Warning: Javascript must be enabled to use all the features on this page!

Page Loading - Please Wait...

Click to hideNews Bulletins
  • Data formats changed in August 2016, and additional water-data changes will be coming through 2017. Read more here
  • Full News RSS icon
Click to hide state-specific text


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 analysis.

USGS 01402000 Millstone River at Blackwells Mills NJ


Click to hidestation-specific text

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.

gage photo 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 at Blackwells Mills, and 0.3 mi downstream from Six Mile Run.
DRAINAGE AREA.--258 mi2.
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.
GAGE.--Water-stage recorder. Concrete control since Nov. 18, 1933. Datum of gage is 26.97 ft above NGVD of 1929. June 27, 1903 to Dec. 31, 1904, nonrecording gage at bridge 2.0 mi downstream at Millstone at different datum. Aug. 4, 1921 to Aug. 16, 1928, nonrecording gage at present site and datum.
COOPERATION.--Funding for this gage is provided by the New Jersey Water Supply Authority, the New Jersey Department of Environmental Protection, and the U.S. Geological Survey.

Boating safety tips

This station managed by the New Jersey Water Science Center.

Available Parameters Available Period
All 2 Available Parameters for this site
00060 Discharge 2007-10-01  2016-08-26
00065 Gage height, H350XL Bubbler 2014-05-16  2016-08-26

Graph w/ stats
Graph w/o stats
Graph w/ (up to 3) parms
Days  (7)

  -- or --
Begin date

End date

Summary of all available data for this site
Instantaneous-data availability statement

Most recent instantaneous value: 51   08-26-2016   05:15 EDT
Graph of  Discharge, cubic feet per second

Add up to 2 more sites and replot for "Discharge, cubic feet per second"

 Add site numbers

Create presentation-quality / stand-alone graph.   Subscribe to WaterAlert      

Daily discharge, cubic feet per second -- statistics for Aug 26 based on 94 years of record more
Most Recent
Value Aug 26
Median Mean 75th
10 51 58 101 161 183 1160

Most recent instantaneous value: 1.55   08-26-2016   05:15 EDT
Graph of  Gage height, feet, H350XL Bubbler

Add up to 2 more sites and replot for "Gage height, feet, H350XL Bubbler"

 Add site numbers

Create presentation-quality / stand-alone graph.   Subscribe to WaterAlert