A Suburban Nightmare Millions of Years in the Making

    The hole was huge. Gaping, even. From one side to the other it yawned wide in the Earth, fifty feet or more across and deep enough that even the boys of the neighborhood, usually so bold and ready to tackle whatever danger they could find, were dutifully minding their mothers’ instructions to keep their distance. Staring down into the abyss one could see the glint of metal pipes and the jagged concrete which had come from the street previously occupying the space where the hole had developed early that morning. One young girl, remembering a trip to some caves out West the Summer previous and time spent playing amongst stalagmites and stalactites (though she could never remember which was which) had tried to scout around the edge of the cavernous collapse to look for geodes, before being pulled back by her father and sent to her room. Even now as the police placed yellow tape and blockades around the hole, a few brave souls tried to free themselves from the grip of concerned parents for a closer look, though not getting quite as close as they might have done had one very lucky police officer not been saved from being dragged to the bottom as the edge he was standing on collapsed by a local banker who had been close enough to run forward and snatch him from the grimacing mouth of hell that had opened up right in the middle of an otherwise quiet neighborhood. 

Miles away, at city hall, a man in a brown suit and a bad toupee was giving his best explanation of the collapse to the mayor and those who ran the city. “What we have here,” he was saying, “is a case of subsidence.” One of the men in the room raised a hand and the speaker continued without calling on the man: “that is, we have a collapsed aquifer, ladies and gentlemen.” There was a sudden babble of voices as dozen of city officials started talking at once. A woman in a purple skirt raised her hand, and this time the toupee’d man did gesture in her direction. 

“I’m sorry sir, but how can an aquifer collapse? It doesn’t make sense. Also, the aquifer under the town is way bigger than the hole on sixth street.” The man nodded and replied “indeed it is. Let me explain. There are different levels to aquifers. What we have witnessed on sixth street is a collapse of the ground on which we walk into the saturated zone of our local aquifer. Ours is a pretty standard aquifer, a large containment of groundwater fed by losing streams up in the mountains around the town, themselves fed by snow melt in the highest peaks. Our town is built on a huge zone of what we call Karst topography, that is, a table of soluble rock—limestone mostly—that forms of the aquifers and water beds and caverns that make this part of the country famous. We sit atop a tectonic plate boundary which sandwiched the former sea floor of an ancient sea in this region and thrust the marine sediment up into the sky. But not all of that limestone is part of mountains, instead as the city planner Mark Brandanawatz could tell you, we sit on a huge limestone deposit.”

“Well,” he continued, “we’ve had a very dry couple of years, and some very mild Winters. Not a lot of snow, even up in the mountains. The aquifer has become more and more depleted, as you’ve probably read in the papers. The wells have had to go deeper to reach the water table as it experiences drawdown, and we’ve been concerned that we might see the development of a cone of depression along certain high usage areas drawing from the aquifer. There was even a plan floated to put steel columns in a couple of the underground caverns around here, which, as you’ll all remember, our illustrious mayor declared was too expensive. Well, as the water levels fall, houses expand out to areas where water is easier and cheaper to reach. In this case, we built a neighborhood of huge houses right on top of a particularly weak spot where the underlying limestone layer is not particularly thick. We put unnecessary stress on this part of the land, we’ve been overusing an depleting our aquifer, and we’ve failed to plan well. Thus, we end up with a huge hole 100 feet deep which is going to cost millions of dollars to fix. Ladies and gentlemen, we over-tapped our resources, and this is the result. Any other questions?”

All the hands in the room shot up, and the man sighed. It was going to be a long afternoon. At that exact moment, in the middle of Sixth street, the alarm on the 2001 Ford Taurus that had been parked in the middle of what had become a sinkhole finally stopped going off as the battery died, children had become bolder and begun to throw things over the barriers to listen for a splash far below, and dozens of anxious people waited on hold with insurance and real estate agents as the future became more and more uncertain by the minute. And at the bottom of the hole, water ran and seeped through limestone corridors, carving into the stone as it had for thousands of years, not giving even a moment’s thought to the world of humans which had been disturbed far above.