USGS Water-Year Summary 2021
09426000 BILL WILLIAMS RIVER BELOW ALAMO DAM, AZ
LOCATION - Lat 34°13'51", long 113°36'29" referenced to North American Datum of 1927, in SE 1/4 SE 1/4 sec.04, T.10 N., R.13 W., La Paz County, AZ, Hydrologic Unit 15030204, on left bank 0.6 mi downstream from Alamo Dam, 3.7 mi downstream from Bullard Wash, and 8 mi downstream from confluence of Santa Maria and Big Sandy Rivers.
DRAINAGE AREA - 4,633 mi² of which 10 mi² probably is noncontributing.
- WSP 1213: 1939(M). 1941(P). WDR AZ-89-1: Drainage area. WDR AZ-10-1: 2005.
PERIOD OF RECORD - Oct. 1939 to current year. Monthly discharge only for Oct. and Nov. 1939, published in WSP 1313. Prior to Oct. 1943, published as "Williams River near Alamo." Oct. 1943 to Sept. 1967, published as "Bill Williams River near Alamo."
GAGE - Water-stage recorder. Elevation of gage is 967 ft above sea level, from construction data. Prior to Apr. 9, 1968, at site 1.7 mi upstream at datum 1,002.95 ft above sea level.
EXTREMES OUTSIDE PERIOD OF RECORD - The history of floods that occurred prior to Oct. 1939 is published in WSP 1683. The peak discharges have been correlated with those for Bill Williams River at Planet. The peak discharge for Feb. 1937 has been determined as 105,000 ft³/s at a stage of 46 ft, site and datum then in use, from rating curve extended above 50,000 ft³/s on basis of slope-area measurement for flood of Sept. 6, 1939, at a stage of 39.6 ft, discharge of 86,000 ft³/s and known stable highwater control.
EXTREMES FOR PERIOD OF RECORD - 1940-1968: Maximum discharge, 65,100 ft³/s, Aug. 29, 1951, gage height, 30.8 ft, site and datum then in use; minimum daily, 1.1 ft³/s, Sept. 4, 1958.
1969-2010: Maximum discharge, 6,980 ft³/s, Mar. 16, 22, 1993, gage height, unknown as weir had washed out; minimum, no flow at times in most years.