San Marcos River Origin Traced to Earthquake
By Greg Fieg
In prehistoric times the clear, cool, pristine water flowed through vast uncharted channels, chambers, caverns and underground conduits deep within the porous stone of the Texas Hill Country. Then suddenly the earth rumbled, shook and roared in what must have been as great an earthquake as modernity has ever witnessed, and a magnificent subterranean stream emerged as if from behind a huge, secret door.
Today the San Marcos River continues to originate from that spot where the Balcones Fault ruptured millions of years ago and in one bold, swift move provided the valley with 85 miles of life's most critical sustenance.
The Texas salamander, unique to the San Marcos River in all the world, offers living proof of the river's constancy over the eons, for if the river had been interrupted in even the most severe drought, these creatures and others would not have survived.
The source of the river is located on the campus of Texas State University in San Marcos, a historic and charming city of more than 35,000 inhabitants on the Interstate Highway 35 corridor between Austin and San Antonio.
Though the river flows more than 80 miles southwest to join the Guadalupe River before emptying in the Gulf of Mexico 260 miles away, only about 16 miles show the unmistakably pristine water that makes conditions ideal for such recreation as swimming and tubing. There water temperatures are constant at about 72 degrees, allowing bathers to immerse themselves virtually year around.
Farther downstream, canoeing and kayaking are popular, but mostly among the more intrepid because the San Marcos' banks are frequently interrupted by sharp rocks, rapids, low bridges, dams, steep banks, heavy foliage and other impediments, and some recreationists have lost their lives.
The river's source, known as Aquarina Springs, has glass-bottom boat tours and other acitivities, and each year at the second Saturday in June San Marcos becomes host of the Texas Water Safari canoe race.
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