Larry Stevens is an evolutionary biologist. For the last 41 years, he’s dedicated much of his life to the study and salvation of springs, little spots where water bubbles out of the earth.
Stevens stands in huge alcove carved out of a sandstone cliff on a remoter trail in Grand Canyon National Park. He holds a measuring cup under a stream of water that drips from a cluster of bright green ferns.
“Dripping Springs is a fairly small spring,” Stevens says. “We’re looking at half a gallon a minute of flow.”