Lake Houston Gates Project Moves Closer to Reality

The Lake Houston Gates Project is moving closer to reality with breakthroughs on the benefit/cost ratio, funding and endorsements.

City of Houston Mayor Pro Tem Dave Martin and Chief Recovery Officer Stephen Costello provided updates today at City Hall on the Lake Houston Gates Project. The wide-ranging, hour-long discussion covered several related topics. They included a critical path for the gates, dredging of the lake, funding for both, several related engineering studies, a favorable ruling from FEMA on the Benefit-Cost Ratio, and an endorsement of more gates by the Greater Houston Partnership to the area’s legislative delegation.

Need For Gates

For those new to the area, the City of Houston has been pushing to add additional gates to the Lake Houston Dam ever since Harvey in 2017. Upstream, Lake Conroe’s gates can release 150,000 cubic feet per second (CFS). But Lake Houston’s can only release 10,000 CFS.

The disparity in discharge capacity complicates joint-reservoir-management and pre-release strategies designed to avoid flooding by reducing the water level in Lake Houston.

Lake Houston releases cannot keep up with Lake Conroe’s. And pre-releasing water from Lake Houston takes so long that storms can veer away during the lowering process, often resulting in wasted water – an important consideration for a water-supply lake.

According to Martin and Costello, benefits of the gate project include:

• Serves as first phase to extend the life of the Dam
• Enables the rapid lowering of lake levels in advance of a flood
• Eliminates the need for a seasonal lowering of both Lake Houston and Lake Conroe
• Provides potential water rights savings
• Protects an estimated 5,000 residential properties in the surrounding area
• Yields an estimated $1/2 billion economic benefit to the life of the project

Gates, Funding, BCR, Studies

Preliminary engineering studies evaluated about a dozen different alternatives for adding discharge capacity to Lake Houston. The City initially favored adding crest gates to the spillway portion of the dam, but discarded that idea after further study as too risky. The engineering company cautioned the City that it would have a difficult time finding contractors willing to risk modifying a 70-year old concrete dam.

So the City then revisited adding various numbers of tainter gates to the eastern, earthen portion of the dam. Because these exceeded FEMA’s funding, the City had initially focused on crest gates. But after investigating the safety issues with those, the City decided to seek more funding for tainter gates instead. The City recommends adding 11.

The picture below is slightly wider and shows both halves of the dam.

Funding Needs

FEMA initially set aside $50 million for the gates. Plus Harris County committed $20 million in the 2018 Flood Bond to attract FEMA’s match. But the latest construction estimates show eleven tainter gates could cost between $200 and $250 million.

After engineering and environmental studies, only $68.3 million in funding remains. That includes an earmark secured by Congressman Dan Crenshaw. So the City is seeking another $150 million from the State of Texas. Martin and Costello have made weekly trips to Austin so far during this session to line up support from legislators, committee chairs, and the Texas Division of Emergency Management.

Social Benefits Improve Benefit/Cost Ratio

All this is suddenly possible because of a favorable ruling from FEMA on the benefit-cost ratio (BCR). Houston Mayor Sylvester Turner and Costello met with FEMA. For years, Houston struggled to get the BCR for the project above 1.0, meaning benefits would exceed costs. Usually, FEMA strictly interprets benefits as “avoided damages” to structures. But FEMA allowed the City to add the value of “social benefits.” Social benefits can include such things as avoiding lost wages and transportation disruptions; reducing negative impacts on student achievement, and more. The social-benefit ruling covers a number of City projects, not just the gates.

Said Costello, “The minute the social benefits came in, everything was great.” Instead of struggling to reach 1.0, the City is now far beyond it.

Greater Houston Partnership Endorsement

With that out of the way, the Greater Houston Partnership wrote a powerful letter to state legislators seeking their support for the gate project. See below.

The Partnership includes business leaders from 900 member companies in the 12-county Houston Region.

Dredging Update

While pressing ahead with the gates project, the City is also working on a long-term dredging plan for the lake and working with the SJRA on sedimentation and sand-trap pilot projects.

The Texas Water Department Board (TWDB) has estimated sediment inflow to Lake Houston at about 380 acre-feet of material annually.

The lake has already lost more than 20,000 acre feet of capacity due to sedimentation. That worsens flooding. While the Federal Government supports efforts to improve Lake Houston now, the chances of getting more money in the future will be reduced – unless we can show that we’re at least keeping pace with annual sediment deposits.

Since Harvey, FEMA, the Army Corps, TWDB, and City of Houston have removed almost 4 million cubic of material from the lake at a cost of $226 million.

We have to prevent more sediment from coming downstream or dredge it after it gets here.

Stephen Costello, City of Houston Chief Recovery Officer

The City is currently lobbying for another $50 million for maintenance dredging to add to the money secured in the last legislative session by now-retired State Representative Dan Huberty. New Representative Charles Cunningham will reportedly now carry that banner forward along with State Senator Brandon Creighton.

Legislative News to Follow

March 10th is the last day to file bills in the Texas Legislature this year. Please visit the legislation page on ReduceFlooding.com for updates once bills are filed and start moving forward in Austin.

Thanks to all of our elected and appointed representatives who have pushed so hard on so many fronts for the last 2008 days to tie all the pieces of this complicated flood-mitigation puzzle together.

Posted by Bob Rehak on 2/27/2023

2008 Days since Hurricane Harvey

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