USGS Water-Year Summary for Site 08121000

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	Available Parameters
	00060 Discharge(Max.,Min.,Mean)
	00065 Gage height(Max.,Min.,Mean)

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Water year 2024: 2023-10-01 to 2024-09-30

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USGS Water-Year Summary 2024

08121000 Colorado River at Colorado City, TX

LOCATION - Lat 32°23'33", long 100°52'42" referenced to North American Datum of 1927, Mitchell County, TX, Hydrologic Unit 12080002, on right bank at Colorado City, 3,517 ft upstream from bridge on State Highway 377, 4,100 ft upstream from the Texas and Pacific Railroad Company bridge, 1.3 mi downstream from bridge on Interstate Highway 20 and U.S. Highway 80, 1.6 mi upstream from Lone Wolf Creek, and at mile 796.3.

DRAINAGE AREA - 3,966 mi² of which 2,381 mi² probably is noncontributing.

REVISIONS HISTORY - WSP 1512: 1946(M). WDR TX-81-3: Drainage area.

SURFACE-WATER RECORDS

PERIOD OF RECORD - Nov. 1923 to Aug. 1925 (published as "at Colorado"), May 1946 to current year. PERIOD OF RECORD, Water-Quality.-- CHEMICAL DATA: May 1946 to Sept. 1954, Nov. 1956 to Oct. 2003. BIOCHEMICAL DATA: July 1960 to Sept. 1973. RADIOCHEMICAL DATA: Jan. 1981 to May 1981. PERIOD OF DAILY RECORD, Water-Quality.-- SPECIFIC CONDUCTANCE: May 1946 to Sept. 1954, Nov. 1956 to Sept. 2004. WATER TEMPERATURE: Nov. 1952 to Sept. 1954, Nov. 1956 to Sept. 2004.

GAGE - Water-stage recorder. Datum of gage is 2,030.79ft above NAVD88 as determined by GNSS survey. Prior to March 24, 2020, the datum of the gage was 2,030.16ft above NGVD29. Nov. 28, 1923, to Aug. 31, 1925, nonrecording gage at site 1.4 mi downstream at different datum. May 9 to Aug. 5, 1946, nonrecording gage at site 185 ft upstream at present datum. Satellite telemeter at station.

COOPERATION - Texas Water Development Board, TWDB, and the U.S. Geological Survey, USGS.

REMARKS - Since water year 1952, at least 10% of contributing drainage area has been regulated. The Colorado River Municipal Water District diverts low flow into an off channel reservoir 3 miles upstream for brine disposal. There are numerous diversions from Lake J.B. Thomas for municipal use and oil field operations. No flow at times. Some records listed in the period of record may not be available electronically.

EXTREMES OUTSIDE PERIOD OF RECORD - Maximum stage since at least 1910, 35.9 ft, June 20, 1939, present site and datum, based on floodmarks 1,000 ft upstream and 3,740 ft downstream from gage; discharge, 66,000 ft³/s, by slope-area measurement of peak flow at site 2.5 mi upstream from gage.

EXTREMES FOR PERIOD PRIOR TO REGULATION - WATER YEARS 1947-1951: Maximum discharge, 24,900 ft³/s, July 6, 1948, gage height, 22.37 ft, from floodmark; no flow at times.

AVERAGE DISCHARGE FOR PERIOD PRIOR TO REGULATION - 5 years (water years 1947-51) prior to completion of Lake J.B. Thomas, 102 ft³/s (73,660 acre-ft/yr).

WATER-QUALITY RECORDS

PERIOD OF RECORD - CHEMICAL DATA: May 1946 to Sept. 1954, Nov. 1956 to Oct. 2003. BIOCHEMICAL DATA: July 1960 to Sept. 1973. RADIOCHEMICAL DATA: Jan. 1981 to May 1981. PERIOD OF DAILY RECORD, Water-Quality.-- SPECIFIC CONDUCTANCE: May 1946 to Sept. 1954, Nov. 1956 to Sept. 2004. WATER TEMPERATURE: Nov. 1952 to Sept. 1954, Nov. 1956 to Sept. 2004.