Williams' Search For Groundwater Complicated By Geology

By Melissa Sevigny
Published: Thursday, July 2, 2015 - 11:31am
Updated: Thursday, July 2, 2015 - 11:43am
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(Photo by Melissa Sevigny - KNAU)
The view from the Sweetwater drilling platform, looking toward Interstate 40 and Williams.
(Photo by Melissa Sevigny - KNAU)
Fill material removed from the borehole shows the colors of the different rock formations.
(Photo by Melissa Sevigny - KNAU)
Contractors work to repair the borehole with cement.

The unique hydrology beneath the city of Williams makes their search for groundwater difficult. But other towns on the Colorado Plateau may have to learn from their experience.

Williams, west of Flagstaff, is in the process of drilling a new well. Like many places in the Southwest, it’s facing drought and rising demand. But there’s another reason water supply is a challenge in Williams -- a fluke of geology has forced the city to take the lead in the hunt for groundwater on the Colorado Plateau.    

Pat Carpenter is a consultant for the Williams City Council. He’s standing on the drilling platform at the Sweetwater well site just off Interstate 40.

“They’re pouring concrete into the hole because we had some borehole issues,” he said.

He’s not surprised to see that things aren’t going as smoothly as planned.

“The main driller here has drilled in, I think he told me, 45 states and overseas, and this is by far the worst place to drill,” Carpenter said.
 
That’s largely the fault of geology. The groundwater here is so deep that the city had to hire a drilling company that typically digs for oil and gas, not water.

“These guys will drill 12 or 15,000 feet for oil,” said Carpenter. “We’re lucky enough we only have to go 3,000 feet for water, if you call that lucky.” 

Most towns on the Colorado Plateau can find water just 1,000 feet down. That’s because they tap into the “C-aquifer,” named for a thick band of Coconino sandstone. Flagstaff, Holbrook, Winslow and towns across the Mogollon Rim all draw water from it.

Williams, however, can’t, because the C-aquifer beneath the city is dry.

“As you move from Flagstaff westward toward Williams, water in that C-aquifer system is migrating deeper into the subsurface,” said Don Bills, a hydrologist with the U.S. Geological Survey in Flagstaff.

Bills said to reach groundwater Williams has to drill past the C-aquifer into the Redwall-Mauv aquifer, a layer of limestone about 3,000 feet down.

“You have to go much deeper to find another regional groundwater flow system,” he said.


The Redwall-Mauv aquifer is so deep it feeds springs in the bottom of the Grand Canyon and so wide it extends beneath most of the Colorado Plateau. So far, few cities or towns have had to resort to using it. Bills said that’s something that might change.

“We’ve definitely moved into a drier climate trend,” he said. “Most of the communities in northern Arizona and throughout Arizona are going to start having to make adjustments to match those trends.”

If they tap into the Redwall-Mauv aquifer, they’ll have to learn from Williams’ experience. The aquifer is highly fractured, which is good for finding water, but challenging for drillers.

And even if you reach groundwater -- which they haven’t yet at the Sweetwater well site -- it’s not a cure-all for a long-term water supply. A recent study using NASA satellite data showed more than half of the world’s largest aquifers have declined in the last decade, stressed by human demand. 

“There’s no doubt that water is becoming an issue, all over the country, particularly in the Southwest,” said Williams Mayor John Moore. “I’m hoping we’re getting out ahead of the curve, and we may be the frontrunners to at least taking care of it locally.”  
 
Moore said the difficulty of finding water has given the city a collective sense of conservation. The City Council recently voted to raise water rates on residents and businesses to cover the cost of new infrastructure. Williams also reuses treated wastewater on the local golf course. Mayor Moore himself practices water conservation in the restaurant he owns downtown.

“At night when we close down any water we’ve got left in glasses or pictures we pour on our  plants and trees,” said Moore. “You do everything you can to conserve water. It’s the mindset of everybody in the Southwest, or should be.”

Once it reaches water, the Sweetwater site will be one of the deepest wells in the state.

Communities across northern Arizona could have a lot to learn from the challenges that Williams has faced.

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