A dinosaur bone. The footprint of a woolly mammoth. An ancient shell imprinted on a rock in your backyard.
These are the images of the word “fossil” calls to mind. But, buried deep within the earth, there’s another kind of fossil you might not expect — ancient aquifers, created by rain and snow that fell more than 10,000 years ago. And unless the fossil water stores are better protected, scientists say, they may become a thing of the past.
New research on fossil water from Lawrence Livermore National Laboratory suggests that managers of drinking wells that pump fossil water can’t rely on it being replenished — especially during times of drought.
“It’s just like taking gold out of the ground, out of a mountain,” said Menso de Jong, the study’s lead author. “The gold is not going to grow back.”
The Lawrence Livermore study found clear evidence that 7% of the 2,330 California’s drinking wells tested are producing fossil water — and 22% of those wells are pumping mixed-age water containing at least some ancient water. That means that many Californians are already using fossil water to shower, flush their toilets and irrigate their lawns without knowing it.
Scientists say that further mapping out where fossil water is located and pinpointing the areas that depend on the ancient resource could help lead to better groundwater management and ensure that supplies are sustained to meet future needs.
If managers can determine how much fossil water is left, they can then ration it and work on strategies for replenishing the ancient wells.
Not all fossil water is “drinkable.” Some water is heavily contaminated due to its very nature. For example, much of the water that comes out of Bear and Cache creeks is considered “fossil” in that it is the water that once covered California millennia ago when the state was part of what we know as the Pacific Ocean.
That water is filled with brine and other types of sales. It’s one of the reasons the Yolo County streams are filled with boron, which whitens rocks and makes some of areas too harsh for plant life, fish or insects.
However, water from Cache Creek and Bear Creek aren’t used for the most part by humans. Rather the water is used by farmers through agreements with the Yolo County Flood Control and Water Conservation District.
But elsewhere, excessive agricultural and urban water use has depleted many of California’s aquifers, which serve as massive underground reservoirs. In some areas, the problem is so severe that the land is sinking — permanently in some cases.
California’s first-ever groundwater protection law, passed by the Legislature in 2014, requires local agencies to make…