In 2010, Texas researchers injected dyes into 6 caves to map the Edwards Aquifer; groundwater crossed faults at up to 5,300 metres per day, revealing rapid flow paths

In 2010, the Edwards Aquifer Authority conducted a series of tracer tests in northern Bexar County, injecting nontoxic fluorescent dyes into six caves and monitoring 32 public and private wells to trace groundwater flowpaths. The tests recorded apparent groundwater velocities of up to 5,300 metres per day in the Panther Springs Creek groundwater basin. What they found was startling. In some spots, groundwater raced through the underground limestone at up to 5,300 metres per day, crossing major geological faults along the way, results that reshaped how officials think about protecting a water source that millions of people rely on every single day.

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