Come ride along as we journey through a dryland conundrum…
“Little by little the sky was darkened by the mixing dust, and the wind felt over the earth, loosened the dust, and carried it away. The wind grew stronger. The rain crust broke and the dust lifted up out of the fields and drove gray plumes into the air like sluggish smoke…” John Steinbeck [The Grapes of Wrath (1939)]
We top out after a long climb from a river that sometimes flows from Mexico into Arizona, dodging past loaded semi-trucks gearing down into rising side winds. I’m eyeing the darkening sky ahead. It’s been over a year since last it rained enough for the arroyos to flow. The roadside mesquite trees dropped their leaves many months ago, waiting for rain. Ahead lies a valley with no visible natural drainage, a basin with a dry lake bed (‘playa’ in the parlance of the drylands). Beyond is a range of mountains known as ‘sky islands.’ I once held title to a small plot in the hills below them, with an arroyo that fed the valley when it rained. Below the valley, collecting groundwater that seeps through the sedimentary layers of ancient erosion from the mountains, lies an aquifer.
This first map shows 62 principal aquifers identified in “The Ground Water Atlas of the United States,” as updated in 2003:
Map from the United States Geological Survey report: Principal Aquifers of the United States
In recent centuries, the lake bed would often sport a massive, shallow lake in the valley’s lowest point, giving me a temporary lake view from my patch of desert. Willcox Lake, the locals called it, and told how some World War II-era pilots in training tried to land a float-plane on the barely covered mudflats. It didn’t go well, they said. Beyond the lake bed to the south, two sulphurous springs gave the valley its name. Like the lake, they are now a dry memory in a name. Increased groundwater use, mostly to feed corn, cotton, alfalfa, almonds, apples, and whatever else can grow a crop with little rain and ample irrigation, soon followed by deeper wells drilled into the aquifer below as local farms were sold to ever thirstier agricultural investment concerns, have drawn down the valley’s water table and created yearly dust bowl conditions, that sometimes close the interstate highway east of here. A dust storm catches us at a Willcox truckstop, blowing tumbleweeds and bits of trash, the grit scouring signs and paint jobs, filling our nostrils with former topsoil…
The Sulphur Springs valley is an extreme example of a nationwide phenomenon illustrated by the maps above and below, which are available as public domain documents as a result of research funded by you and me, through the US Geological Survey. The rates of withdrawal and recharge vary by aquifer and by year, but these are essentially the water banks that we all depend upon, for food production and (ever more in recent decades) for extraction and processing of oil, gas and various minerals.
Maps above and below are from a USGS report: Secondary Hydrogeologic Regions of the United States
In sedimentary layers above, and in the fractures and gaps of less-permeable rock surrounding principal aquifers, are less well mapped but heavily tapped stores of water, called ‘secondary hydrogeologic regions’ or ‘secondary aquifers’. Community and private wells dot the map below, showing where above-ground water isn’t sufficient for human needs, desires, and commercial interests. In 2015, about 84,600 million gallons per day (Mgal/d) of groundwater were withdrawn by wells scattered across the US, with 94 percent of it coming from principal aquifers.
News stories periodically visit scenes of drought and aquifer drawdowns, from the Ogalalla (8 High Plains states from South Dakota to Texas) to the Powder River/Williston (Wyoming-Montana), and in my region of recent rambles, the San Luis (Colorado), the Santa Cruz and Sulphur Springs (both Arizona) aquifer systems are all facing the same conundrum, just who and what will get the dwindling water, as droughts get longer and wells drill deeper.
With a favorable weather cycle and some luck, summer monsoon rains will slake the dust and the Sulphur Springs valley will once again put on a green caste, but on the day of our shared journey, dark dust clouds already obscure the playa and mountains beyond, as southerly winds lift plumes from dry fields, raising the specter of Steinbeck’s descriptive introduction to a climate disaster. I led you here, hoping that when you read or hear of dropping water tables in your own region, when you consider plans to draw straws in the name of production, progress, need and desire (on your behalf or not), that you’ll dig a little deeper into the issues, and try to see what may be lost. We all spend an inordinate amount of time monitoring pronouncements and press releases, when much knowledge is on the land and in our possession already, if we know where to look.
A short postscript, if I may. The dust storm journey I took you on happened in 2021, just a few weeks before the summer rains did come, and I’ve since passed through that valley just after flash floods had inundated whole stretches of country roads and croplands. But the water table continues to drop, faraway investment interests punch straws ever deeper, and local residents’ wells keep going dry. On my last trip through, roadside political signs sloganeered for and against a proposal to form Active Management Areas to regulate groundwater pumping in the Sulphur Springs valley, in hopes of slowing the withdrawal rate of the commonly held water assets. It seemed a close call which way it would go. As I write, votes are being cast.
Here are two well-reported stories from High Country News about the Sulphur Springs Valley’s current dilemma, and an in-depth look at the deep well phenomenon.
For more discussion of primary aquifers and secondary hydrogeologic regions, here’s a study from the journal, Groundwater.
Up next, Apples, Peaches, ‘n’ Pomegranates: on the dry side of sustenance. Take care of yourself, and help someone else if you can. -B