USGS Water-Year Summary 2018
08158827 Onion Creek at Twin Creeks Road near Manchaca, TX
LOCATION - Lat 30°07'34", long 97°49'15" referenced to North American Datum of 1927, Travis County, TX, Hydrologic Unit 12090205, on upstream left side of bridge over Onion Creek at intersection of Twin Creeks Road and Arroyo Doble Road, approximately 3 miles south-southeast of Manchaca.
DRAINAGE AREA - 181 mi².
PERIOD OF RECORD - Apr. 2003 to Jan. 2004, June 2004 to current year.
PERIOD OF RECORD, Water-Quality.--
CHEMICAL DATA: Oct. 2004 to May 2005.
BIOCHEMICAL DATA: Oct. 2004 to May 2005.
PESTICIDE DATA: Oct. 2004 to May 2005.
SEDIMENT DATA: Oct. 2004.
GAGE - Water-stage recorder. Datum of gage is 587.8 ft above NGVD of 1929 (from topographic map). Satellite telemeter at station.