Imperial Valley - Geography

Geography

The Imperial Valley extends southward for 50 miles (80 km) from the southern end of the Salton Sea into Mexico. Part of a trough stretching from the Coachella Valley to the Gulf of California, it is almost entirely below sea level—235 feet (72 m) below at the edge of the Salton Sea. Its hot desert climate is characterized by daily temperature extremes. It was once part of the Gulf of California, from which it was cut off by the dam-like deposits of the Colorado River Delta Fan as it carved out the Grand Canyon. Bordered by sand dunes and barren mountains, it was uninhabited until 1901, when the Imperial Canal was opened and diverted Colorado River water into the valley through Mexico. Flood-waters in 1905–07 destroyed the irrigation channels and created the Salton Sea now filled by the New River and irrigation run-off. The rivers in the southern part of the Salton Sea river basin flow south to north.

The valley is bordered by the Colorado River to the east and, in part, the Salton Sea to the west. Farther west lies the border with San Diego County, and to the south the international boundary between the U.S. state of California and Baja California, Mexico. To the north is the boundary with the Inland Empire's Riverside County and its Coachella Valley, which with the Imperial Valley form the "Cahuilla Basin" or the "Salton Trough".