USGS Water-Year Summary 2020
08153500 Pedernales River near Johnson City, TX
LOCATION - Lat 30°17'30", long 98°23'57" referenced to North American Datum of 1927, Blanco County, TX, Hydrologic Unit 12090206, near left downstream end of bridge on U.S. Highway 281, 0.2 mi downstream from Towhead Creek, 1.1 mi northeast of Johnson City, 3.4 mi downstream from Buffalo Creek, and 48.0 mi upstream from mouth.
DRAINAGE AREA - 901 mi².
- WSP 1632: 1953(M), 1957, 1958(M). WDR TX-81-3: Drainage area. WRD TX-03-4.
PERIOD OF RECORD - May 1939 to current year.
PERIOD OF RECORD, Water-Quality.--
CHEMICAL DATA: Apr. 1948 to Sept. 1950, Feb. 1969 to Sept. 1985.
BIOCHEMICAL DATA: Feb. 1969 to Sept. 1973.
BIOLOGICAL DATA: Feb. 1969 to Apr. 1969.
RADIOCHEMICAL DATA: Nov. 1980 to June 1981.
GAGE - Water-stage recorder and concrete control. Datum of gage is 1,096.70 ft above NGVD of 1929. May 4 to Sept. 13, 1939, nonrecording gage, and Sept. 14, 1939, to Sept. 10, 1952, water-stage recorder at upstream side of bridge at same datum. Sept. 11, 1952, to June 29, 1953, nonrecording gage, and June 30, 1953, to Oct. 7, 1954, water-stage recorder at site 360 ft downstream at same datum. 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 - Flood of July 1869, reached a stage of 33 ft from information by local residents.