USGS Water-Year Summary for Site 021720869

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	Available Parameters
	00010 Temperature, water(Max.,Min.,Mean)
	00065 Gage height(Max.,Min.,Mean)
	00095 Specific cond at 25C(Max.,Min.,Mean)
	00300 Dissolved oxygen(Max.,Min.,Mean)

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Water year 2024: 2024-10-01 to 2025-09-30

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USGS Water-Year Summary 2024

021720869 ASHLEY RIVER NEAR NORTH CHARLESTON, SC

LOCATION - Lat 32°50'04", long 80°01'26" referenced to North American Datum of 1927, Charleston County, SC, Hydrologic Unit 03050202, on downstream side of bridge on Interstate 526, 1.5 mi south of North Charleston, and at mile 9.8.

DRAINAGE AREA - Indeterminate

SURFACE-WATER RECORDS

PERIOD OF RECORD - July 1992 to September 1995, April 2004 to current year.

GAGE - Data collection platform. Elevation of gage is 8.57 ft below NAVD of 1988.

EXTREMES FOR PERIOD OF RECORD - Maximum gage height, 15.58 ft, September 11, 2017; minimum gage height, 2.28 ft, Mar. 8, 2008.

WATER-QUALITY RECORDS

PERIOD OF RECORD - Water years 1992 to 1995, 2004 to current year.

PERIOD OF DAILY RECORD -
SPECIFIC CONDUCTANCE (TOP): July 1992 to September 1995, March 2004 to May 2005 (discontinued).
SPECIFIC CONDUCTANCE (MIDDLE): May 2005 to April 2009, July 2009 to current year.
SPECIFIC CONDUCTANCE (BOTTOM): July 1992 to September 1994, March 2004 to May 2005 (discontinued).
SALINITY (TOP): March 1993 to September 1995 (discontinued).
SALINITY (BOTTOM): April 1993 to September 1994 (discontinued).
WATER TEMPERATURE (TOP): July 1992 to September 1995, March 2004 to May 2005 (discontinued).
WATER TEMPERATURE (MIDDLE): May 2005 to April 2009, July 2009 to current year.
WATER TEMPERATURE (BOTTOM): July 1992 to September 1994, March 2004 to May 2005 (discontinued).
DISSOLVED OXYGEN (TOP): July 1992 to September 1995, March 2004 to May 2005 (discontinued).
DISSOLVED OXYGEN (MIDDLE): May 2005 to April 2009, July 2009 to current year.
DISSOLVED OXYGEN (BOTTOM): July 1992 to September 1994, March 2004 to May 2005 (discontinued).

INSTRUMENTATION - Water-quality multiprobe and data collection platform.

REMARKS -
Sensor location"Top" is set to 3.0 ft below the water surface at all tide phases.
Sensor location "Middle" is static and set at gage height= -2.4 ft.
Sensor location "Bottom" is static and set at unknown gage height.

For the 2014 water year, specific Conductance (MIDDLE) records rated good. 
For the 2014 water year, temperature (MIDDLE) records rated excellent. 
For the 2014 water year, dissolved oxygen (MIDDLE) records rated good. 

For the 2015 water year, specific Conductance (MIDDLE) records rated good except for Feb. 10 - Mar. 30
and Jun. 4 - Jul. 28, which are rated fair. 
For the 2015 water year, temperature (MIDDLE) records rated excellent. 
For the 2015 water year, dissolved oxygen (MIDDLE) records rated good. 

For the 2016 water year, specific Conductance (MIDDLE) records rated excellent except for Dec. 15 to
Apr. 26, May 16 to Jul. 15, Aug. 25 to Sept. 30, which are good, Jun. 21 to Aug. 24, which are poor.
For the 2016 water year, temperature (MIDDLE) records rated excellent. 
For the 2015 water year, dissolved oxygen (MIDDLE) records rated excellent except for Oct. 1-6, 
Apr.27 to Jun. 13, which are rated good. 

Prior to October 1, 2003 dissolved oxygen concentrations are not corrected for salinity.

EXTREMES FOR PERIOD OF DAILY RECORD -
SPECIFIC CONDUCTANCE (MIDDLE): Maximum, 44,600 microsiemens/cm, July 25, 2006; minimum, 68 microsiemens/cm, Oct. 9, 2015.
WATER TEMPERATURE (MIDDLE): Maximum, 32.7°C, July 28, 2005, July 26, 2010; minimum, 2.5°C, Jan. 8, 2018.
DISSOLVED OXYGEN (MIDDLE): Maximum, 12.7 mg/L, Jan. 16, 2011; minimum, 1.4 mg/L, Jun. 22, 2018, Jun. 29, 2018.