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 on 2/27/23 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 construction
- Dredging of the lake
- Funding for gates and dredging
- Several related engineering studies
- A favorable ruling from FEMA on the Benefit-Cost Ratio
- An endorsement to the area’s legislators by the Greater Houston Partnership.
Need For Gates
For those new to the area, the City of Houston has been pushing to add 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. That’s an important consideration for a water-supply lake.
According to Martin and Costello, the gate project will:
• Serve as the first phase of a long-term effort to extend the life of the Dam
• Enable the rapid lowering of lake levels in advance of a flood
• Eliminate the need for a seasonal lowering of both Lake Houston and Lake Conroe
• Provide potential water-rights savings
• Protect an estimated 5,000 residential properties in the surrounding area
• Yield an estimated half billion dollars in economic benefits during 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.
However, the City discarded that idea as “too risky” after further study. 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. The potential liability was just too great. So the City then revisited adding various numbers of tainter gates to the eastern, earthen portion of the dam.
Because tainter gates exceeded FEMA’s funding, the City had initially focused on crest gates. But after investigating the safety issues, the City decided to seek more funding for tainter gates instead.
The City now recommends adding 11 tainter gates.
The picture below is slightly wider and shows more of how both halves of the dam come together.
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).
For years, Houston had struggled to get the BCR for the gate project above 1.0 (the point at which benefits exceed costs). Usually, FEMA strictly interprets benefits as “avoided damages to structures.”
But Houston Mayor Sylvester Turner and Costello met with FEMA to argue that the problem was much bigger than damaged structures.
As a result, FEMA allowed the City to add the value of “social benefits” to the BCR. Social benefits can include such things as avoiding lost wages when businesses are destroyed; transportation disruptions that reduce the region’s productivity; reducing negative impacts on student achievement when schools are disrupted; and more.
The social-benefit ruling covers a number of City projects, not just the gates. It should also benefit other areas, especially rural ones.
Said Costello, “The minute the social benefits came in, everything was great.” Instead of struggling to reach 1.0, the City is now far above 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.
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 yards of material from the lake at a cost of $226 million.
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