USGS Water-Year Summary 2023

01570500 SUSQUEHANNA RIVER AT HARRISBURG, PA

LOCATION - Lat 40°15'17", long 76°53'11" referenced to North American Datum of 1927, Dauphin County, PA, Hydrologic Unit 02050305, on east bank of City Island, 60 ft downstream from Market Street bridge in Harrisburg, 3,670 ft upstream from sanitary dam, and 1.7 mi upstream from Paxton Creek.

DRAINAGE AREA - 24,100 mi².

REVISIONS HISTORY - WSP 711: 1929. WSP 1502: 1891-1923, 1926(M), 1928. WSP 1702: 1953 (total runoff in inches), 1958 (1957 calendar year mean discharge).

SURFACE-WATER RECORDS

PERIOD OF RECORD - October 1890 to current year.

GAGE - Water-stage recorder. Concrete control since Aug 29, 1916. Datum of gage is 290.01 ft above National Geodetic Vertical Datum of 1929. Prior to Oct 1, 1928, non-recording gage at Walnut Street Bridge 600 ft upstream, and Oct 1, 1928, to Aug 31, 1975, water-stage recorder at site 3,170 ft downstream, all gages at same datum. Satellite and landline telemetry at station.

COOPERATION - Funding for the operation of this station is provided by Exelon Generation, the Pennsylvania Department of Environmental Protection, and the U. S. Geological Survey.

REMARKS - Flow slightly regulated by 15 flood-control reservoirs which have a combined capacity of 1,571,000 acre-ft. Records for water years 2014-2016 are good except those for estimated daily discharges, which are fair. Records for water years 2017-2021 are good except for estimated discharge, which is fair. Record for water year 2022 is good except for June 14 - Sept 30, which is fair, and estimated discharge, which is poor. Record for water year 2023 is good except for Oct 1 - Apr 6, which is fair, and estimated discharge, which is poor.

EXTREMES OUTSIDE PERIOD OF RECORD - Maximum stage known during period 1786 to 1890, 26.8 ft at Walnut Street bridge, Jun 2, 1889, discharge, 654,000 ft³/s.

WATER-QUALITY RECORDS

PERIOD OF RECORD - Water years 1944 to 1953, 1956 to 1995, 2008 to current year.

PERIOD OF DAILY RECORD - ON EASTERN BANK OF CITY ISLAND: WATER TEMPERATURE: October 1945 to August 1979; May 2008 to September 2011 (seasonal), October 2011 to March 2015. SPECIFIC CONDUCTANCE: May 1974 to August 1979; May 2008 to September 2011 (seasonal), October 2011 to December 2013. DISSOLVED OXYGEN: May 1974 to August 1979; May 2008 to September 2011 (seasonal), October 2011 to December 2013. pH: May 1974 to June 1979; May 2008 to September 2011 (seasonal), October 2011 to December 2013. IN EASTERN CHANNEL AT WALNUT STREET BRIDGE: WATER TEMPERATURE: July 2013 to current year (seasonal). SPECIFIC CONDUCTANCE: July 2013 to current year (seasonal). DISSOLVED OXYGEN: July 2013 to October 2015 (seasonal). pH: July 2013 to October 2015 (seasonal).

COOPERATION - Continuous daily water quality records were collected by the U.S. Geological Survey in cooperation with the Pennsylvania Department of Environmental Protection.

INSTRUMENTATION - ON EASTERN BANK OF CITY ISLAND: Water-quality monitor interfaced with a data collection platform with 30-minute recording interval (discontinued March 2015). IN EASTERN CHANNEL OF WALNUT ST BRIDGE: Water-quality monitor with 30-minute recording interval.

REMARKS -

ON EASTERN BANK OF CITY ISLAND: Records for 2014 water year have water temperature, pH, and dissolved oxygen records rated good. Specific conductance records rated fair.

IN EASTERN CHANNEL AT WALNUT STREET BRIDGE: Records for water year 2014 have water temperature rated excellent, specific conductance, pH, and dissolved oxygen records rated good, except specific conductance from July 2 through Aug 27, which is rated fair. Records for water year 2015 have water temperature rated excellent and pH and DO rated good. Specific conductance is rated good except for Aug 12 - Sept 16 which is rated fair, and May 6 - Aug 11 and Sept 17 - 30, which is rated poor. Records for water year 2016 have water temperature and specific conductance is rated poor. Records for water year 2017 have water temperature rated as good and specific conductance rated as poor. Records for water year 2018 have water temperature rated as fair and specific conductance rated as fair. Beginning in water year 2019, water quality records are not rated as "excellent", "good", "fair", or "poor". Water-quality parameters at this station can vary substantially at different locations in the river. Therefore, water-quality data displayed here characterizes conditions only at the location where water-quality equipment is deployed.

As of October 2013, results from discrete water quality samples collected at this site are available through the U.S. Geological Survey National Water Information System web interface on the "Water Quality for the Nation" webpage. Analyses for pH, water temperature, specific conductance, and dissolved oxygen were performed on site. Inorganic sample analyses were performed at the Pennsylvania Department of Environmental Protection laboratory in Harrisburg, PA. Occasionally, values for filtered parameters may exceed values for the corresponding unfiltered parameter. These results are within the limits of analytical precision and methods.

EXTREMES FOR PERIOD OF DAILY RECORD - SPECIFIC CONDUCTANCE: Maximum, 517 microsiemens/cm, Mar 4, 1978; minimum, 77 microsiemens/cm, Sep 27, 1975. Higher maximum values were published, but are considered unreliable. pH: Maximum, 10.4, Aug 27, 1975; minimum, 6.1, May 17, 1978. WATER TEMPERATURE: Maximum, 35.0°C, Jul 22, 2011; minimum, freezing point on many days during Jan and Feb, 1977. DISSOLVED OXYGEN: Maximum, 15.2 mg/L, Jan 23, 24, 1976; minimum 3.2 mg/L, Jul 8, 2011.