LOCATION.--Lat 41°23'10", long
73°57'20" referenced to North American Datum of 1927,
Orange County, NY, Hydrologic Unit 02020008, on right bank 1.2
mi upstream of Highland Brook at South Dock at West Point, New
York.
DRAINAGE AREA.--12,596 mi².
PERIOD OF RECORD.--October 1991 to February 2012, June
2013 to September 2014. Records for June 1989 to September 1991
are unpublished and available in files of the Geological
Survey.
GAGE.--Water-stage recorder. Datum of gage is NGVD of
1929.
REMARKS.--Prior to October 2002 published as maximum,
minimum, and mean elevation. Elevations are not corrected for
changes in water density. Blanks in tables are the result of
only one high or low tide during a day or interruption of
record.
EXTREMES FOR PERIOD OF RECORD.--Maximum elevation, 7.65
ft, Aug. 28, 2011; minimum elevation, -4.26 ft, Mar. 14,
1993.
EXTREMES OUTSIDE PERIOD OF RECORD.--Flood of Oct. 29,
2012, reached an elevation of 9.60 ft, from floodmark.
PERIOD OF RECORD1.--October 1991 to February
2012, June 2013 to September 2014, April 2019 to current
year.
PERIOD OF DAILY RECORD1.--WATER TEMPERATURE
AT 9 FT BELOW NAVD: October 1991 to February 2012, June 2013 to
September 2014. Records for February 1990 to September 1991 are
unpublished and available in files of the Geological Survey.
WATER TEMPERATURE [HRECOS]: April 2019 to current year.
SPECIFIC CONDUCTANCE AT 9 FT BELOW NAVD: October 1991 to
February 2012, June 2013 to September 2014. Records for
February 1990 to September 1991 are unpublished and available
in files of the Geological Survey. SPECIFIC CONDUCTANCE
[HRECOS]: April 2019 to current year.
SALINITY [HRECOS]: April 2019 to current year.
pH AT 9 FT BELOW NAVD: June 2013 to September 2014. pH
[HRECOS]: April 2019 to current year.
DISSOLVED OXYGEN AT 9 FT BELOW NAVD: June 2013 to September
2014. DISSOLVED OXYGEN [HRECOS]: April 2019 to current
year.
TURBIDITY AT 9 FT BELOW NAVD: June 2013 to September 2014.
TURBIDITY [HRECOS]: April 2019 to current year.
INSTRUMENTATION1.--A continuous water-quality
monitor with water temperature, specific conductance, pH,
dissolved oxygen and turbidity provides 15-minute-interval
readings. Salinity record computed from
specific-conductance readings.
REMARKS1.--Temperature readings prior to Oct.
1, 2007, rounded to nearest 0.5 °C.
COOPERATION1.--April 2019 to current year:
Maintained by the Hudson River Environmental Conditions
Observing System in cooperation with the Cary Institute of
Ecosystem Studies.
EXTREMES FOR PERIOD OF DAILY RECORD1.--WATER
TEMPERATURE AT 9 FT BELOW NAVD: Prior to Oct. 1, 2007--Maximum,
29.0°C, Aug. 12, 13, 14, 2005; minimum, 0.0°C, on many days
during winter periods, except 1998, 2002. After Oct. 1,
2007--Maximum, 28.2°C, July 24, 27, 2010; minimum, -0.2°C on
many days during 2009 winter period. WATER TEMPERATURE
[HRECOS]: Maximum, 29.0°C, Aug. 3, 2020; minimum -0.5°C, on
several days during 2022 winter period.
SPECIFIC CONDUCTANCE AT 9 FT BELOW NAVD: Maximum, 12,600 uS/cm
@ 25°C, Sept. 23, 1995; minimum, 102 uS/cm @ 25°C, May 30,
1996. SPECIFIC CONDUCTANCE [HRECOS]: Maximum, 11,000 uS/cm @
25°C, Sept. 16, 2020, minimum, 162 uS/cm @ 25°C, May 2, 3,
2019.
SALINITY [HRECOS]: Maximum, 6.2 psu, Sept. 16, 2020, minimum,
0.1 psu, May 2, 3, 2019.
pH AT 9 FT BELOW NAVD: Maximum, 8.0, Sept. 26, 27, 2013,
several days during 2014; minimum, 7.3, several days during
2014. pH [HRECOS]: Maximum, 8.6, May 30, 31, 2020; minimum,
7.2, May 5, 6, 7, 2019.
DISSOLVED OXYGEN AT 9 FT BELOW NAVD: Maximum, 15.2 mg/L,
several days during January 2014; minimum, 5.8 mg/L, July 21,
22, 23, 24, 2013. DISSOLVED OXYGEN [HRECOS]: Maximum, 14.9
mg/L, Jan. 21, 2022; minimum, 4.9 mg/L Aug. 17, 21,
2020.
TURBIDITY AT 9 FT BELOW NAVD: Maximum, 230 FNU, Sept. 9, 2014;
minimum, 2.4 FNU, Oct. 2, 2013. TURBIDITY [HRECOS]: Apr. 25,
2019 to Aug. 18, 2022: Maximum, 174 FNU, Feb. 9, 2020, minimum,
1.2 FNU, June 20, 2020.
1 Water-Quality Records