Cascade Aquifer

Background

Central Oregon relies heavily on streams and snowmelt from the Cascade Mountains, which feed into the McKenzie and Deschutes Rivers. Recently, researchers uncovered a surprising new water source in the Cascades. It is a previously unmapped aquifer believed to contain over 80 cubic kilometers of water beneath the Central Cascade range. To put that in perspective, that is potentially three times the volume of Lake Mead – the largest reservoir in the United States.

Research

In an interview with OPB, Lief Karlstrom, associate professor of earth sciences at the University of Oregon, explained. While scientists have long known the Cascades store significant water, it was not until this intensive study that they began to understand just how much. The project initially aimed to “better understand” the region’s landscape. It led to the discovery of a massive, untapped reserve.

Researchers revealed that the Central Cascade arc shows a strikingly consistent connection between topography and hydrology, tied to aging volcanic bedrock. These findings suggest that geologic structures in the region have directly shaped its water systems over time.

Discoveries of the Cascade Aquifer Erupt

Formed by volcanic eruptions and gradually uplifted by magma flows, the Cascade Mountains are underlain by rock with unexpected water-holding properties. According to Karlstrom, when volcanic rock becomes heavily fractured, it can store and transmit substantial amounts of water. These fractures allow water to seep and move through the subsurface in surprising ways.

This groundbreaking discovery came as researchers focused on what they call the “critical zone”. This is the near-surface region where atmospheric forces meet the solid Earth. By analyzing geothermal wells drilled decades ago, scientists were able to map temperature gradients and trace the extensive flow of water through the volcanic rock.

Conclusion

Although the study was originally designed for energy exploration, the findings have opened the door to a new understanding of Oregon’s subsurface water supply. Scientists note that the existing wells may not show the full extent of the aquifer. This means that the volume of water could be even greater than the estimated 80 cubic kilometers.

However, they also caution that ongoing declines in snowpack may hinder the aquifer’s long-term recharge. Further research is needed to fully map its size and determine how this water might be used.