Ike Dike’s final plan won’t protect against every storm

Bill Merrell knew something had to be done to protect the Texas coast from the moment he looked out of a building on Galveston Island and saw the raging waters below. It was September 2008, and Hurricane Ike had pushed a storm surge up to 20 feet over the nearby Bolivar Peninsula. His strength wiped out communities, with bodies found in the debris.

“The Dutch couldn’t have put up with that,” Merrell told his wife.

Thirteen years later, the Houston area still rests on the 17-foot-high Galveston Seawall that was first built after the catastrophic 1900 hurricane and the dunes that are continually damaged. The Texas City Seawall defends against surges in Galveston Bay.

Merrell’s initial imagination of the so-called Ike-Dike, inspired by the barriers in the Netherlands, evolved into a massive multibillion-dollar plan. A final version of what is now the Army Corps of Engineers Coastal Texas Study is expected to be released on September 10 and then sent to Congress for approval and funding.

Still, that may not be enough – and it certainly isn’t a panacea, especially as climate change is making the region’s luck worse, leading to rising seas and hurricanes that are expected to be stronger.

The more than $ 23 billion Galveston barrier system portion of the project will not protect against the strongest hurricanes. (And the cost estimate in the final report is expected to increase.) But the price for additional protection could be higher than what politicians and taxpayers want to pay.

“You can assure people that you are never going to flood,” said Chris Sallese, who served as district commander for the Corps in Galveston between 2010 and 2013, “but is that what you’re ready to to pay?”

The Army Corps uses a cost-benefit analysis, among other factors, to decide what to design. The centerpiece of the plan is an ambitious gate system that would stretch from the eastern end of Galveston Island at the mouth of the bay to the Bolivar Peninsula. It is intended to prevent a storm surge of up to 22 feet from entering the bay and up the industry-lined Houston Ship Channel.

The agency argues that building to this height is the best use of money, even when sea levels rise, earning $ 2 for every $ 1 spent and paying for itself after a storm. This assumes moderate sea elevation. Merrell, professor of marine science at Texas A&M University in Galveston, hopes it will be designed in such a way that it can be strengthened if conditions change or new technologies develop.

Even then, the wrong combination of events could still overcome it.

“There could be bigger storms hitting it, and you would have what they call an overflow, basically a bay spill,” said Kelly Burks-Copes, Corps project manager. “But we have to assess and trade the return on investment to build bigger and bigger.”

The design and construction of the proposed valves is expected to take up to 20 years. It remains to be seen how useful they will be then – or over the course of half a century or more that the structure should work then. It is impossible to predict the sea level rise exactly. The Dutch barriers are built at a much higher level.

The Coastal Texas study may not even meet the protection level for every 100-year storm, or storms with a 1% chance of occurring in a year, Merrell said.

“Obviously places like Houston with all the refineries and everything should be protected from a bigger storm; everyone will admit it, ”said Merrell, 78. “One of the peculiarities of this particular Corps project is that it hasn’t even reached 100 years of protection, which is sad. It’s not so much protection.

The proposal illustrates the balance that Houston leaders must be between what we are willing to pay and what we are willing to risk. Planners argue that the barrier will still reduce damage and reduce the number of people at risk, even if a stronger storm hits.

The draft plan put the price of the Galveston barrier system at $ 23.5 billion, of which the federal government would fund 65 percent. (A few billion more was earmarked for environmental restoration.) The remainder would go to a tax district created by the Texas legislature, the Gulf Coast Community Protection and Recovery District. A board of directors builds the agency from scratch to raise funds and make the system work. He can also propose an alternative plan but will have to cover additional costs for this one.

The Galveston Bay Storm Barrier System

Houston Chronicle

Heading the board is Michel Bechtel, Mayor of Morgan’s Point, which sits at the start of where the shipping channel winds past the communities. Bechtel believes that the surge can “of course” be mitigated, although the deep channel should act like a straw and attract the surge. He thinks the draft proposal was too weak.

“The board will have to think about it very seriously and basically say: is this strong enough? Bechtel said. “Is this the best we can do?” “

Critics fear that although the gates will be 22 feet high, the second tallest dune line on Galveston Island and the Bolivar Peninsula will rise only 14 feet. Clint Dawson, chairman of the Department of Aerospace Mechanics and Engineering at the University of Texas, modeled a Category 5 storm uniformly hitting a barrier at this lower height and always saw significant flooding.

Properties at risk of flooding include industrial sites with those familiar round chemical storage tanks. Power surges can also send debris there, damage it, or dislodge it and push it elsewhere.

Blake Eskew, a former consultant in the oil and gas industry, has counted 2,900 hazardous reservoirs with a capacity of over 4 billion gallons of product.

Dawson’s modeling was used by a team at Rice University’s Severe Storm Prediction, Education and Evacuation from Disasters Center, who are working on a proposal that could provide additional protections sooner. The corps plan includes surge protection measures in the bay; Rice’s plan calls for a system of barriers extending down the middle of the bay towards the ship channel. (He’s still trying to get funding from the City of Houston and Harris County for further study.)

With the Coastal Texas plan, there remain concerns, from a granular perspective to the big picture, about damage to fish and oysters, beach access, and vulnerabilities to storm surges whipping in the bay. . Take a further step back and the math becomes even more complicated by this huge factor of how climate change will alter the defenses that communities need.

Specifically: sea level rises as ice caps melt and oceans warm, increasing the size of water molecules.

Amanda Fuller, director of the Texas Coast and Water program for the National Wildlife Federation, said she believes the decade-long debate over Ike’s seawall missed the point. The state is holding back on the conversation that really matters – about reducing emissions, investing in renewable energy and focusing on nature-based solutions, she said.

This project is not going to save the area; it will only save time.

“It’s really been a major distraction, honestly, from how we come up with the band-aid solutions so that we can all get on with living our lives without having to grapple with these much bigger, long-term issues that are really big issues. political issues. at the state level, ”Fuller said, adding,“ This is a band-aid. It is not a quick fix. “

emily.foxhall@chron.com

emily.foxhall@chron.com | Twitter: @emfoxhall


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