Can Dams Make The Guadalupe River Safer?

 Burke 

In the early morning hours of July 4^th, the Texas Hill Nation obtained a document quantity of rainfall: at Hunt, Texas, about eight inches fell in 4 hours.

On account of the great deluge, the Guadalupe River rose out of its banks and claimed the lives of 136 folks. The main focus of nationwide consideration has been on Camp Mystic, the place 27 kids and workers perished. Is there an engineering resolution to reduce the lack of life from floods on the Guadalupe River? As an engineer who has labored on many heavy building initiatives, that is how I see the problems. 

The U.S. Geological Survey has a measuring station at Hunt, so we all know the standard river stream all year long: about 10 to twenty cubic toes per second (cfs) at this station. At 10 p.m. on July 2, the stream was 6 cfs, however solely two days later the stream was a whopping 120,000 CFS. This positively mind-boggling stream prompted the disastrous flooding on the Guadalupe River, when on July 4^th the river rose 26 ft. in 45 minutes!

There have been main flash floods within the Texas Hill Nation in 1987, 1991, 1997, 1998, and 2002. Heavy rain, rocky soil, and steep terrain mix to create devastating flash floods. 

The South Fork of the Guadalupe, alongside which Camp Mystic is positioned, begins within the southwestern a part of Kerr County and flows northeast for 27 miles till it meets the North Fork at Hunt, Texas. At this level, the mixed forks develop into the “Guadalupe River.” The North Fork of the Guadalupe River rises within the western a part of Kerr County. It flows east for 29 miles till it merges with the South Fork at Hunt, Texas. The Guadalupe River flows for about 250 miles to the Gulf of America.

There are a number of doable engineering choices.

Like all rivers, the riverbed can carry solely a lot water. To reduce floods, engineers typically enlarge the riverbed to permit the riverbed to hold extra water downstream. River channelization typically contains eradicating bushes and shrubs which partially block the stream of water, and this work has already been carried out by the scouring motion of the current flood.

One other measure is to widen and deepen the riverbed. That is completed by excavating or dredging the riverbed. As soon as once more, the floods have scoured many of the free materials away, however there would possibly stay locations the place the riverbed needs to be widened or dredged. 

Though they might compromise the looks of the river, I consider floodwalls may assist, too. These needs to be constructed chosen places alongside the North and South Forks, of strengthened concrete about 2 ft. excessive. A floodwall that’s any greater would make it pretty tough for campers to get to the river.

The Guadalupe River system has quite a lot of dams, however they’re downstream from Hunt, Texas. Many of those dams under Kerrville, Texas have been constructed within the 1920’s and 1930’s, and they’re in unhealthy situation. Some have been repaired.  

There aren’t any main dams on the South Fork or the North Fork of the Guadalupe River, however there are a variety of low dams designed to type small lakes.

How Dams Would Defend Lives

The realm that wants bigger dams is that this South Fork/North Fork within the Texas Hill Nation. The dams would offer probably the most safety, permitting floodwater to be saved safely in reservoirs after a excessive rainfall occasion and launched at acceptable instances.

I suggest learning the potential for 2 dams, close to the headwaters of every fork, each 60-ft excessive of roller-compacted concrete with a crest elevation of two,100 ft above imply sea stage. Each dams ought to embrace floodgates and concrete-lined spillways with tainter gates. By damming the river at these places, sufficient water can be captured from a number of tributaries to cut back downstream flooding. 

Civil Engineers ought to search for further doable damsite places alongside the South Fork and North Fork. Cypress Creek empties into the South Fork at Camp Mystic, and an extra dam needs to be constructed upstream on this creek. 

There are numerous environmental and monetary causes for permitting the Guadalupe River to stay as it’s, however human lives can’t be changed. Engineering options would permit campers to remain near the river with a lot much less threat.

Henry Burke, who was a registered skilled engineer for a few years, is retired from Kiewit Corp. He could be reached at hwburke25@gmail.com.