USGS Water-Year Summary 2024
09474000 GILA RIVER AT KELVIN, AZ
LOCATION - Lat 33°06'10", long 110°58'33" referenced to North American Datum of 1927, in NE 1/4 NW 1/4 sec.12, T.4 S., R.13 E., Pinal County, AZ, Hydrologic Unit 15050100, on left bank at Kelvin, 500 ft downstream from Mineral Creek, 18 mi downstream from San Pedro River, and 19 mi upstream from Ashurst-Hayden Dam.
DRAINAGE AREA - 18,011 mi², 12,866 mi² being above Coolidge Dam, and 5,125 mi² below Coolidge Dam (696 mi² of this area are in Mexico)
SURFACE-WATER RECORDS
PERIOD OF RECORD - Jan. 1911 to current year.
REVISED RECORDS - WSP 329: 1911. WSP 609: 1916(M). WSP 629: 1914-17. WSP 1119: 1913, 1915, 1917(M), 1921(M), 1922-23, 1927(M). WSP 1283: Drainage Area.
GAGE - Water-stage recorder. Datum of gage is 1,745.02 ft above sea level. Prior to June 15, 1914, and Dec. 1, 1914, to Aug. 31, 1915, nonrecording gages at several sites within 2 mi of present site at different datums. Sept. 1, 1915, to Sept. 30, 1963, water-stage recorder at site 900 ft downstream at datum 1.80 ft lower. Jan. 16, 1985, to June 1990, supplementary water-stage recorder at same site and datum.
EXTREMES FOR PERIOD OF RECORD - 1911-28: Maximum discharge, about 132,000 ft³/s, Jan. 20, 1916, gage height, 19.5 ft, site and datum then in use, from rating curve extended above slope-area measurement at gage height, 16.2 ft for flood of Sept. 28, 1926; minimum, no flow, Feb. 25, 1913.
1929-Current year: Maximum discharge, 100,000 ft³/s, Oct. 2, 1983, gage height, 33.0 ft from floodmark, from rating curve extended above 12,000 ft³/s on basis of peak discharge computed by step-backwater method at Hayden Railroad Bridge, 17.8 mi upstream, and by flood-routing; minimum daily, no flow for many days in most years.
AVERAGE DISCHARGE FOR PERIOD OF RECORD - (adjusted for storage in San Carlos Reservoir) 103 years, 490 ft³/s, 354,700 acre-ft/yr; median of yearly mean discharges, 296 ft³/s, 214,000 acre-ft/yr.
WATER-QUALITY RECORDS
PERIOD OF RECORD - Dec. 1950 to Sept. 1994, Feb. 1996 to Feb. 1998, Sept. 2001 to June 2006 (discontinued).
PERIOD OF DAILY RECORD -
SPECIFIC CONDUCTANCE:Oct. 1964 to Sept. 1976, Oct. 1996 to Feb. 1998.
WATER TEMPERATURE:Dec. 1950 to Sept. 1976, Oct. 1996 to Feb. 1998.
SUSPENDED-SEDIMENT DISCHARGE:Jan. 1958 to Sept. 1976.