I don’t actually know what underlies the Middle Devonian brachiopods of my childhood, but I might get to find out soon. Iowa City is experiencing its second “500 year” flood in 15 years, and Coralville Lake has overtopped its dam… again. And the river hasn’t crested yet. Fortunately, my family is on high ground, and playing host to some friends who’ve been evacuated from the flood zone.
Buildings in Iowa City must have floors that are at least 1 foot (or 1.4 of your Earth football diameters) above a designated “100 year” flood elevation. These elevations are determined by FEMA; climate records and projections are fed into hydrologic models to determine water elevations during freakishly wet years. Whether we’re just having a statistical freakout, or whether the amount of rain that FEMA expects to occur in a 100-year flood needs adjusting… are there hydrologists or climatologists in the audience? This is beyond my expertise and I’m not in the mood to wade through the literature tonight.