Lake Tahoe's glistening blue waves, which straddles the California-Nevada border, come from a special mix of depth, purity, and low algae count. The adjacent granite watershed, which produces little silt, helps the lake's average clarity depth to be almost 70 feet. The remarkable cleanliness of the water lets sunlight reach far into the lake, producing a magnificent blue hue as light waves are scattered and absorbed at varied depths. The mountain environment and great height of the lake help to preserve its immaculate state. Urban growth and climate change have challenged the lake's clarity preservation goals of recent conservation initiatives. Estpected to be two million years old, the lake is among the oldest in North America and offers researchers rich geological and biological records. The lake's particular chemistry, depth, and elevation produce conditions that favor endemic species not found anywhere else in the globe.
