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In September 2008, Hurricane Ike made landfall close to Galveston, Texas, as a Class 4 storm with round 20 ft of storm surge. Regardless that the hurricane brought on greater than $7 billion in injury, it quickly grew to become clear that the catastrophe could have been much worse: If the storm surge had struck the coast at a distinct angle, water may need funneled up the Houston ship channel and inundated the town’s all-important petrochemical hub, to not point out hundreds of houses.
Within the aftermath of the storm, Texas officers looked for a solution to defend Houston from related occasions sooner or later, and so they quickly settled on an formidable venture that got here to be generally known as the “Ike Dike” — a sequence of sea partitions and synthetic dunes alongside the 50-mile-length of Galveston Bay, anchored by a two-mile-wide concrete gate system on the mouth of the ship channel. The gate would keep open throughout calm climate to permit ships to enter and exit the channel, however would shut throughout hurricanes, shielding the town and its oil infrastructure from flood occasions.
The Ike Dike has since turn into synonymous with hurricane resilience in Houston: Native officers have spent a decade lobbying for the venture, and now it’s nearer than ever to turning into a actuality. The U.S. Military Corps of Engineers, the nation’s chief builder of levees and flood partitions, secured congressional approval to maneuver ahead with the barrier final yr. The $31 billion system is the biggest venture that the Corps has ever undertaken, with the gate system accounting for two-thirds of the fee. The company says it’s going to take around two decades to finish.
Regardless of the large scale of the venture, there’s one huge drawback: Consultants say the Ike Dike received’t reliably defend Houston from main storms. The limitations might not really be tall or robust sufficient to deal with excessive storm surge, particularly as local weather change makes the fast intensification of hurricanes extra possible. And even when the barrier does maintain, it received’t do something to cease the form of city flooding that occurred when Hurricane Harvey dropped 30 inches of rain on Houston in 2017. The Corps has lengthy most well-liked to combat hurricanes with massive coastal engineering tasks, however such tasks solely defend in opposition to one sort of flood threat.
Although the Ike Dike can be one of many largest hurricane protection programs wherever on the planet, the Corps’ personal designs recommend it may not be capable to deal with storm surge from Class 4 and 5 hurricanes. The unique Ike Dike idea was the brainchild of a professor at Texas A&M University, who proposed a sequence of 17-foot-high limitations that may ring the whole thing of Galveston Bay, sealing it off from the Gulf of Mexico. One other group of consultants at Rice College later proposed a complementary project that may line the inside of the bay with levees and synthetic islands, offering a second layer of protection for downtown Houston.
The model that the Corps finally settled on is far less ambitious. Its dunes would solely rise 14 ft excessive, decrease than the height storm surge throughout Hurricane Ike itself. The ultimate design additionally leaves a gap on the western aspect of the bay the place surge may enter uninhibited, and it doesn’t name for a second line of protection like Rice’s synthetic island community; the company thought of each choices however determined that they weren’t well worth the cash.
The lowered scale of the venture implies that greater surge occasions may blow by means of the dunes and even overtop the central gates, pushing towards the town simply as Hurricane Ike may have accomplished. The Corps’ personal evaluation discovered that even with the venture, the bay would nonetheless endure a median of greater than $1 billion in annual storm injury. And as sea ranges rise, the limitations will develop much less efficient, ratcheting up the danger much more.
Consultants say the company possible downsized the Ike Dike to adjust to a Reagan-era regulation designed to restrict federal spending. The rule requires the company to conduct a “benefit-cost evaluation” for each venture it undertakes, guaranteeing that the venture will forestall extra {dollars} in future injury than it prices to construct. However the Corps can solely take into account “advantages” that happen within the first 50 years after a venture is constructed, and it couldn’t justify paying for full safety in opposition to massive storms. The gate system may defend in opposition to a significant 500-year flood occasion, as an example, however the dune limitations alongside it’s going to solely present safety in opposition to a a lot smaller 50-year flood occasion.
The company’s cost-benefit constraints imply that the Ike Dike received’t do a lot to guard Houston itself, mentioned Jim Blackburn, an environmental lawyer who teaches at Rice College. Coastal communities like Galveston will get quite a bit safer, however the existential threat to Houston will stay.
“There might be some advantages to the ship channel [and Houston], however it solely actually goes till a sure dimension of storms,” mentioned Blackburn. “There’s a brand new actuality for the longer term, and the Corps just isn’t as in a position to answer that sort of evolving threat.”
In response to queries from Grist, a spokesperson for the Military Corps of Engineers defended the Ike Dike venture, saying it could scale back injury from medium-size hurricanes by as a lot as 77 p.c and forestall a median of $2 billion in damages every year, although “residual threat” will stay.
