Scientists discover huge reservoir beneath Cascades, tripling Lake Mead

Researchers have discovered a massive water reservoir beneath the Cascade Mountain Range. It’s estimated to be three times the volume of the largest reservoir in the United States.

Scientists at the University of Oregon and Oregon State University, along with the U.S. Forest Service, found the hidden aquifer while looking at drill holes left behind by previous geothermal experiments and realized the rock was still wet further down than previously thought.

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How does the discovery compare to Lake Mead?

Researchers say the reservoir water totals are at least 81 cubic kilometers, tripling Lake Mead’s capacity.

“It is a continental-size lake stored in the rocks at the top of the mountains, like a big water tower,” earth scientist and the study’s co-author Leif Karlstrom said.

The Cascade Range extends for about 700 miles from northern California to British Columbia, and has been built up by volcanic activity over millions of years.

The high Cascades, within Oregon, where volcanic rocks date back 8 million years, have smooth slopes and ongoing volcanic activity. Meanwhile, the older Western Cascades that date to 45 million years ago, are filled with canyons and valleys carved by flowing streams.

The researchers used the gradual shift between these two zones to study how volcanic processes have affected the region over time, with the reservoir discovery coming as a complete surprise.

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What does the discovery mean?

Researchers say the untapped source of water is a reason to celebrate, but caution that it’s fed by snow, and snowpack is expected to decline significantly in the Cascades in the coming decades.

“If we don’t have any snow, or if we have a run of bad winters where we don’t get any rain, what’s that going to mean?” USFS Geologist Gordon Grant said. “Those are the key questions we’re now having to focus on.”