Two recent developments give rise to optimism in the effort to improve water quality in the southwestern United States. Both the passage of the Colorado River Basin Salinity Control Act of 1974¹ and a proposal by the Environmental Protection Agency for the establishment of a salinity control program in that same basin² tackle what has sometimes been considered an insurmountable interstate and international problem.

The Colorado River is a major North American river with a watershed of over 244,000 square miles in the United States and the Republic of Mexico. Its 1,450-mile length drains parts of Arizona, Colorado, New Mexico, Utah, Wyoming, Nevada, California, and Mexico. Much of the river is an agricultural-use watercourse, but the Colorado also is a major source of water to satisfy the municipal and industrial needs of nearly 10 million people in the Los Angeles-San Diego metropolitan area. It has been said that the Colorado River "is undoubtedly the Pacific Southwest's most valuable material resource."³