The Power of Silence

Early on a spring Sunday in 2014, the white light and arid breeze of the Sonoran Desert ushered in a refreshing morning. Farm workers labored in nearby fields, harvesting produce and moving irrigation pipes, their schedules dictated by moisture and sun. It was a typical day, but at 8:04 a.m., something atypical happened. A set of giant control wheels on the Morelos Dam, unmoved for decades, started screeching, cranking open the crimson steel gates of the last major blockade on the Colorado River. As the rusty doors lifted, a titanic surge of greenish-brown water raced south, swirling and eddying down a riverbed that had sat parched and unused since the late 1990s. Thirsty tamarisk bushes and cedar grass choked the way forward.

This blast of moisture was what’s called a pulse flow, designed by hydrologists to mimic a natural flood. The massive 105,392-acre-foot release was planned to last eight weeks, followed by smaller pulses over five years to support the rejuvenation of natural vegetation. It was