Capturing the flood in California’s ancient underground waterways
Called paleo valleys, these buried historic riverbeds are still the paths water wants to travel underground, like slow-motion rivers. Their extreme permeability means they can absorb about 60 times more water than the surrounding clay. Aquifers, which are better known, also hold water in coarse soils. But the paleo valleys born of the most recent glaciations are truly special, … They have super powers for moving water underground because they are exceptionally large, have unusually coarse gravel, and are relatively shallow—perhaps just a meter or two below the surface.
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