What can Kingwood and Lake Houston residents expect to get for a $48 million investment in Lake Houston’s aging concrete dam?
That is the question Black and Veatch engineers are pondering as they reexamine a proposal to update the concrete structure which was built in 1953.
“Our project engineering design team, Black and Veatch, is currently looking at various options to ensure the Lake Houston Dam Spillway Improvement Project stays within budget,” Houston Mayor Pro Tem Dave Martin told The Tribune.
“As some people know,” Martin said, “There were various designs presented that were well over budget. The current design we are pursuing is within our project budget, just shy of $50 million. Concurrently, as these design options will affect the benefit/cost ratio, it’s hard to speculate until design is complete.”
The proposal was to replace the Lake Houston Dam’s four small gates, which can release 10,000 cubic feet of water per second, with a “system of 10 new ‘crest gates’ that would allow the release of four feet of water total from Lake Houston within 24 hours, four times the release rate from the four current gates…,” according to Tribune Correspondent Bruce Olson’s July 19 report on the Lake Houston Spillway expansion.
“With the ability of the new gates, we will be able to release four feet of water in 24 hours, so that gives us the ability to react to a storm like Hurricane Harvey,” Olson reported Martin telling more than 300 Kingwood and Lake Houston residents attending the Town Hall at the Kingwood Community Center July 8.
Four months later, the preliminary design estimates are in and Black and Veatch has determined that the cost of improvements will go “way beyond” the $48 million that the Federal Emergency Management Agency (FEMA) has agreed to fund.
FEMA would fund 75 percent of the $48 million while the remaining 25 percent would be funded equally by the City of Houston and the Harris County Flood District.
Almost a trillion gallons of water fell across Harris County during Hurricane Harvey in 2017. Lake Houston’s storage capacity is 42.4 feet. During Harvey, as the rain continued to fall and water was released from Lake Conroe, the Harris County Flood Control District reported that record pool elevation of 53.1 feet was recorded and, at the peak of the storm, a wall of water 11 feet high was flowing over the Lake Houston spillway and into the homes and businesses of Kingwood.
The purpose of the extra gates was to lower the lake level prior to a flood and to allow for a substantial amount of lake water to be released during a storm.
So, what happens next?
Fewer gates would reduce construction cost, but would it also reduce the advantage? That is what Black and Veatch engineers are reexamining as they review the spillway proposal to see if the dam structure can be modified and how a modified structure would operate during a Harvey or Imelda-type event.
“Once the design is complete, the City of Houston will have a better analysis to determine the overall projected cost of our project, as well as if there has been any reduction in benefits of the project,” Martin said in his statement to The Tribune. “We will not know our benefit cost ratio until the design phase has concluded and Tetra Tech completes the benefit cost analysis, which will be September 2022.”
Lake Houston is owned by the City of Houston to help providing drinking water for city residents and was completed in 1953. It is constructed of reinforced concrete requiring substantial support for the dam to handle the new gates and still maintain its structural integrity, as Black and Veatch engineers scrutinize what Lake Houston can get for its $48 million investment.
Once a preliminary plan is approved and construction begins, the dam will take 18 to 24 months to complete.
“I am committed to delivering a project that is within budget and provides protection from future flooding to as many Lake Houston residents as possible,” Martin said to The Tribune.
Updates about the Lake Houston Dam Spillway Improvement Project and other projects pertinent to Council District E and the Lake Houston area are available on Martin’s webpage, houstontx.gov/council/e/.