Mono Lake: The Underwater Towers Los Angeles Left High and Dry, California

On the eastern edge of the Sierra Nevada lies Mono Lake, an ancient salt lake with no outlet. Its water is nearly three times saltier than the ocean and highly alkaline. Along its shores stand strange knobby spires and columns of pale stone, some rising more than the height of a two-story house. These are tufa towers. Tufa forms underwater. Beneath the lake, calcium-rich fresh water from springs seeps up through cracks in the lakebed. When it meets the lake's carbonate-rich water, calcium carbonate, or limestone, forms and settles around the spring. Over long periods, it builds up into towers, often lined up along the faults that carry the spring water. As long as they stay submerged, the towers keep growing. For most of their history, the tufa towers along today's shore were hidden underwater. That changed because of Los Angeles, about 350 miles to the south. In 1941, the Los Angeles Department of Water and Power extended its aqueduct into the Mono Basin and began diverting four of the five streams that fed the lake, sending the water south to the growing city. With most of its inflow gone, Mono Lake began to shrink. By 1982, it had dropped 45 vertical feet and lost about half its volume, and its salinity had nearly doubled. The towers that had grown underwater emerged into open air. The falling lake also exposed a land bridge to Negit Island, letting coyotes reach a major California gull nesting colony, and it created dust storms from the exposed lakebed. In 1978, a group of young scientists and activists formed the Mono Lake Committee to save the lake. After a 16-year legal and political fight, in 1994, the California State Water Resources Control Board ordered Los Angeles to cut back its diversions until the lake rose to 6,392 feet above sea level. The lake has risen since, but drought and continued diversions have kept it below that target. Today, the exposed tufa towers have become one of California's most photographed landscapes. If the lake ever reaches its goal, some of them may disappear under the water again.