“The funding [in the Ike Dike] pales compared to the tons of of billions of {dollars} in devastation the Texas coastal communities would incur by a direct hit of a number of large hurricanes,” the spokesperson mentioned. “There is no such thing as a different proposal which meets the federal authorities’s strict necessities, might be accomplished in the timeframe proposed, [and] has Congressional approval.”
Even when the Ike Dike does turn into a actuality, Houston is way additional behind on addressing flood threat that doesn’t come from the Galveston Bay. When storms move over the Texas coast, the rain they drop drains out into the Gulf of Mexico. Because it strikes towards the ocean, this water flows right through Houston alongside serpentine waterways referred to as bayous. These bayous run previous tens of thousands of homes, a few of them mere ft from the water. The most important of them, Buffalo Bayou, passes proper by means of downtown.
The Corps itself is to blame for some of the flood risk on Buffalo Bayou. Again within the Thirties, the company tried to regulate flooding on the waterway by building two dry reservoirs that may lure water throughout huge storms, holding it again from the town’s downtown. However the company didn’t carve out sufficient land to retailer the water from a mega storm like Harvey, and builders later constructed a number of subdivisions on land that the Corps knew would flood. When these subdivisions stuffed up with water throughout Harvey, owners sued the company for damages and received a settlement that could exceed $1 billion.
Even because it strikes ahead with the Ike Dike, the Corps is on the lookout for a solution to management this city flooding as effectively, however it doesn’t have many good choices. Its preliminary proposals to line Buffalo Bayou with concrete and build a third dry reservoir on the open prairie exterior Houston fell aside amid considerations about environmental impacts. The company’s different huge concept, which has garnered some assist from Houston-area flood officers, is to dig a giant stormwater tunnel between the flood-prone metropolis and the Gulf of Mexico, funneling extra water underground earlier than it might inundate city Houston. However this venture, too, faces important challenges: The tunnel system would value as a lot as $12 billion and would take greater than a decade to construct.
The Corps’ tasks additionally neglect the town’s different bayous, most of which run by means of Black and Latino neighborhoods, in keeping with Susan Chadwick, the director of Save Buffalo Bayou, an area environmental nonprofit. Chadwick argues that the company ought to spend cash on grasslands and inexperienced areas that may take in water throughout the town earlier than it results in the bayous within the first place, slightly than attempting to regulate these waterways with engineered “gray infrastructure.”
“We imagine in stopping storm water earlier than it floods the streams,” mentioned Chadwick. “We have to deal with slowing and holding water the place it falls, and we want extra particular person and neighborhood efforts to cease and gradual and unfold out and soak in stormwater.”
The Corps doesn’t are inclined to fund that form of inexperienced infrastructure, Chadwick mentioned, and deprived neighborhoods usually lack the political clout to advocate for main federal infrastructure investments. Houston and surrounding Harris County have raised some cash for native flood-control tasks, together with by means of a 2018 bond issuance, however with out federal {dollars} will probably be onerous for the town and county to maintain up with the danger. (The Military Corps of Engineers didn’t reply to questions on its inland flooding tasks earlier than publication.)
Houston just isn’t the one place the place the company has proposed to mitigate hurricane threat with formidable engineering tasks. Corps officers have pitched massive sea-wall buildings to a number of different cities which might be weak to hurricanes and storm surge, together with Norfolk, Virginia, and Charleston, South Carolina.
In some instances, locals have spurned the company’s tasks for being too costly or dangerous to the atmosphere. Officers in Miami not too long ago rejected the Corps’ plan for a wall that may have blocked ocean views, and environmentalist teams in New York torpedoed plans for a five-mile gate construction that may have spanned the 10-mile bay between Lengthy Island and the Jersey Shore. The Corps returned to New York final yr with a $52 billion plan to build 12 smaller gates, however the identical teams have rejected that plan as effectively, saying it nonetheless focuses an excessive amount of on storm surge slightly than on sea-level rise and neighborhood flooding.
Texas has gone the alternative route, embracing the Corps’ deal with grey infrastructure. As Blackburn sees it, these tasks will go away Houston a great distance from fixing its hurricane woes.
“Houston is an engineering city, and it is a big-time engineering answer,” he instructed Grist. “However I feel what you see is an company that’s working with ideas from the Eighties going through Twenty first-century flooding issues.”
This text initially appeared in Grist at https://grist.org/extreme-weather/houston-ike-dike-army-corps-flooding/. Grist is a nonprofit, impartial media group devoted to telling tales of local weather options and a simply future. Study extra at Grist.org
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