Here’s what to expect when eight floodgates open on the Mansfield Dam

It’s never happened before, but the Lower Colorado River Authority will likely open eight floodgates on the Mansfield Dam above Lake Austin by noon Thursday.

So, what can you expect if you live in Austin?

---

Flooding On Some Streets

---

When eight gates are open, 50,000 cubic feet of water per second will flow from the dam.

That will cause some streets to flood, says Karl McArthur with Austin’s Watershed Protection Department.

“We would definitely have to close Cesar Chavez in the vicinity of Lamar Crossing,” he said. “At Longhorn Dam we would have flow over the emergency spillway. The emergency spillway is Pleasant Valley Road, so we’d have to close Pleasant Valley Road there.”

(You’ll able to find a list of road closures at ATXfloods.)

---

Flooding In Some Parks

---

Expect serious flooding on parks along the lake, McArthur said.

With eight floodgates open, he says, you can expect to see something like that photo of the statue of Stevie Ray Vaughan at Auditorium Shores with water up to his waist. That’s why the hike and bike trail is closed.

---

Minimal Structural Damage, Probably

---

One thing McArthur doesn’t expect the opening all gates to cause is flooding of many structures along the river. Of course, that could change if weather forecasts do.

This story was produced as part of the Austin Monitor’s reporting partnership with KUT. Photos by Jorge Sanhueza-Lyon/KUT.

The Austin Monitor’s work is made possible by donations from the community. Though our reporting covers donors from time to time, we are careful to keep business and editorial efforts separate while maintaining transparency. A complete list of donors is available here, and our code of ethics is explained here.