by Nancy L. C. Steele
Within a few months of buying my house near Cottonwood, I turned on the tap and nothing came out. This was a shock! Who do I call to get the water flowing again? I moved here from a big city but now I didn’t have a water company. I had my own well. So, with a lot of anxiety about costs, I called in a well drilling company. After looking at my system they told me that, while I didn’t need to drill a new or deeper well, I did need a new well pump.
This was an expensive introduction to owning my own well. Naturally, I had questions. Where does our water come from? If you pay a water bill, you may think that your water comes from the City of Cottonwood, Camp Verde Water System, American Water Co, or another water company. And you wouldn’t be wrong, as your water travels through pipes owned by those companies. But that’s not the whole story.
The water that we drink comes from underground. In fact, all our drinking water, in much of Arizona outside Phoenix and Tucson, comes from underground aquifers – what we call groundwater. Even the water companies have their own water wells. Most fresh water on the planet, in fact, is under our feet.
We don’t get our drinking water from the Verde River. Here in rural Arizona, we don’t get any water from the Colorado River, either. That water goes to metropolitan Phoenix and Tucson, plus farmers in Maricopa, Pinal, and Pima Counties. In another column we could talk about why that is. But the subject of today’s column is the water beneath our feet.
Out of sight, difficult to understand, all but invisible until we pump it to the surface, groundwater is a hidden treasure. The vast majority of the fresh, drinkable water on Earth is groundwater.
Where does our water come from? I’m not a geologist or hydrologist, so I turned to some experts.
One of the resources any resident of Yavapai County and the Verde Valley should read for groundwater questions is the Well Owners’ Guide to Ground Water Resources in Yavapai County, by Arizona Cooperative Extension. This is a good publication if you want to understand water quality, but it isn’t very illuminating when it comes to water quantity or supply.
It does include a nice map, however, illustrating the geology of Yavapai County. I learned that underneath our feet is a geologic feature called the Verde Formation, which is found on both sides of the Black Hills along the Verde River and in Chino Valley.
What exactly is the Verde Formation and what does the Verde Formation have to do with water?
I found a short pamphlet from the National Park Service, Geology of the Verde Valley. This handy two-page guide was issued by Montezuma Castle and Tuzigoot National Monuments. From the NPS, I learned more about the Verde Formation. It consists of ancient lake deposits made up of limestone, gravels, silt, clay, salts, and travertine. All those white rocks? Verde Formation.
How did those white rocks form? From eight to two million years ago, the Black Hills rose, and flowing water eroded the rock formations that were already here, and which you can see in Sedona and on the Mogollon Rim. Over millions of years, lakes and marshes laid down over 3,000 feet of limestones and siltstones. Those make up the rocks of the Verde Formation.
What does that have to do with water supply? In a 1962 paper by F. R. Twenter, titled Rocks and Water in Verde Valley, Arizona, I learned that of all the rock formations in northern Arizona, only the Verde Formation reliably yields quantities of drinkable water.
Not only is the Verde Valley a beautiful place to live, but it also happens to be the best place to find fresh, drinkable groundwater in northern Arizona.
This year, the theme of World Water Day (March 22) is groundwater, which is particularly appropriate for all of us. If you’ve read this far, I’d like to suggest you take part in the World Water Day “One Minute Challenge.”
Make the invisible visible! Shoot a one-minute video about groundwater. Tell a story about how groundwater affects your life. Share your story about how we couldn’t live in this beautiful place without groundwater. You can find the guidelines at https://www.worldwaterday.org. Share your video on social media and tag it #mygroundwaterstory, #verderiver, and #worldwaterday. The deadline is November 20, 2022.
Take a moment to celebrate groundwater and the Verde Formation! You can learn more at https://verderiver.org.
Watch this short video on groundwater and World Water Day 2022:
This article was originally published in the print editions of the Cottonwood Journal and the Camp Verde Journal on March 23, 2022.