USGS Water-Year Summary for Site 07381490

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	Available Parameters
	00060 Discharge(Mean)
	00065 Gage height(Mean)

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Water year 2023: 2022-10-01 to 2023-09-30

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USGS Water-Year Summary 2023

07381490 Atchafalaya River at Simmesport, LA

LOCATION - Lat 30°58'57", long 91°47'54" referenced to North American Datum of 1983, Avoyelles Parish, LA, Hydrologic Unit 08080101, Lat N30'58'51.05'', Long W91'47'49.56'' Located on railroad bridge in Simmsport over the Atchafalaya river Approx 200 yards North West of Operators Shack. Gage is mounted on downstream side of railroad bridge on handrail.

DRAINAGE AREA - 87,570 mi².

REVISIONS HISTORY - Parameter codes 80154 (suspended sediment concentration, mg/L), 80155 (suspended sediment discharge, tons/day), and 70331 (suspended sediment sieve diameter percent <0.0625 mm) were revised in November 2018, as described in USGS SIR 2018-5147 (https://pubs.er.usgs.gov/publication/sir20185147) for the period Oct. 4, 1989 to February 3, 2015.

SURFACE-WATER RECORDS

PERIOD OF RECORD - November 13, 2009 to current year.

GAGE - Water-stage recorder. Datum of gage is 0.00 ft NGVD 29.

COOPERATION - United States Corps of Engineers, New Orleans District

REMARKS - Discharge records good except for periods of estimated data which are poor.

EXTREMES FOR PERIOD OF RECORD - Maximum discharge, 697,000 ft³/s, May. 23, 24 2011, gage height, 45.06 ft; minimum discharge, 44,700 ft³/s, Oct. 29, 2012, gage height, 3.00 ft.

WATER-QUALITY RECORDS

PERIOD OF RECORD - Water years 1952-53, 1973 to current year.

PERIOD OF DAILY RECORD - SPECIFIC CONDUCTANCE: October 1974 to September 1975, October 1978 to September 1979. WATER TEMPERATURE: December 1975 to September 1976, October 1977 to September 1984, May 1990 to August 1992. CHLORIDE: October 1974 to September 1984, May 1990 to August 1992. SUSPENDED-SEDIMENT DISCHARGE: October 1972 to current year.

COOPERATION - United States Corps of Engineers, New Orleans District.

EXTREMES FOR PERIOD OF DAILY RECORD - SPECIFIC CONDUCTANCE: Maximum daily, 627 micromhos Nov. 17, 1978; minimum daily, 179 micromhos Feb. 21, 1979. WATER TEMPERATURE: Maximum daily, 32.0°C July 23, 1981; minimum daily, 2.0°C Jan. 18-20, Feb. 3, 6, 7, 1978, Jan. 15, 1979, Jan. 14, 1982. CHLORIDE: Maximum daily, 150 mg/L June 9, 13, 14, 1977; minimum daily, 9.1 mg/L May 14, 1991. SUSPENDED-SEDIMENT DISCHARGE: Maximum daily, 1,240,000 tons Dec. 15, 1982; minimum daily, 2,000 tons Oct. 3- 5, 1976.