1964 6mw Canyon Lake Dam on Guadalupe River in Canyon Lake, TX

(Satellite)

Street View, Jun 2023

USACE, Fort Worth District

This is the first reservoir on the Guadalupe River that the deluge of the catastrophic July 4, 2025, flash flood first encounters. It was so empty because of a drought that it easily absorbed all of the water. But here is an example of social media sensationalism. Fortunately, several comments called them out on it.

Economic Hell posted 0:46 video
Canyon Lake water level increased by 10 feet as torrential rains flood the Guadalupe River. With just 66 feet left before spillage, residents are urged to evacuate die tobthe floodings. Six dead so far — and more rain is coming. Stay alert, Texas.

Robbin Homan: This is not true.

I own a house on lake Dunlap, Canyon lake was about 30’ below normal. It took in all of the flood water and only rose about 10’. It could handle three times what it got. This is exactly what the lake was built for.

[Another comment indicates that the water level still hasn't reached some of the boat ramps.]

They had to use an old photo to make the lake look nearly full. A comment provided this photo.

Diana Holcomb Coffey commented on the above video

USACE

"The Texas Water Development Board reported that Canyon Lake, as of noon on Monday, was up nearly 11 feet from a week ago and stood at nearly 889 feet or nearly 62% full. Its full conservation pool sits at 909 feet. It was 46% full before the rains over the Fourth of July weekend." [tpr]

I dug deeper to find the flood pool elevation: 943'.

gbra

 The dam is 224 feet high and 6,830 feet long.

At Conservation Pool elevation of 909 feet mean sea level (msl), the Reservoir covers approximately 8,200 surface acres and impounds 378,852 acre-feet of water to a depth of 140 feet.

At maximum Flood Control Pool elevation of 943 feet msl, the Reservoir impounds a total of 732,600 acre-feet of water.

The Emergency Spillway is at 943 msl.

Even if the lake had been at conservation pool (the desired level), it would have handled the flood waters. The water can rise 34' above the conservation pool before it would go over the spillway. And the 10' rise would have been less at the higher level because the lake rises slower as the lake goes up because it spreads out over more land. When the lake reaches the conservation pool, the USACE releases 12kcfs until the level is back down to the conservation pool.

gbra
The 6mw powerhouse began generating electricity in 1989.
The lowest level of the reservoir was 877.49' on May 13, 2025, and the spillway has been topped only once, in 2002.

It will be a while yet before the lake can be used for recreation because it is now full of debris. And is is still well below conservation pool.

My Lake News posted 0:23 video on July 5 at 2:51