For those of us in earth science, this past week has highlighted an awful lot of potential “told you so” moments. Like how warming climate and a warming ocean will lead to higher precipitation events. Like how you really do need to plan for floods. And we just missed hearing more about the barrier island/marsh protection talking point. And almost at the same time we’ve been greeted with ever more evidence that the Trump administration has little or no use for scientific input–not even choosing to ignore it, they seem more eager to simply not have any scientific input at all. Just as it is ever clearer that we are facing real decisions in trying to prepare for a warmer world, we seem the have a government yelling “la la LA LA” with its fingers in its ears.
But that isn’t the point here today.
One aspect of the tragedy in Houston is that the absence of any sensible planning has led to more flooding (the worst example might well be letting houses be built within the basin and below the spillway elevation of flood control dams); this is exacerbated by the combination of government subsidized flood insurance and the out-of-date or inadequate flood zone maps. Of course some now point to the zoning-free and laissez-faire approach to building in Texas as the bargain they made with the devil, implying that other places where strict zoning has been enforced will be safer.
If GG has noticed one thing about strict zoning (and Boulder has a pretty heavy hand on building), it is that it is rarely used to prevent building in stupid places–it is mainly used to keep people from building on land other people enjoy as it is. Some years ago when Colorado Springs was approached by a developer who wanted to build houses on an active landslide, the city council had to look away from the evidence they were given in order to approve this ongoing disaster. You can find similar stories elsewhere. Yes, fear of flooding is brought up when a new development is proposed…but mainly as part of the larger arsenal serving Fort NIMBY (sometimes there is a legitimate fear, but sometimes it is greatly exaggerated). California has the Alquist-Priolo act to prevent construction near active faults, but it only moves buildings 50 feet from an active fault. Direct destruction of a building by a fault being directly under it is one of the least likely modes of destruction (even some dams do OK on faults: the Upper Crystal Springs dam survived having several feet of offset in the 1906 earthquake). Earthquakes do most damage by shaking weak soils: recall the Marina District in San Francisco, far from surface faulting, where shaking from the Loma Prieta earthquake damaged dozens of structures. What strict zoning clearly does is raise housing prices.
The main exceptions to non-use of zoning as a disaster preventative is in the wake of disasters. Even then, the most common refrain after a disaster is “we’re going to rebuild and bring it back better than before.” After a tornado, this makes sense. After a flood, whether storm surge or heavy rain? Not so much. The harder statement? “We learned a lesson and we aren’t going to make that mistake again.” It is very hard to say, but if we are going to avoid paying to rebuild over and over again in increasingly vulnerable places, risking the lives of inhabitants in the meantime, it’s time to start saying it and then walking the walk.