According to Houston Mayor Pro Tem Dave Martin, the roughly $200 million new design would entail 11 gates being built into the existing embankment on the east side of the Lake Houston Spillway Dam.
“Building the new gate structure in the east embankment removes the high-construction risk of modifying the existing gate structure, allows continued use of the existing gate structure during construction and eliminates the need for a cofferdam in the lake,” Martin said in a statement.
As of Feb. 3, officials said the city is still awaiting approval from the Federal Emergency Management Agency for the new design.
Officials said the city has been working to add gates to the Lake Houston dam since Hurricane Harvey hit in August 2017, noting the dam was overwhelmed with water being discharged at a rate of 425,000 cubic feet per second. The dam’s current structure can release water at a rate of 10,000 cubic feet per second.
In January 2022, Houston officials said a previous design for the dam improvement project that would have added 1,000 feet of modern floodgates to the existing structure was put on hold because the projected cost significantly exceeded the approximately $48 million FEMA grant awarded for the project.
Officials noted the previous design was given a benefit-to-cost ratio of 0.48, well below the range of 0.75-1 needed to justify the project. The current design, however, received a benefit-to-cost ratio of 2.88, officials said.
While the current design’s cost of roughly $200 million also exceeds the funds allocated in the FEMA grant, Martin said city officials are working with state and federal legislators to secure the additional funding needed to move forward. He noted his office was committed to ensuring the cost of the Lake Houston Spillway Dam Improvement Project is fully funded before he leaves office in December.
“The city of Houston [is] feeling very comfortable with this new [design], working with federal, state and local partners toward finalizing this integral project to fortify the Lake Houston area,” Martin said in a statement.