Texas Has Thousands of Bad Dams, Two In Houston Deemed ‘Extremely High Risk’

As Houston Public Media reported in March of 2016, millions of dollars are being spent to repair two dams that hold back storm water on the west side of Houston.

They are among over 7,000 dams listed as “hazardous” in Texas. But because so many people and structures would be at risk should these two dams fail, they’re getting attention.
Here’s the deal with what could be a terrible threat to Houston: most of the time, it isn’t. In fact, it’s a 26,000 acre recreational greenspace on Houston’s west side. It lies on both sides of the Katy Freeway at Highway 6.

On one side is the Addicks Reservoir. On the other is the Barker Reservoir. Both have dams, but most of the time there is very little water to be held back by either. So the acreage is used for parks and has miles of paved bike trails.

Even a moderate rainstorm created a pool of water but only right up behind the Barker Reservoir dam.

“When you need Addicks and Barker is when it’s been raining for a couple of weeks,” Blackburn said. “That’s what we’re worried about, these big storms that follow each other. Where you get two or three or four storms within a couple of weeks period. That’s the scary thing.”

Scary because with successive storms, the reservoirs wouldn’t have time to drain and water would get higher and higher. In the history of the two dams, the reservoirs have never been more than a third full but what if they filled beyond that and the dams failed?

Richard Long, the dams’ manager, offers this scenario: “Because of our flat terrain here, we don’t have a valley that the flood would go down. It’ll spread out over a very large area. It won’t be like the horror movies you see where a wall of water is coming down a canyon. It would be very rapidly rising water and cause an extremely large amount of damage and possibly a loss of life.”

The Army Corps estimates that a dam failure could cause flooding from Buffalo Bayou and Downtown all the way over to Brays Bayou and the Medical Center. For years, the Army Corp has been monitoring “seepage” of water underneath the dam gates. Those leaks led to the Corps designating the Addicks and Barker dams “extremely high risk” and among the six most critically in need of repair in the nation.

In 2016 the Army Corps has committed $75 million to completely replace the big gates on both Addicks and Barker dams. Work is just now beginning and will take up to four years to complete.

Voluntary evacuations have been issued for people living near the Addicks and Barker reservoirs as officials have already started the controlled release of water into Buffalo Bayou early Monday morning.

The controlled release from the Barker Reservoir will take place about 24 hours later, officials said. The release will cause a rise of 4 to 6 inches per hour in the Buffalo Bayou and will cause more water to flow both upstream and downstream.