This article was published on: 02/9/11 12:00 AM

Water sources scarce in the caldera basin

By Erik Hidle / The Bulletin
Published: January 21. 2011 4:00AM PST

Water in the city of Prineville is a precious commodity due to minimal water below the city’s surface, but officials are working on plans to improve the hand they were dealt in the dry caldera basin.

The main problem for the city is minimal groundwater resources. Wells are either extremely low in flow or dry altogether.

City of Prineville Engineer Eric Klann said a resident in Bend or Redmond can drill a well and expect to produce between 2,500 and 3,500 gallons per minute, but a Prineville resident drilling a well should only expect a fraction of that.

According to Klann, a well producing 200 gallons per minute is considered a “good well” in the Prineville area.

In 2005, the city drilled three wells that ended up being completely dry.

Klann said he is working on developing a map of where underground “streams” are located that could be tapped to develop more abundant wells.

The idea came when the city found a strong source of water near the airport in a vein of basalt aquifer. Two wells in that area produce a total of 1,000 gallons per minute. But a third well, drilled 2,000 feet from the current wells, came up dry showing that the vein is quite narrow.

“What we found is an ancient Crooked River streambed,” Klann said. “Millions of years ago, the Crooked River ran through that area. When we went down in that area, we hit one of those old river channels where the water is still flowing. But the problem is once you move away from that area, you can hit a place where the Crooked River never was.”

The reason the city is so interested in developing better wells is because, as it stands now, the city does not have the capacity to serve its existing residents, Klann said.

Klann said the city currently serves 9,020 people, but some 1,250 residents do not have city water service and use wells to draw their own water.

On top of that, state law requires the city to plan to serve the entirety of its Urban Growth Boundary with services. Prineville estimates it could see 26,980 new residents if the boundary is filled.

Also, the city is restricted in what it can do to solve the water problem as it is included in the Deschutes Groundwater Mitigation Area.

The state-mandated boundary dictates water use in the area and requires mitigation credits to be obtained before additional wells can be dug.

“The credits are expensive and few and far between,” Klann said. “There are no more surface water rights here. If we pump a gallon of water out of the well, it won’t go to the stream. So, whatever water we take out of the stream we put back into the stream.

“We are studying our geology here,” he said. “We are trying to determine how our aquifers are recharged and where the water comes from. We are also trying to identify natural flow water rights so we can convert those into mitigation credits.”

Klann also said projects such as the bill proposed by U.S. Rep. Greg Walden, R-Hood River, to release more water from the Bowman Dam could help them obtain mitigation credits.

“On top of everything, we are very much working on our conservation efforts,” Klann said.

 “The less we waste, the more we have.”

Erik Hidle can be reached at 541-617-7837 or at ehidle@bendbulletin.com.

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