LOCATION.--Lat 41°39'07.9", long
73°56'57.2" referenced to North American Datum of
1983, Dutchess County, NY, Hydrologic Unit 02020008, on left
bank at IBM pumping station, 2.3 mi south of Poughkeepsie, and
3.5 mi south of the Mid-Hudson bridge.
DRAINAGE AREA.--11,876 mi².
PERIOD OF RECORD.--March 2002 to September 2019. Daily
elevations published since May 1992. Occasional miscellaneous
discharge measurements, water year 2001.
REVISIONS HISTORY.--WDR NY-97-1: 1996. Drainage
area was revised on Aug. 30, 2023, from 11,740 sq mi to 11,876
sq mi, based on better definition methods.
GAGE.--Water-stage recorder and acoustic velocity meter.
Datum of gage is NGVD of 1929. To convert elevations to NAVD of
1988, subtract 0.88 ft.
REMARKS.--Flow at this site is affected by astronomical
tides. Prior to September 2012, discharge computed with an
uplooking acoustic velocity meter. Since September 2012,
discharge computed with a sidelooking acoustic velocity meter.
Blanks in discharge tables, July to October 2002 and July to
October 2007, are the result of the salt front adversely
affecting measured velocity. All other blanks in discharge
tables are due to interruption of record. Prior to October
2002, elevation published as maximum, minimum, and mean
elevation. Elevations are not corrected for changes in water
density. Blanks in elevation tables are the result of only one
high or low tide during a day or interruption of record. Water
Years 2014-19: Records fair except those for estimated daily
discharge, which are poor.
EXTREMES FOR PERIOD OF RECORD.--Maximum daily discharge,
240,000 ft³/s, Aug. 29, 2011; maximum elevation recorded, 9.54
ft, Oct. 29, 2012, but may have been higher during period of
instrument malfunction, outside elevation was 9.28 ft, from
floodmarks; minimum daily discharge, -24,900 ft³/s, Oct. 14,
2003, but may have been lower during period of missing record;
minimum elevation, -4.38 ft, Mar. 14, 15, 1993.
PERIOD OF DAILY RECORD1.--SPECIFIC
CONDUCTANCE: May 1992 to November 2019. WATER TEMPERATURE: May
1992 to November 2019.
specific-conductance satellite and telephone telemeter provides
REMARKS1.--Temperature readings prior to Oct.
1, 2007, rounded to the nearest 0.5 °C. Specific conductance
occasionally affected by local runoff.
EXTREMES FOR PERIOD OF DAILY
RECORD1.--SPECIFIC CONDUCTANCE: Maximum, 2,900
Ã¬S/cm at 25 °C, Sept. 8, 2002; minimum, 96 Ã¬S/cm at 25 °C,
Jan. 30, 1995.
WATER TEMPERATURE: Prior to Oct. 1, 2007--Maximum, 29.0 °C,
Aug. 14, 2005; minimum, 0.0 °C on many days during winter
periods, except 2002.
WATER TEMPERATURE: After Oct. 1, 2007--Maximum, 28.6 °C, Aug.
13, 14, 2016; minimum, -0.2 °C, Feb. 6, 7, 2010, several days
during February 2011 and 2014 winter period.
1 Water-Quality Records