USGS Water-Year Summary 2023

03036000 MAHONING CREEK AT MAHONING CREEK DAM, PA

LOCATION - Lat 40°55'39", long 79°17'29" referenced to North American Datum of 1927, Armstrong County, PA, Hydrologic Unit 05010006, on left bank at downstream side of highway bridge at McCrea Furnace, 700 ft downstream from Camp Run, 0.9 mi downstream from Mahoning Creek Dam, 1 mi southwest of Eddyville, and 2.1 mi upstream from Pine Run.

DRAINAGE AREA - 344 mi².

REVISIONS HISTORY - Revisions: Prior to November 2, 2023, the datum of gage was erroneously reported as 1003.39 ft above National Geodetic Vertical Datum of 1929.

SURFACE-WATER RECORDS

PERIOD OF RECORD - August 1938 to January 1941 (non-recording gage), February 1941 to September 1991, October 2004 to September 2009 (discharge measurements only), October 2009 to current year.

GAGE - Water-stage recorder. Datum of gage is 1,002.2 ft above North American Vertical Datum of 1988.  Prior to November 2, 2023, the datum of gage was erroneously reported as 1,003.39 ft above National Geodetic Vertical Datum of 1929.  Satellite telemetry at station.

COOPERATION - Station established and maintained by the U.S. Geological Survey. Funding for this station is provided by the U.S. Army Corps of Engineers, Pittsburgh District, and Mahoning Creek Hydroelectric Company, LLC.

REMARKS - Discharge regulated since 1941 by Mahoning Creek Reservoir (03035500), 0.9 mi upstream.  Records are good except those for estimated discharge, which are poor.

WATER-QUALITY RECORDS

PERIOD OF RECORD - November 1975 to August 1976; August 2009 to current year.

PERIOD OF DAILY RECORD - SPECIFIC CONDUCTANCE: October 2008 to current year. pH: October 2008 to current year. WATER TEMPERATURE: October 2007 to current year. DISSOLVED OXYGEN: October 2008 to September 2015 (seasonal operation, June to October), October 2016 to current year. TOTAL DISSOLVED GAS: October 2010 to October, 2018 (seasonal operation, June to October). AIR PRESSURE: October 2010-October, 2018 (seasonal operation, June to October).

COOPERATION - 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 -

Water temperature monitor since October 2007. Water-quality monitor (consisting of specific conductance, pH, dissolved oxygen, and water temperature since October 2008; total partial pressure of dissolved gas added in October 2010; data collected seasonally until October, 2018). Data collected by the monitor may not be representative of the entire stream width.

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. 

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

Data collection is suspended from November through April for dissolved oxygen and total dissolved gas pressure. Other interruptions in the record were due to equipment malfunctions.

For water year 2014, records for water temperature, specific conductance, and dissolved oxygen are rated good. Records for pH are rated good, except for November 1 to January 15, which are rated fair. Records for total dissolved gas pressure are rated fair, except for July 16 to August 28, which are rated poor.

For water year 2015, records for water temperature and pH are rated good. Records for specific conductance are rated good, except for September 28-30, which are rated fair, and October 21 to November 5, which are rated poor. Records for dissolved oxygen are rated good, except for August 24-28, which are rated fair, and August 2-9 and August 29 to September 7, which are rated poor. Records for total dissolved gas are rated good, except for August 23 to September 31, which are fair, and May 1-28, which are poor. 

 For water year 2017, records for water temperature and specific conductance are rated good. Records for dissolved oxygen are rated good, except for November 30 to May 8, which are fair. Records for pH are rated good, except for September 13-18, which are fair. Records for barometric pressure are accurate within +/- 2 mmHg. Records for total partial pressure of dissolved gas are accurate to +/- 2% of total saturation.

For water year 2018, records for water temperature, specific conductance, and dissolved oxygen, are rated good. Records for pH are rated good, except for September 20-30, which are fair, and January 24 to April 10 and July 8-13, which are poor. Records for barometric pressure are accurate within +/- 2 mmHg. Records for total partial pressure of dissolved gas are accurate to +/- 2% of total saturation.

Beginning in water year 2019, water quality records are not rated as "excellent", "good", "fair", or "poor".

EXTREMES FOR PERIOD OF DAILY RECORD - SPECIFIC CONDUCTANCE: Maximum, 598 microsiemens/cm, October 1, 2010; minimum, 104 microsiemens/cm, Sep 14, 2018. pH: Maximum, 8.7 units, Oct 12, 2009 and several days in 2011 water year; minimum, 5.8 units, Jan 8, 2019. WATER TEMPERATURE: Maximum, 28.7°C, August 22, 2020; minimum, -0.4°C, several days during winters.