Aquifer water levels not recharging
OTHELLO — Additional information on Columbia Basin aquifers confirms water levels are not recharging.
Columbia Basin Ground Water Management Area (GWMA) representatives met with Othello officials and citizens last week to inform them about the issue concerning their city and surrounding cities. GWMA represents Adams, Douglas, Franklin and Grant counties.
“It’s mostly old, ancient water that isn’t being recharged,” GWMA Executive Director Paul Stoker stated. “With up to one million acre feet being withdrawn from the aquifers each year, it will continue to decline. If you live here, you need to understand how this impacts you and the future of our communities.”
Information about the declining aquifers was gathered by mapping basalt layers from areas referred to as Saddle Mountain and Wanapum, stated hydro-geologist Kevin Lindsey. They’ve been mapping the layers to track water levels.
They reviewed several aquifers including the Grand Ronde, Wanapum and investigated Lake Roosevelt.
“Lake Roosevelt literally sits on top of granite bedrock, which also underlies the basalt aquifer system,” Lindsey stated. “Unfortunately, the lake is also hundreds of feet below where the basalt layers protrude and are exposed to recharge. Clearly, Lake Roosevelt is not recharging the Columbia Basin basalt aquifer system except maybe locally in small areas.”
Geo-chemist Dimitri Vlassopoulos analyzed 44 wells throughout the Columbia Basin to determine the age of the water and their possible connections to other water bodies.
“Most of the water in the lower Grand Ronde aquifer, generally between 1,000 and 2,500 or more feet below the ground surface is more than 10,000 years old, with the last recharge coming from the ice age, which covered this area and saturated the geologic system,” he stated.
“Today, the deep Grand Ronde aquifer receives virtually no recharge and is declining the fastest. This is especially true in the center of the GWMA where these deep zones have little or no direct connection to the ground surface.”
Vlassopoulos stated he reviewed city wells in Royal City and Moses Lake and found deeper aquifers are declining.
“Both reveal the problem that is typical in the heart of the basin, over-pumping is driving a race to the bottom that no one will win,” he stated.
Hydrologist John Porcello shared his findings concerning wells he’s researched in the Columbia Basin.
There is little to no vertical movement between basalt aquifers, the aquifers are separate from each other and the Grand Ronde is declining.
A small amount of natural recharge is reported on the outer rim of the Columbia Basin but it does not appear to travel far, Lindsey stated.
“Recharge is occurring in the upper basalt zones, primarily in the Roze, Saddle Mountain and Wanapum and is largely dependent on proximity to surface water, be that a natural water source, such as a lake or stream, or an artificial one, specifically irrigation canals,” he stated.
“We need a model to tell us what to do,” Stoker stated. “We need to come up with a solution because we can’t keep drilling deeper. The aquifer is declining and it isn’t coming back on its own.”
Using data prepared by GWMA, there may be an effort underway to secure state funding to find a solution to the declining aquifers.
Information about the data will be posted on cbgwma.org by Feb. 1.