During winter months, cold and ice may
result in inaccurate real-time gage height and streamflow data.
Adjustments or deletions of this data can only be done after detailed
Funding for this site is provided by:
Lat 40°39'58", long 74°24'14"
referenced to North American Datum of 1983, Watchung Borough, Somerset
County, NJ, Hydrologic Unit 02030105, on right bank at Seeley Mills,
150 ft downstream from Blue Brook, 200 ft downstream from bridge on New
Providence (Diamond Hill) Road, and 0.5 mi northwest of Scotch
PERIOD OF RECORD.--
Annual maximum gage, water years 1927-38,
1958-68 (in files of Union County Park Commission), and 1969-79.
Fragmentary records 1944-53 (in the files of the U.S. Geological
Survey). Occasional low-flow measurements, water years 1959-64, 1969.
Continuous-record discharge station, June 1979 to current year.
WDR NJ-81-1:1979(M). WDR NJ-87-1:1971(M),
Water-stage recorder with telemetry and crest-stage gage.
Datum of gage is 184.44 ft above NGVD of 1929. From 1944 to 1953,
water-stage recorder and masonry dam about 500 ft downstream, above
lower Seeley Mills dam at different datum. From July 1969 to May 1979,
crest-stage gage about 550 ft downstream below lower Seeley Mills dam
(washed out May 29, 1968) at different datum. From May 1979 to March
2019, water-stage recorder about 100 ft downstream at same datum.
Records fair, except for estimated discharges and
discharges below 1 ft³/s, which are poor.
EXTREMES FOR PERIOD OF RECORD.--
Maximum discharge, 6,240 ft³/s,
Aug 2, 1973, gage height 16.10 ft, site and datum then in use; minimum
discharge, 0.00 ft³/s, Sep 11, 1981.
EXTREMES OUTSIDE PERIOD OF RECORD.--
Flood of July 23, 1938
reached an elevation of 196.5 ft (New Jersey Geological Survey datum;
above lower Seeley Mills dam), discharge, 5,840 ft³/s (computed by
State Water Policy Commission).
National Weather Service flood stage for
this gage is 5.5 ft.