USGS Water-Year Summary 2020
08151500 Llano River at Llano, TX
LOCATION - Lat 30°45'04", long 98°40'10" referenced to North American Datum of 1927, Llano County, TX, Hydrologic Unit 12090204, on right bank in Llano, 0.4 mi downstream from bridge on State Highway 16, 7.0 mi upstream from Little Llano River, and 29.3 mi upstream from mouth.
DRAINAGE AREA - 4,197 mi² of which 5 mi² probably is noncontributing.
- WDR TX-81-3: Drainage area.
PERIOD OF RECORD - Sept. 1939 to current year.
PERIOD OF RECORD, Water-Quality.--
CHEMICAL DATA: Apr. 1948 to Oct. 1967, Apr. 1979 to Aug. 1986.
BIOCHEMICAL DATA: Apr. 1979 to Aug. 1986.
BIOLOGICAL DATA: Apr. 1979 to Aug. 1986.
SEDIMENT DATA: Sept. 1964, Apr. 1979 to Aug. 1986.
RADIOCHEMICAL DATA: Mar. to July 1981.
TAXONOMIC DATA: May 1979 to Sept. 1981.
PERIOD OF DAILY RECORD, Water-Quality.--
SPECIFIC CONDUCTANCE: Apr. 1979 to Sept. 1980.
WATER TEMPERATURE: Apr. 1979 to Sept. 1980.
GAGE - Water-stage recorder. Datum of gage is 970.01 ft above NGVD of 1929. Radio telemeter at station. Satellite telemeter at station.
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 1879, 41.5 ft, June 14, 1935, discharge, 380,000 ft³/s, from information by local resident.