West Plains aquifer will be studied

The vast aquifer beneath the West Plains is being depleted by rapidly growing cities and drought faster than it can naturally recharge itself, say state Department of Ecology and Spokane County officials.

Little is known about how much water the aquifer holds or what it looks like underground, so this fall Spokane County will lead a $125,000 geophysical study to assess just exactly what this 12,000-year-old water resource looks like.

“We’re using more water on the West Plains for all purposes than Mother Nature is able to replenish naturally,” said Robert Lindsay, water resources manager for Spokane County.

Rapid growth in Airway Heights and Medical Lake has slowly been depleting the water supply beneath city streets, according to John Covert, a hydrogeologist from the state Department of Ecology’s Spokane office.

Once the study is completed, officials hope to use the results to find new places in the aquifer to drill for water. They’re also hoping to discover which city wells are feeding off other cities’ wells.

This could very well be the case. Fairchild Air Force Base and the cities of Airway Heights, Medical Lake and Four Lakes all have wells along Craig Road, near Highway 902, according to Guy Gregory, senior hydrogeologist for the Department of Ecology.

It is unknown how much longer the aquifer will hold up because no one knows how much water it holds, Covert and Lindsay said.

If the aquifer continues to dry up, the county is looking into pumping water out from the the city of Spokane’s water system or Spokane River.

City and county officials have tentative plans for another study to examine ways to preserve and sustain the aquifer with water from the city of Spokane.

“That whole question of how much (water the aquifer contains) is the $64,000 question, Lindsay said. “We would all like to know. When would it run out? What is sustainable? How can we manage this water resource so our citizens can use the water they need to thrive but also maintain a sustainable balance?”

City and county officials have known about the problem since the early 2000s, when Four Lakes officials noticed their wells were running dry. Soon after, Airway Heights and Medical Lake began experiencing water shortages. There is a separate aquifer beneath Cheney city streets, and it isn’t part of what is commonly referred to as the West Plains aquifer.

“The cities have all recognized that this isn’t sustainable in the long term,” Covert said. “Cities are working on water conservation.”

Indeed, all three West Plains cities have found themselves grappling with how to couple extreme urban growth with a dwindling water supply. .

The aquifer is made of layers of basalt rock and runs about 1,300 to 1,500 feet deep beneath the surface of the West Plains. Water is stored between layers of rocks and in fissures, or beds of gravel or sand, said retired geologist Mike McCollum, whose wife Linda leads research on the aquifer for Eastern Washington University. This kind of subsurface geography for an aquifer extends across the Columbia Plateau and north-central Oregon.

People drill wells into successive layers of the basalt, drilling deeper when water within a layer of the basalt (which is about 100 feet thick) dries up. Medical Lake and Airway Heights have been forced to drill deeper and deeper wells as the layers of basalt closest to the surface dry up.

In February 2007, more than 100 West Plains citizens gathered at EWU to hear several geologists talk about the aquifer’s problems. Many were frustrated or felt angry with their cities for mismanaging sprawling urban growth alongside their water supply. A year and a half later, the problem is still looming large for the area.

In the meantime, a new water main from Spokane to the West Plains is being installed and will extend to Fairchild Air Force Base. The water funneled through that main will be available to cities in the West Plains once agreements have been made with the city of Spokane. Cities throughout the West Plains are also exercising different ways to conserve water to take the pressure off of their wells.

“It’s remarkable how hard everyone is working on it,” Gregory said. “Everybody’s pulling together.”