USGS Water-Year Summary 2023

03075070 MONONGAHELA RIVER AT ELIZABETH, PA

LOCATION - Lat 40°15'44", long 79°54'05" referenced to North American Datum of 1927, Allegheny County, PA, Hydrologic Unit 05020005, on right bank 30 ft landward from upstream end of guide wall, and 1,050 ft upstream from dam at lock 3 at Elizabeth, 0.4 mi downstream from Lobbs Creek, at river mile 24.0.

DRAINAGE AREA - 5,340 mi².

REVISIONS HISTORY - WSP 758: Drainage area. WSP 783: 1888 (M). WSP 1435: 1934, 1936. See also "PERIOD OF RECORD."

SURFACE-WATER RECORDS

PERIOD OF RECORD - October 1933 to current year. Published as "at Charleroi" (station 03075000) October 1933 to September 1976. Monthly discharge prior to 1940, adjusted for reservoir contents, published in WSP 1305. Records for March 1886 to March 1905 (high-water periods only), published in WSP 169, are unreliable and should not be used. (Peak discharge of July 11, 1888, as published in WSP 183, is still considered reliable.)

GAGE - Water-stage recorder and concrete dam control. Datum of gage is 717.90 ft above National Geodetic Vertical Datum of 1929 (U.S. Army Corps of Engineers bench mark). From Oct. 1933 to Oct. 1, 1967, water-stage recorder at site 17.9 mi upstream at datum 17.43 ft higher. From Oct. 1, 1965 to Sept. 30, 1967, auxiliary staff gage and Apr. 14, 1966 to Sept. 30, 1967, auxiliary water-stage recorder at present site. From Oct. 1, 1967 to Sept. 30, 1976, at site 17.5 mi upstream at datum 15.70 ft higher. From Oct. 1, 1976 to Nov. 4, 1990, water-stage recorder at present site at datum 7.60 ft higher. Satellite telemetry at station.

COOPERATION - Station established and maintained by the U.S. Geological Survey. Funding for the operation of this station is provided by the U.S. Army Corps of Engineers, Pittsburgh District, the Pennsylvania Department of Environmental Protection, and the U.S. Geological Survey.

REMARKS - Flow regulated by locks/dams above station, since May 1926 by Lake Lynn, since 1938 by Tygart Lake, and since April 1989 by Stonewall Jackson Lake, combined capacity, 432,000 acre-ft.   Records are good except those for estimated discharge and below 5,000 cfs, which are poor.

WATER-QUALITY RECORDS

PERIOD OF RECORD - October 2010 to current year.

PERIOD OF DAILY RECORD - WATER TEMPERATURE: June 2005 to September 2008 (seasonal, May to October), October 2008 to current year. SPECIFIC CONDUCTANCE: June 2005 to September 2008 (seasonal, May to October) , October 2008 to current year. pH: June 2005 to September 2008 (seasonal, May to October),October 2008 to current year. DISSOLVED OXYGEN: June 2005 to current year(seasonal, May to October).

COOPERATION - Station established and maintained by the U.S. Geological Survey in cooperation with the U.S. Army Corps of Engineers, Pittsburgh District. Water-quality samples were collected as part of the Pennsylvania Department of Environmental Protection Water-Quality Network (WQN) with cooperation from the Pennsylvania Department of Environmental Protection.

INSTRUMENTATION - Continuous water-quality monitor interfaced with a data collection platform with 15-minute recording interval.

REMARKS -

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. All other 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.

Historically, water temperatures below 0 degrees Celsius were not reported. Water temperature sensors now have the ability to accurately read water temperatures below 0 degrees Celsius. 

Values reported by the monitor may not be representative of the entire river width. Cross-sectional water quality data is available upon request.

Dissolved oxygen data collected seasonally from May to October. Other interruptions in the record were due to malfunctions of the equipment. For water year 2014, water temperature, specific conductance, pH and dissolved oxygen records rated good. For water year 2015, records for water temperature, specific conductance, pH, and dissolved oxygen are rated good. For water year 2016, records for water temperature, specific conductance, pH, and dissolved oxygen are rated good. For water year 2017, records for water temperature, specific conductance, pH, and dissolved oxygen are rated good. For water year 2018, records for water temperature are rated good, except for April 18 to June 18, which are fair. Records for specific conductance, pH, and dissolved oxygen are rated good, except for April 18 to June 18, which are fair. 

For water year 2019, records for water temperature are rated good, Records for specific conductance are rated good, except for  October 18 to Novevember 19 and , March 25 to April 19,  which are rated fair.  pH records are rated good, except for March 23-25 and June 24 to September 30, which are fair.  Dissolved oxygen records are rated good, except for June 24 to September 30, which are fair.

EXTREMES FOR PERIOD OF DAILY RECORD - WATER TEMPERATURE: Maximum, 34.9°C, Jul 7, 2010; minimum, -0.4°C, several days in January and February 2014 SPECIFIC CONDUCTANCE: Maximum, 1290 microsiemens/cm, Nov 8, 9, 2008; minimum, 137 microsiemens/cm, January 4, 2022.  pH: Maximum, 8.6 standard units, Sep 11, 2013; minimum, 6.8 standard units, June 17, 2012 and July 30, 2017.  DISSOLVED OXYGEN:  Maximum: 12.1 mg/l, September 11, 2013.  Minimum: 4.1 mg/l, July 14,17, 2012.