Japanese flood tunnel
The devastating flooding in Houston caused by Hurricane Harvey in 2017 killed dozens of people, inundated hundreds of thousands of homes and left the community desperate for a solution.
Since then, local flood experts have extensively studied the possibility of a multibillion-dollar tunnel system across Harris County, where Houston is located. Studies have focused on the construction of pipelines, 30 to 40 feet in diameter, that could ferry massive amounts of water out to the Gulf in the event of a storm.
Now, after years of research and discussion, Elon Musk wants a piece of the project.
An investigation by The Texas Newsroom and the Houston Chronicle has found that the billionaire, in partnership with Houston-area Rep. Wesley Hunt, has spent months aggressively pushing state and local officials to hire Musk’s Boring Co. to build two narrower, 12-foot tunnels around one major watershed. That could be a potentially cheaper, but, at least one expert said, less effective solution to the region’s historic flooding woes.
Hunt’s team has said the Boring project would cost $760 million and involve the company getting 15% of the cost up front from state and local coffers.
Within two months of this push, the Harris County Commissioners Court unanimously voted to study a pilot program that included a look at smaller tunnels, with specifications similar to what Boring had pitched. The commissioners court, made up of five elected members including a county judge, oversees the county’s budget.
Both Musk and Hunt stand to benefit should Boring be selected to build any part of the project. Hunt is reportedly considering a challenge to U.S. Sen. John Cornyn in next year’s Republican Senate primary. And landing a job like this would also be a significant win for Boring, which has not completed a major public project in Texas and faces criticisms for its ventures elsewhere.
The discussions about the Boring pitch have happened mostly out of the public eye. Hunt mentioned the project in passing at a town hall in Houston in February. Since then, he has refused to answer the newsrooms’ questions about when Musk sold him on the idea and why he became its pitchman.
Efforts to reach Musk and representatives with Boring were not returned.
Experts and some local officials question whether Musk and his company are the right pick for the job. The Boring Co. has focused on transportation tunnels, not flood mitigation.
“If you build a smaller tunnel, OK, it’ll be cheaper, but it can carry less water,” said Larry Dunbar, a veteran water resources engineer who has advised Houston-area governmental agencies on drainage issues. “So what have you saved? Have you reduced the flooding upstream by an inch? And are you going to spend multimillions of dollars to do that? Well, maybe that’s not worth it.”
In response to the newsrooms’ questions, state and local officials said no public money has been allocated to Boring. County officials added that they have not chosen a tunnel contractor and any process to do so would follow normal procurement rules.
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As they pushed the idea to state lawmakers, Hunt’s team repeatedly lobbied Harris County officials, reaching out to at least two commissioners, the county’s legislative liaison and flood control experts.
Early on, Houston officials had concerns about what Boring proposed.
The two-page letter from Boring said its tunnels would be “no shallower than 15 feet to 30 feet below ground surface,” while the county’s previous research proposed a much deeper range for the Buffalo Bayou segment.
An engineering expert in County Commissioner Tom Ramsey’s office warned that Boring’s shallower plan could interfere with bridge foundations, utility lines and existing easements.
“It discusses that the tunnel would be much shallower then anticipated,” Eric Heppen, Ramsey’s director of engineering, wrote in an email to other staffers in his office on Feb. 17. “I would quickly confirm if it can be deeper or if that becomes a load challenge for the system.”
Boring said in its pitch that the tunnel depth is “flexible,” but the company did not respond to the newsrooms’ question about whether it can build to the standards outlined in the county’s study.
Volume was another concern. A single 40-foot-wide tunnel can move about 12,000 cubic feet of water every second, county studies show. Two 12-foot-wide tunnels, laid side by side, as Boring proposed, might struggle to keep pace in a flood emergency, according to Dunbar, the veteran water resources engineer.
“One would need eleven 12-foot diameter tunnels to provide the same flow capacity as one 40-foot diameter tunnel,” he told the newsrooms. “Providing only two 12-foot diameter tunnels does not provide the flow capacity that Harris County or the Corps of Engineers are seeking.”
A diagram of tunnels underground. Two tunnels labeled “Boring Co. Plan” are 12 feet wide and 30 feet deep. They look relatively small and shallow compared to another tunnel, labeled “Flood Control District Study,” that is 40 feet across and 140 feet deep.
The county continued to engage with the company despite these concerns.
See here for previous flood tunnel blogging, which I first noted in 2018, as it was then part of the medley of flood mitigation ideas being put forth after Hurricane Harvey. As this story notes, there was a bill passed last year with a push from Reps. Lizzie Fletcher and Wesley Hunt to get the U.S. Army Corps of Engineers to complete an ongoing study on the efficacy of flood tunnels. This is the first reporting on anything like this in Harris County.
So far it seems like a lot of talk, with no money being committed to anything. I generally align with a quote from Jim Blackburn at the end of the story, where he says that the scope of the flooding issue requires all of us to be “open-minded about ideas”, as long as we’re not rushing into any particular project. I also greatly sympathize with Commissioner Rodney Ellis, who says that we should prefer to keep Elon Musk out of it because of his “blatant disregard for democratic institutions and environmental protections”. At the very least, let’s be fully transparent about what’s going on here.
One more thing, on the subject of the tunnels’ sizes. Commissioner Ramsey’s director of engineering is absolutely right about the math. Given that the length of the tunnels would be the same, the volume of a 12-foot diameter tunnel (36π times the length) would indeed be about one-eleventh the volume of a 40-foot diameter tunnel (400π times the length), and so it is reasonable to ask whether it would be worth it to spend the money to build those smaller tunnels, even if it is a lot cheaper. Let’s be sure we know how much volume we need to make this worthwhile, and then we can determine the best and most cost-effective way of getting there.