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Canyon Lake Gorge

Updated: May 19

What does catastrophic flooding today tell us about the truth of the global flood?

Application: Catastrophic events, like the global flood, are responsible for most of the major geological features we observe today.

In this Lesson, Dr. Bob visits Canyon Lake Gorge in the Texas Hill Country. This was the site of a major flood event in 2002 that provides insight into the evidence for the global flood how the retreating flood waters carved the canyons visible in the world today..

Supplemental Information

The 2002 flood was the first time that floodwaters flowed over the Emergency Spillway since this reservoir was completed in 1964. It was expected that it would take five years to fill it, but by 1967 the rains in this area of Central Texas had already filled it. This was a prelude to how massive this watershed's impact would be.

The Guadalupe River basin forms a part of "Flash Flood Alley" which is one of the river basins most prone to flash flooding in the world. Nine people were killed by the flood over a 20 miles stretch of the river, which damaged or destroyed 48,000 homes and cost around $1 billion in damages.

Constructed to provide flood control and water conservation, the Canyon Dam and Reservoir Project was designed to reduce the damage from flooding events that often hit the Lower Guadalupe River Basin. Once such event occurred in the summer of 2002. On July 1, 2002, after three days of rain across the Upper Guadalupe River Basin, Canyon Dam's reservoir waters began to rise. By 4 p.m. on July 1, reservoir levels had risen 5 feet. The rain continued to fall across the Upper Guadalupe River Basin. By July 3, reservoir levels had risen to just 10 feet below the spillway.

The lip of Canyon Dam sits 974 feet above sea level. It is an earthen dam which works well as long as water does not spill over the top, or undermine the base. To prevent this, a 10-foot release tunnel below the dam allows up to a maximum of 5,000 cubic feet per second (cfs) to be released downstream. The Canyon Dam tunnel typically releases a constant 300 to 500 cfs downriver. Ultimately over 67,000 cfs would flow out of the lake.

As further protection to the earthen dam, a spillway was created. It is excavated limestone more than 1,000 feet wide. The spillway route follows the downward slope of a small wooded valley for about a mile and a half before it crosses under an access road. The spillway route continues for another mile beyond this road as a wider drainage before it finally meets the Guadalupe River below the dam. This spillway allows lake water to "spill" out of the reservoir should water levels exceed 943 feet above sea level. This a difference of 31 feet between the spillway and the top of the dam. Prior to July, 2002, this spillway had never been used.

As rains continued to fall, the reservoir level reached 938 feet in the early morning hours of July 4, just 5 feet below the spillway. Homes and businesses were evacuated. By 3:30 p.m. the reservoir water levels exceeded 943 feet and the water began to go over spillway. Water flooded the limestone slab, ran the 2.5-miles down the natural spillway and entered the Guadalupe River below. The rain continued to fall.

Reservoir levels continued to rise, exceeding 950 feet. It is estimated that over 300,000 cubic yards of rock and soil were carried the 2.5 miles down to the spillway to the Guadalupe River. 1-1/2 to 3 times the amount of water stored in the lake (at normal level) went over the Spillway during the flood event.

Water continued to flow over the Spillway for approximately 6 weeks. Rocks, trees, logs, and other flood debris piled up in the Guadalupe River and created a huge blockage. Flooding continued from the dam to the Gulf Coast.

Over the space of three days the rushing water gouged out a canyon 1.5 miles long and up to 80 feet deep. This canyon now sits behind the emergency spillway of Canyon Lake.

Fossils Revealed

The canyon formed by these floodwaters revealed the history of this area. Walking through the canyon is an opportunity to walk through the events of the global flood. There are tracks of carnivorous Acrocanthosaurus, a mini Tyrannosaurus rex around 30 feet long that walked on its hind legs, and a massive sauropod - the Pleurocoelus (the official dinosaur of Texas). The presence of these tracks provides evidence to the rapid burial necessary for their preservation.

A variety of fossils were uncovered by the waters destructive force. There are giant gastropods, algae, clams, snails and tiny shells in rock layers throughout the gorge. In fact, an entire fossil ridge that demarcates the Upper Glen Rose and the Lower Glen Rose can clearly be seen while descending the gorge.

The Hidden Valley Fault is also on display. The fractured, and gouged rocks of multiple layers are exposed to examination. It is the only location where the fault can be viewed directly.

Karst Aquifers

Water still passes through the gorge. It flows into the canyon along fractures in the harder layers and is seeping from the walls where fractured, permeable layers crop out. It is an amazing illustration of a karst aquifer system.

Karst is a special type of landscape that is formed by the dissolution of soluble rocks, including limestone and dolomite. Karst regions contain aquifers that are capable of providing large supplies of water. More than 25 percent of the world’s population either lives on or obtains its water from karst aquifers. In the United States, approximately 20 percent of the land surface is karst and roughly 20 percent of all groundwater withdrawals in the year 2000 came from karst aquifers.

Catastrophic Canyon Formation

The Canyon Lake Gorge is reminiscent of the canyon that was formed at Mount Saint Helen's. The "Little Grand Canyon," about 1/40th the size of Arizona's Grand Canyon, was formed on March 19, 1982, after a dam breach triggered a catastrophic mudflow at Mount St Helens.

There are a variety of locations around the world that demonstrate the massive power of catastrophic floods. All of them pale in comparison to the global flood recorded in Genesis. They do, however, give us reason to trust the accuracy of the Biblical account. The evidence we see in each of these catastrophes reveals the geological evidence, and the current reality of God's Word. A walk through this canyon, and many others, is a walk through history, a history accurately described in the Bible.


Scripture References

  • "And, behold, I, even I, do bring a flood of waters upon the earth, to destroy all flesh, wherein [is] the breath of life, from under heaven; [and] every thing that [is] in the earth shall die." Genesis 6:17

  • “And if it seem evil unto you to serve the LORD, choose you this day whom ye will serve; whether the gods which your fathers served that [were] on the other side of the flood, or the gods of the Amorites, in whose land ye dwell: but as for me and my house, we will serve the LORD.” Joshua 24:15

  • "The LORD sitteth upon the flood; yea, the LORD sitteth King for ever.'" Psalm 29:10

  • "For as in the days that were before the flood they were eating and drinking, marrying and giving in marriage, until the day that Noe entered into the ark, And knew not until the flood came, and took them all away; so shall also the coming of the Son of man be." Matthew 24:38-39

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Dr. Bob visits Mt Saint Helen's.

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