The following words and terms, when used in these sections, shall have the following meanings, unless the context clearly indicates otherwise.(1) Lake Austin water quality area--Those portions of the Lake Austin watershed within 10 stream miles of the pool level of Lake Austin (492.8 feet, mean sea level).(2) Lake Austin watershed--Lake Austin and its tributaries located between Tom Miller Dam and Mansfield Dam.(3) Lake Travis water quality area--Those portions of the Lake Travis watershed within 10 stream miles of the pool elevation of Lake Travis (681 feet, mean sea level).(4) Lake Travis watershed--Lake Travis and its tributaries located between Mansfield Dam and Max Starcke Dam, but only that part of the Pedernales River and its tributaries within 15 stream miles of the pool elevation of Lake Travis.