Last week the Governor's Commission studying the Hurricane Ike recovery unanimously recommended to the Governor and the Legislature that a study be funded to determine the feasibility of a comprehensive levee system to protect the Texas Gulf Coast from future storm surges. The recommendation was prompted by presentations made to the Commission by Texas A&M of a concept levee system that would block storm surges from entering Galveston Bay. The proposed system has been dubbed the "Ike Dike."
To be perfectly honest, when I first heard the idea, I thought it was a bit outlandish. But as the Commission has studied the issue, all of us became convinced that the concept warrants a serious and detailed consideration.
The Ike Dike is the brainchild of Texas A&M Galveston's Bill Merrill. To review his PowerPoint presentation click
here. The dike envisioned by Merrill would extend from High Island to somewhere south of the San Luis Pass and is specifically designed to protect the Galveston Bay environs. However, the Commission's recommendation is that a study that would include the entire Texas Gulf Coast.
The project would basically create a 17-foot wall along its entire length, incorporating the existing Galveston seawall. There are several possible designs, but the one that probably is most viable would be building a levee along the existing FM3005 and SH87 right of ways. These are already at about a 5-foot elevation, so they would only have to be raised by twelve feet to get the design elevation.
Of course, the challenging part is how to keep the surge from barreling up Houston Ship Channel through the Bolivar Roads. This will require creating a gate that will close off a nearly two-mile stretch of open water. As bizarre as this may sound, there is actually such a barrier across the Rotterdam channel in the Netherlands that spans a wider gap.
Clearly, we do not have enough information at this time to make an informed judgment on the feasibility or advisability of such a project.
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Bolivar Roads
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However, the Commission did ask some basic questions. This is what we found.
Cost. The obvious questions are "how much" and "how would we pay for it." Merrill estimates that the Galveston Bay portion of such a levee would cost about $3 billion in today's dollars. This frankly would be a fairly modest investment comparatively speaking. The estimated damage from Ike alone is in excess of $30 billion. Not all of the damage would have been prevented by such a levee system, but clearly it would pay for itself with just one such storm. It is also comparable to other major public works projects in this area. The expansion of the Katy Freeway and Metro's LRT project both have similar price tags.
The federal government would likely be willing to substantially subsidize such a project since it would dramatically reduce claims on the Federal Flood Insurance Program. But even if Texas had to pay for the project alone, it would only take about 5-6¢ property tax on the affected counties to finance the project over 30 years. I think it is clear that if Merrill's cost estimates are anywhere close to accurate, the financial hurdle may the lowest one.
One of the more disturbing pieces of information the Commission heard was that industrial and commercial concerns are now reluctant to invest along the Gulf Coast because of its vulnerability to storm surge. It may be that if we do not undertake some protective measures, we will see economic growth stunted in our region by an amount far greater than the cost of such a project.
Will it Work? A number of Commission members were skeptical about whether such a levee could really hold back a Category 5 storm surge. Merrill points out that the Dutch have been holding back the North Sea for centuries, a seemingly more daunting task.
Some of the Commission's questions centered on whether a 17-foot levee was high enough. At places the Katrina storm surge was measured as high as 28 feet. However, the 20+-foot measurements are all inland and not at the coast. A storm surge is exaggerated as it pushes its way into the confines of bays and rivers. According to Merrill, a 17-foot system will stop 95% of the storm surges ever measured. Also, even if a storm surge topped the levee, the effects on the inland areas would still be dramatically minimized.
Environmental Impact. The environmental impact of such a levee system will be the most vexing question. There are obvious and significant environmental benefits. One only need visit Galveston Bay today to see the adverse impact of Ike. Also, friends in the petrochemical industry have told me that if we ever get an Ike-like surge directly up the Houston Ship Channel the ecological consequences will be disastrous; which is easy to believe.
On the other hand, there could be adverse long-term, and perhaps, unintended consequences from constructing such a system. Some environmentalists argue that hurricanes actually have a long term beneficial effect on the estuary system.
One of the concerns raised immediately by environmentalists is the effect on the exchange of water flows between Galveston Bay and the Gulf. In order to build the sea gate that would close off the Bolivar Roads, the opening would have to be narrowed from the current width of nearly two miles to about 1000 feet. Environmentalists worry that this stricture would impede the flow of Gulf water into the Bay along with various species that migrate between the Gulf and the Bay. It might also alter the salinity of the Bay and thereby negatively impact some species.
Merrill is convinced this concern can be addressed by designing the dike to accommodate a sufficient Gulf water inflow. But even if that is the case, there will be many other environmental concerns such a massive project will raise. Part of the vetting process must address each of these with scientific integrity.
Conclusion. Thanks to Ike, I experienced first-hand the effects of a storm surge on my hometown of Kemah. I also remember returning to a nearly totally destroyed Kemah as a child after Hurricane Carla. Therefore, I am probably not entirely objective on this subject. Nonetheless, I have seen the human and financial toll a storm surge has on families and communities. It is truly devastating. If we can responsibly protect future generations of Texans from hurricane storm surges, it would be a great legacy to leave our children and grandchildren.
