Glen Canyon Dam A dam in Glen Canyon was studied as early as 1924, but these plans were initially dropped in favor of the Hoover Dam (completed in 1936) which was located in the Black Canyon. By the 1950s, due to rapid population growth in the seven U.S. and two Mexican states comprising the Colorado River Basin, the Bureau of Reclamation deemed the construction of additional reservoirs necessary. However, the USBR faced opposition when it proposed the Echo Park Dam in Utah's Dinosaur National Monument, which the nascent environmental movement saw as a legal threat to the status of protected lands. After a
Course of the Colorado River of this water is used for irrigation in the Mexicali Valley, one of Mexico's most fertile agricultural regions. Below the Morelos Dam the Colorado forms the international border for a short distance, between Baja California and Arizona, before reaching the Southern International Boundary at San Luis Rio Colorado, where it crosses entirely into Mexico. For the remainder of its course to the Gulf, the river forms the boundary between Baja California (west) and Sonora (east). "River", however, is a misnomer as the Colorado is dry or small stream most of the year, due to its flow being almost completely exhausted