal, several days in November 1900, gage height, 3.50