Lake Houston Gates Update - Reduce Flooding

9/23/26 – Houston City Council Member Fred Flickinger’s October 2026 town hall meeting featured three speakers on the project to add more floodgates to the Lake Houston dam.

Coastal Water Authority (CWA) Board Member and former State Representative Dan Huberty introduced the topic and two other speakers:

The Need

In his opening remarks, Huberty emphasized the critical need to make sure that installation of new gates didn’t put the existing dam at risk because of the critical role it plays in providing water to millions of people of the region.

Olinger began his portion of the presentation with Hurricane Harvey statistics that demonstrated the scale of the challenge. Harvey became the flood of record for the Houston region.

Olinger said that 2.6 million acre feet of water flowed over the dam during Harvey. That translates to 847 billion gallons…enough water to refill the lake 19 times. And enough to supply all 7.7 million people in the entire Houston region for 5.5 years.

At the peak, 491,000 cubic feet per second (CFS) flowed over the dam. That’s enough, he said, “to fill an empty Lake Houston 19 times.”

He also said that, at the peak rate, the empty lake could refill in 3.3 hours.

The highest water surface elevation during the flood was 53.1 feet…more than. 10 feet above the normal pool level.

The Plan

Next, Olinger described the current release capacity of Lake Houston and plans to increase it. To the east (right) of the 3,100 foot long Ambursen spillway are four small gates that can help lower the lake level.

Those gates can currently release water at about 10,000 cubic feet per second. That’s one fifteenth the release rate of Lake Conroe.

So, Black & Veatch is examining ways to increase that rate. Originally, the plan was to modify the spillway. But that was too risky because of the 75-year-old concrete. So now, the plan is to modify the earthen, eastern portion of the dam at the location shown below (yellow box) approximately 500 feet east of the spillway.

Proposed New Gates

Mueller began his portion of the presentation by talking about objectives and design constraints.

Engineers had to reduce upstream flood risk without increasing downstream risk.

He said, “That got us to what is an 11-gate structure that has the ability to release – in a controlled manner – about up to 84,000 cubic feet per second from Lake Houston. That is roughly eight times the current capability of the existing gates.”

Mueller also described an “approach channel” on the reservoir side that allows water to fill in behind the new gates and a “discharge channel” on the downstream side that will dissipate energy during the release.

Eighty-four thousand cubic feet per second exceeds the release rate from Lake Conroe during Harvey, which was 79,000 cubic feet per second. The gates can be used to lower the lake in advance of or during storms to offset inflows from the East and West Forks.

The recommended structure consists of reinforced concrete piers with 11 steel gates mounted on radial arms. It also contains a bridge on top of the structure for operations and maintenance.

Flood-Risk Reduction Benefits of New Gates

Mueller said the design should reduce the height of flooding by 1.8 feet during both a 100-year storm and a repeat of Harvey. And that should be enough to reduce the number of structures flooded by +/- 20% in each scenario.

Secondary Benefit of New Gates

The existing Lake Houston dam dates back to the early 1950s. Mueller said that the new gates will also provide flexibility to the CWA and City when it comes to future repairs of the dam.

“It’s in need of more or less constant repair and or rehabilitation,” said Mueller. “The gate project gives Coastal Water Authority the ability to divert flows around … work on the concrete structure.”

Mueller added that the gates will also help divert water around work when CWA eventually replaces the dam.

Cost of Project and Funding Gap

Black & Veatch now estimates the cost of construction at $315 million. That’s $41 million more than the estimate from January 2026 ($274 million).

To date, $120 million in funding has been committed. Of that, $80 million comes from the State legislature. Plus, the City and Harris County Flood Control have each pledged $20 million.

That leaves a funding gap of $195 million. Where will the additional money come from? According to Olinger, the current proposed plan may or may not qualify for FEMA aid. The uncertainty has to do with the benefit/cost ratio that FEMA demands and whether the project benefits can meet FEMA’s threshold.

Olinger said that CWA is working closely with the City’s Government Relations Group and Representative Cunningham to fill the gap.

Current Projected Timeline

In addition to the cost growing over time with changes in project scope, the timeline has slipped. Assuming funding can be found, and the Army Corps grants a permit, construction could start in 2028 and finish in 2030, four years from now.

Can It Be Done?

Huberty, a former state legislator, closed the presentation on an optimistic note. He said, “We’ve got the smartest people on the project. I’ve got the support of the Mayor, support of the City Council. Support of our legislative body. And certainly in conversations that we’ve had with the Governor’s office, Lieutenant Governor’s office, and Speaker’s office.”

He continued, “They’re well aware of where we’re at in our planning. They’re well aware of where we are at in our requirements. We have had multiple conversations. We just need to execute upon this strategy.”

In explaining why the project has taken so long, he said, “You can’t ask for what you don’t know you need. Now we know where we’re at. And we’re very bullish as we go forward in executing on the project.”

Huberty also implied that NOT using FEMA funds might get the project done faster.

The next legislative session will definitely be important for the Lake Houston Area.

Click here to download a high-resolution PDF of the entire presentation.

Posted by Bob Rehak on 9/23/26

3312 Days since Hurricane Harvey