Glen Canyon Dam has also impacted the Colorado River well downstream of the Grand Canyon. When the gates of the dam were closed in 1963, the resulting reductions in river flow effectively dried up the Colorado River Delta, the large estuary formed by the Colorado River at the Gulf of California (Sea of Cortez) in Mexico. Prior to the completion of Glen Canyon Dam, about reached the delta each year, despite heavy water use in California and Arizona. Because Glen Canyon Dam made possible an increased utilization of water from the Colorado River system, not enough water is left to flow to the delta in a normal year, and about of ecologically productive wetlands have disappeared. In 2014 an intentional "pulse flow" was released into the delta to restore some of these wetlands; however the viability of such flows have been controversial, considering the already high demand for Colorado River water.