This article was published on: 01/10/12 12:00 AM
Surface and groundwater sources a boon for Bend
By Frank Turek
Published: January 05. 2012 4:00AM PST
I am in support of the surface water improvement project. I am a hydrogeologist who worked on surface water and groundwater resources planning and water supply development for 30 years before retiring.
I know of no community that gave up a significant renewable surface water supply. However, I know of many communities that spent millions — and in one case billions — of dollars to develop surface water supplies to augment groundwater supplies. Bend, with its dual surface water and groundwater supplies, is the envy of many communities in the arid Western U.S.
Opponents of SWIP claim drought will impact the surface water, making the project of limited use. What they don’t say is that snow replenishes both the rivers and groundwater. They also don’t tell you that the base flow of both Bridge Creek and Tumalo Creek comes from groundwater via springs. If there is an extreme drought, both surface water and groundwater will be impacted.
Bend has surface water rights dating back to the early 1900s. If Bend switches to all groundwater, the new rights would have priority dates of 2012 or later. When there is a drought, reductions in water use are mandated by the state and rights with the latest dates are cut first. If Bend has 2012 or later priority dates, they would be cut first. That is not opinion, it is the law. Other states like Idaho have restricted groundwater use during drought.
It makes much more sense to have two water sources so any shortages can be shared rather than making all cuts to one supply.
Opponents often cite the billions of gallons of annual groundwater recharge. What they don’t tell you is groundwater moves through cracks in the rocks. There is no huge pool of underground water. In Central Oregon, the groundwater generally moves from the southwest toward the northeast. Groundwater that does not flow beneath Bend is not available to the city. Only a portion of the billions of gallons of groundwater is available for use by the city.
The opponents want Bend to switch to all groundwater but do not say what the impacts of this additional pumping will be. Bend would have to pump 13,000 acre-feet of groundwater a year to replace the surface water supply. An acre-foot is equal to the water to cover a football field one foot deep. They don’t talk about what effect pumping 13,000 football fields of water could have. The U.S. Geological Survey prepared a computer model of the groundwater and surface water and groundwater interaction in Central Oregon. Its model shows the Deschutes River through Bend is a losing stream, meaning a portion of the surface flow seeps into the ground to replenish groundwater thus diminishing the Deschutes flow. The USGS model showed additional pumping would increase the seepage and depletion of surface water flow. So switching to all groundwater could have impacts on the Deschutes through Bend and the Lower Deschutes downstream. This is why the state created the mitigation program.
Opponents say the Deschutes depletion could be offset by mitigation. That is true. I worked on groundwater mitigation recharge projects and they cost millions of dollars. A common form of mitigation is to buy and retire farmland for the water rights. Bend would need to purchase 3,000 acres of farmland to mitigate 13,000 acre-feet of new pumping. These mitigation costs are overlooked by SWIP opponents as being a part of the true cost of groundwater.
I support the surface water project and commend the City Council for its decision to proceed with the project to have a dual potable water supply to provide for the health and safety of the public for decades into the future.
— Frank Turek lives in Bend.
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