ALL THE DAMS AND MAGIC WETLANDS CAN DO
Big, fat, cleared floodplains are the best way to handle a very large storm, explains wetlands scientist John Jacob — because nothing else is going to: “An average rainfall of 35 inches over all of Harris County (Harvey) is just over 1 trillion gallons. At most, there are about 50 billion gallons of stormwater detention capacity in Harris County wetlands (no one has measured this — I had to make some very broad assumptions). So that means that the wetlands at best could handle about 5% of the total volume of Harvey rainfall. In the large scheme of things, it’s not much. And the scheme of things in Harvey is indeed very large.
So much for the magic wetlands. But what about our engineered drainage system? I calculate a somewhat larger detention capacity — between our large US Army Corps of Engineers Katy Prairie reservoirs (~400,000 acre-ft) and Harris County Flood Control District detention (about 34,000 acre-feet), we have about 130 billion gallons of detention volume. More than what we have for wetlands, but still only about 14% of Harvey. As we painfully saw, also overwhelmed.
And what of green stormwater infrastructure — rain gardens, bioswales, green roofs, etc.? We don’t have any good numbers here, but you can be sure that even if these practices were widespread, the volume would be very small relative to wetlands and detention basins. These practices are designed to capture at best a 2 inch storm.” [Watershed Texas] Photo of Willow Waterhole Greenspace: Luz (license)

The part of Texas “[where] storms are what you talk about” is the subject of John Nova Lomax’s dispatch this week in Texas Monthly — more specifically, the 16-mile stretch of coast where the state gave up on rebuilding SH 87 after the last of a series of hurricane washouts in the 1980s. Amid nude beach signage, dolphin carcasses, and the rusting remains of pipelines and 4-wheelers, Lomax meditates on the idea that the battered stretch of coast, where Texas’s beaches and barrier islands begin dissolve away into a Louisiana-style tangle of eroding wetlands, “once functioned as a seawall: there was a natural ridgeline made of shells and sand that was used as a trail by Native Americans, then Spaniards, then Texans.
Jefferson County’s commissioners are 

“What a waste! The coastal prairies will soon be gone and few will remember them. Everyone will say, ‘Well, Houston doesn’t have much in the way of natural environment anyway, but at least it has affordable housing compared to a lot of cities,’ and ‘Oh yeah, it is hot, but we stay inside most of the time, so who cares about the outside world?’ Maybe Houstonians should be the first to move to Mars or the Moon. (Hopefully) there aren’t any irreplaceable ecosystems to replace with big box stores, suburban homes, and highways!” [