Then Willem pointed his truck toward New Orleans. He passed up an opportunity to jump on an interstate, preferring an old two-laner. The landscape was flat by American standards, but not by Dutch. The usual American roadside scene of convenience stores, mobile home parks, and equipment depots interspersed with wooded areas. On the map it looked like a sponge, with water
coming practically up to the road, but if you didn’t know that, it would just look like normal dry land, exuberantly green, with a lot of trees. His practiced eye noted that the bed of the road was elevated a couple of feet above the surrounding earth.
A few miles short of New Orleans, he came to the Bonnet Carré Spillway, which was not much to look at but was probably at the top of the list of must-see attractions for the climate change tourist. Here all the roads and railways had been funneled into the five-mile-thick isthmus separating the Mississippi’s left bank from Lake Pontchartrain. Running athwart all that was a mile-wide sluice connecting the two. Or rather it was capable of doing so when it was opened. A hundred years ago they’d constructed a spillway barring its Mississippi end. This was a palisade consisting of seven thousand massive vertical timbers arranged vertically in a frame of concrete and steel, deeply anchored in the river’s bank. To one side, these were scoured by the flow of the Mississippi. To the other side was what passed for dry land: a wetland stretching from there to the lake, striped with drainage ditches and speckled with puddles and ponds, passing beneath elevated highways and railroads.
The summed pressure of the Mississippi water on the vast palisade must have been huge, but the pressure on any one single timber—they were about the size of railroad ties—was modest enough that it could be pulled up to create a slit that would let some water through. Rail-mounted cranes moved along the top of the frame pulling the timbers up or pushing them down to regulate the volume of flow diverted from the river into the sluice and thence to Lake Pontchartrain, which had its own outlet to the Gulf of Mexico.
They’d built all this after the terrible flood of 1927, which had inspired the blues song “When the Levee Breaks.” It was intended as a safety valve, a bypass to be opened at rare moments of dire need, when heavy rains falling upstream—which was to say anywhere between the Rocky Mountains and the Alleghenies—had swollen the river to the point where it was threatening to overtop or burst through the levees and inundate New Orleans. Several times in the ensuing ninety years it had been used just as planned.
But then in 2019 they’d been forced to leave it wide open for four months because of a wet winter. Other years since had not been quite as bad as that, but 2019 had inaugurated a new pattern, which was that the spillway was partially open more often than not.
For all its immensity, you could drive right over the Bonnet Carré Spillway and not take note of it. You’d see the water under the causeway, of course. But around here there was a lot of water.
The Mississippi was about seven Rhines. When this spillway was wide open, it diverted two and a half Rhines into the lake.
Now, where Willem came from, a Rhine was sort of a big deal. A third of the Netherlands’ economy passed up and down one single Rhine. They had, in effect, built a whole country around it. Here, though, people were gunning their pickup trucks over a causeway bestriding two and a half Rhines just as a temporary diversion of a seven-Rhine river over yonder. It was one of those insane statistics about the scale of America that had once made the United States seem like an omnipotent hyperpower and now made it seem like a beached whale.
Willem pulled off the highway onto an access road leading to the spillway, just so he could check his messages and spend a few minutes watching the cranes gliding along pulling the wooden timbers up. It had been a wet year to begin with. Now, rains in the hurricane’s wake had sent huge flows coursing down the Mississippi and so they were opening the spillway full bore. He got a few curious looks from the workers, but once again the white pickup served as industrial camouflage.
Hugh was on vacation in some cooler and drier clime, but he referred Willem to Dr. Margaret Parker, a colleague in the same department at Tulane, who agreed to have coffee with him. Ten years ago they would simply have met on the campus, but her lab had been downsized in the pandemic and never re-upsized, and she worked out of her home. It was just as convenient for her to meet him at a café in the French Quarter. She knew of a place with a second-story, open-air gallery that looked out toward the river.
The Bonnet Carré Spillway, which he now put in his rearview mirror, was the upstream bulwark of The Wall, aka HSDRRS （Hurricane and Storm Damage Risk Reduction System）： a system of flood defenses, largely invisible to the non-expert observer, that encircled greater New Orleans. Dutch experts had been brought in to consult, and this was how Willem had come into occasional contact with people like Hugh and Margaret.