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°34'14", long 74°40'45"
referenced to North American Datum of 1983, Branchburg Township,
Somerset County, NJ, Hydrologic Unit 02030105, on right bank, 400 ft
upstream from U.S. Route 202, 1.4 mi upstream from confluence with
South Branch Raritan River, and 2.7 mi west of Raritan.
PERIOD OF RECORD.--
June 1923 to current year. Monthly discharge
only for June 1923, published in WSP 1302. Prior to October 1943,
published as "at Milltown".
WSP 1552: 1924-26, 1928-35. WDR NJ-79-1:
1971-78(P). WDR US-2011: 1997(P), 2004-10(P).
Water-stage recorder with telemetry. Concrete control
since Sep 1, 1936. Datum of gage is 50.43 ft above NGVD of 1929. Prior
to Oct 17, 1936, non-recording gage at site 30 ft downstream at same
Records good, except for estimated discharges, which
are fair. Stage-discharge relationship affected by variable-stage
backwater from the confluence with the South Branch Raritan River. From
Dec 10, 2010 to present, water-stage recorder at North Branch Raritan
River at South Branch (station 01400010), located just above the
confluence with South Branch Raritan River, used as auxiliary gage when
stage is above 3.40 ft to adjust for variable backwater. Some releases
from Round Valley Reservoir enter stream upstream from gage. Occasional
regulation due to gate operation at Ravine Lake, 13.8 mi
EXTREMES FOR PERIOD OF RECORD.--
Maximum discharge, 29,000
/s, Sep 16, 1999, gage height, 18.98 ft; minimum
discharge, 3.0 ft3
/s, Nov 28, 1930, as a result of probable
PERIOD OF RECORD.--
Water years 1923-25, 1960-76, 1978-80, 1997
to current year.
PERIOD OF DAILY RECORD.--
DISSOLVED OXYGEN: September 2009.
DISSOLVED OXYGEN, PERCENT OF SATURATION: September 2009. pH: September
2009. SPECIFIC CONDUCTANCE: September 2009. WATER TEMPERATURE:
Discrete water-quality data were collected as part of
New Jersey Ambient Surface-Water-Quality Monitoring Network
National Weather Service flood stage for this
gage is 10.0 ft.
Forecasts for this gage are issued by the National Weather Service
Forecast information is available here.