USGS Water-Year Summary 2024
08159500 Colorado River at Smithville, TX
LOCATION - Lat 30°00'45", long 97°09'42" referenced to North American Datum of 1927, Bastrop County, TX, Hydrologic Unit 12090301, on right bank 28 ft downstream from bridge on Business State Highway 71 in Smithville, 500 ft below mouth of Gazley Creek, 3.9 mi below mouth of Alum Creek, and at mile 212.1.
DRAINAGE AREA - 40,371 mi² of which 11,403 mi² probably is noncontributing.
REVISIONS HISTORY - WSP 1342: Drainage area. WSP 1562: 1934. WSP 1712: 1953, 1954(M), 1957-58.
SURFACE-WATER RECORDS
PERIOD OF RECORD - July 1930 to Sept. 1975, Oct. 1997 to current year.
PERIOD OF RECORD, Water-Quality.--
CHEMICAL DATA: Nov. 1973 to Aug. 1975, Feb. 2001.
BIOCHEMICAL DATA: Oct. 1973 to Sept. 1975.
GAGE -
Water-stage recorder. Radio and Satellite telemetry at station.
Datum of gage: 270.146 ft NAVD88 based on a Level 2 Static GNSS survey processed through OPUS, Ref Frame NAD83 (2011)(EPOCH:2010.0000) ITRF2014 (EPOCH:2023.6240) and Geoid18. The survey was completed on August 16, 2023, while occupying gage origin RM7.
Prior to 8/16/2023: the datum of the gage was 270.14 ft NGVD29. Prior to Apr. 9, 1931, nonrecording gage at same site and datum. Apr. 9, 1931, to Sept. 2, 1971, water-stage recorder at site 360 ft downstream at same datum.
COOPERATION - Lower Colorado River Authority provides operation and maintenance of the gage and verification of stage-discharge relation at low stages. U.S. Geological Survey maintains stage-discharge relation at medium to high stages, computes, and publishes streamflow record.
EXTREMES OUTSIDE PERIOD OF RECORD - Maximum stage since at least 1860, occurred July 8, 1869, and was several feet higher than flood of Dec. 4, 1913, which reached a stage of 47.4 ft and was the highest since 1869, from information by local residents.