Having a brand new canyon is sort of a once in a lifetime experience. It might even be more rare than that.
Texas’s Canyon Lake Gorge opened to the public last week — a gorge, a canyon, that was carved out over a couple of days in 2002 when flood waters charging over an overtaxed dam cut through soft soils and soft rock to expose millions of years of sediments. Dinosaur footprints were exposed by the flood, too.
A torrent of water from an overflowing lake sliced open the earth in 2002, exposing rock formations, fossils and even dinosaur footprints in just three days. Since then, the canyon has been accessible only to researchers to protect it from vandals, but on Saturday it opens to its first public tour.
“It exposed these rocks so quickly and it dug so deeply, there wasn’t a blade of grass or a layer of algae,” said Bill Ward, a retired geology professor from the University of New Orleans who started cataloging the gorge almost immediately after the flood.
The mile-and-a-half-long gorge, up to 80 feet deep, was dug out from what had been a nondescript valley covered in mesquite and oak trees. It sits behind a spillway built as a safety valve for Canyon Lake, a popular recreation spot in the Texas Hill Country between San Antonio and Austin.
The reservoir was built in the 1960s to prevent flash flooding along the Guadalupe River and to assure the water supply for central Texas. The spillway had never been overrun until July 4, 2002, when 70,000 cubic feet of water gushed downhill toward the Guadalupe River for three days, scraping off vegetation and topsoil and leaving only limestone walls.
Canyon Lake is southwest of Austin, almost due west from San Marcos about 20 miles. The lake backed up from a 1960 flood control project dam built by the U.S. Army Corps of Engineers — the new Canyon Lake Gorge is managed jointly by the Corps and the Guadalupe-Blanco River Authority.
Watch carefully, dear reader: Creationists will soon start to claim that the rapid cutting of this canyon verifies a young age for all canyons, and shows that the Earth’s geology can indeed be very young. But that claim will gloss over the fact that while the gorge was cut quickly, it was cut through sediments that took millions or billions of years to lay down. The Associated Press reports problems with such a hypothesis:
The sudden exposure of such canyons is rare but not unprecedented. Flooding in Iowa in 1993 opened a limestone gorge behind a spillway at Corvalville Lake north of Iowa City, but that chasm, Devonian Fossil Gorge, is narrower and shallower than Canyon Lake Gorge.
Neither compares to the world’s most famous canyon. It took water around 5 million to 6 million years to carve the Grand Canyon, which plunges 6,000 feet at its deepest point and stretches 15 miles at its widest.
The more modest Canyon Lake Gorge still displays a fault line and rock formations carved by water that seeped down and bubbled up for millions of years before the flooding.
Some of the canyon’s rocks are punched with holes like Swiss cheese, and the fossils of worms and other ancient wildlife are everywhere. The rocks, typical of the limestone buried throughout central Texas, date back “111 million years, plus or minus a few hundred thousand years,” Ward said.
Six three-toed dinosaur footprints offer evidence of a two-legged carnivore strolling along the water. The footprints were temporarily covered with sand to protect them as workers reinforced the spillway, but they’ll be uncovered again eventually, Rhoad said.
Tours for the new gorge are booked for the next six months. Details on how to reserve space can be found at the website of the Gorge Preservation Society (GPS).