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SURFACE-WATER RECORDS
LOCATION.--Lat 40°28'30", long 74°34'33"
referenced to North American Datum of 1983, Hillsborough Township,
Somerset County, NJ, Hydrologic Unit 02030105, on left bank 30 ft
downstream from highway bridge on Blackwells Mills Causeway at
Blackwells Mills, 0.3 mi downstream from Six Mile Run, and 2.0 mi south
of Borough of Millstone.
DRAINAGE AREA.--258 mi
2.
PERIOD OF RECORD.--June 1903 to December 1904 (gage heights
only), August 1921 to current year. Monthly discharge only for some
periods, published in WSP 1302. Published as "at Millstone"
1903-04.
REVISED RECORDS.--WSP 1552: 1924-25(M), 1926. WDR US-2011: 1999,
2007, 2010.
GAGE.--Water-stage recorder with telemetry. Concrete control
since Nov 18, 1933. Datum of gage is 26.97 ft above NGVD of 1929. June
27, 1903 to Dec 31, 1904, non-recording gage at bridge 2.0 mi
downstream at Millstone at different datum. Aug 4, 1921 to Aug 16,
1928, non-recording gage at present site and datum.
REMARKS.--Records good, except for estimated discharges and
discharges greater than 2,000 ft
3/s, which are fair. Inflow
from and losses to Delaware and Raritan Canal upstream of station. Flow
slightly regulated by Carnegie Lake, capacity, 310,000,000 gal and
several smaller reservoirs, combined capacity, 49,800,000 gal.
EXTREMES FOR PERIOD OF RECORD.--Maximum discharge, 22,200
ft
3/s, Aug 28, 1971, gage height, 18.68 ft, from high-water
mark, maximum gage height, 21.24 ft, Aug 28, 2011, maximum discharge
occurred during different floodplain conditions; minimum discharge, 5.0
ft
3/s, Sep 16, 1923.
WATER-QUALITY RECORDS
PERIOD OF RECORD.--Water years 1962-69, 1973, 1976-80, 1991 to
current year.
REMARKS.--Discrete water-quality data were collected as part of
the
New Jersey Ambient Surface-Water-Quality Monitoring Network.
Peak
Flood Chart

National Weather Service flood stage for this
gage is 9.0 ft.
Forecasts for this gage are issued by the National Weather Service
routinely year-round.
Forecast information is available here.