More than one year after Hurricane Harvey hit southeast Texas, the city of Houston is attempting to secure grant funding to add 10 gates to the Lake Houston Dam, which Houston City Council Member Dave Martin said he believes is the most important flood prevention project in the Lake Houston area.
In August the city submitted a grant application for the roughly $50 million project to the Texas Department of Emergency Management, which approved the application and forwarded it to the Federal Emergency Management Agency. If FEMA approves the application an engineering study for the project could begin in the first quarter of 2019, Martin said.
The additional 10 gates would allow the city to release water at a much higher rate prior to heavy rain storms and during flooding events. This could potentially prevent homes and businesses near the lake from flooding, Martin said.
“I think [adding gates to the Lake Houston Dam]is the No. 1 project to maintain long-term stability of our neighborhood,” Martin said. “Not only Kingwood, but Humble and all of the other areas around us. All areas need to be concerned about it.”
When it was built in 1954, Lake Houston’s only purpose was to serve as a reservoir to hold water for residents in the Greater Houston area to use. The dam consists of four gates, two of which are radial gates used for releasing high volumes of water, while the other two are flashboard gates used for minor adjustments to the lake level.
The addition of 10 gates to the lake’s dam would create a second purpose for the lake as it would act as a flood-control mechanism, said Matt Zeve, Harris County Flood Control District chief operations officer.
In addition to the four existing gates on the Lake Houston Dam there is a long spillway that water flows over when the lake floods. When Lake Houston is at its normal elevation of 42.5 feet, the four existing gates on the dam can release water at a rate of 10,000 cubic feet per second, according to a brief report completed by engineering firm Freese and Nichols in February.
“Lake Houston is really designed to overflow … over that very long spillway,” Zeve said. “This potential project is a major modification of the operation and purpose of Lake Houston.”
During Hurricane Harvey, water entered the lake at a rate of 430,000 cubic feet per second, causing the lake to reach an elevation of 53.01 feet, according to the Freese and Nichols study. The lake was not able to release water fast enough, which caused water to back up and contributed to the flooding of thousands of homes and businesses in the Lake Houston area, Zeve said.
Following Harvey, the city of Houston began prereleasing water from Lake Houston to lower the lake by up to 2 feet prior to heavy rain events. Adding gates to the dam would make this prerelease process much quicker, Martin said.
According to the Freese and Nichols study, each potential gate the study looked at could release 3,600 cubic feet of water per second when the lake is at its normal elevation of 42.5 feet.
“[Adding gates] gives us the ability to release water and get it out of our backyard in an instant,” Martin said. “Right now in order to lower the lake 1 foot, it takes us more than 24 hours. With 10 additional gates we could probably release 1 foot of water within one hour.”
Not only is adding gates to the Lake Houston Dam a priority for Martin—whose district includes Kingwood and other parts of the Lake Houston area—it is a priority for the city of Houston, according to city officials.
During a presentation to Houston City Council on Nov. 28, former Houston Chief Recovery Officer Marvin Odum said the project is one of four the city plans to fund using the $257 million the city anticipates it will receive from the Hazard Mitigation Grant Program.
The federal program is funded and administered by FEMA, but the state of Texas determines where and how funding is allocated, said Shontae Davis, group supervisor for the program.
Davis said almost $900 million of Hazard Mitigation Grant funds are available for the state of Texas as a result of Harvey. Local entities first submit applications through the state, and if the state supports the project it will pass the application to FEMA for review. The application for adding gates to the Lake Houston
Dam is under review, and Davis said there is no set timeline on how long the process takes.
FEMA reimburses local entities for 75 percent of the total cost of approved projects, while the local entity pays the remaining 25 percent, Davis said.
Part of the city’s share of the Lake Houston Dam project cost could be funded by the $2.5 billion Harris County Flood Control District bond voters approved in August 2018, Zeve said.
In addition to adding gates to the Lake Houston Dam, officials are working on other flood prevention projects in the Lake Houston area.
The Army Corps of Engineers is dredging a 2-mile stretch of the West Fork of the San Jacinto River to restore the river to pre-Harvey conditions. The work started in September and is scheduled to finish in May 2019.
Additionally the HCFCD began work on a drainage improvement project in Huffman in the fall of 2018 and will begin similar projects in Kingwood and Atascocita in 2019, Zeve said. HCFCD has $10 million of bond funds allocated for each drainage project.