About Region 7
The Region covers approximately 13,000,000 acres (20,000 square miles) in the southeastern portion of California. It includes all of Imperial County and portions of San Bernardino, Riverside, and San Diego Counties. It is bounded on the east by the Colorado River; to the south by the Republic of Mexico; the west by the Laguna, San Jacinto, and San Bernardino Mountains; and to the north by the New York, Providence, Granite, Old Dad, Bristol, Rodman, and Ord Mountain Ranges.
The Colorado River Basin Region is located in the most arid area of California. Despite the relatively dry climate, the Region contains some substantial surface water bodies, including the Colorado River and the Salton Sea. Many of the alluvial valleys in the Region are underlain by ground water aquifers that in many cases are the sole source of water for local areas. The most Regionally important ground water basin underlies the Coachella Valley.
Some of the primary challenges facing the Region include pollution from Mexico, increasing salinity, selenium, and eutrophication in the Salton Sea, silt, nutrient, and pesticide pollution of the agricultural drains in Imperial Valley and the New and Alamo Rivers, and underground leaking tanks. For more information, please click on the following: Region 7 Fact Sheet
In order to assist interested persons in determining if a project is located in the Colorado River Basin Region (Region 7), a list of cities is provided: Cities in the Colorado River Basin Region