When the Colorado River and its tributaries flow through the Colorado Plateau, which is dominated by sedimentary rocks formed in a marine environment, the increased concentration of salt degrades the water quality of the river dramatically. Saline springs flow directly into the Roaring Fork, the Dolores, Cataract Canyon, and the Little Colorado River. The situation is compounded even further by all the reservoir evaporation in these desert climes, especially in Lake Powell and Lake Mead. By the time it gets to end-users like San Diego and Tucson, the water is typically blended with alternative water sources to lower the concentration of total dissolved solids.
The Colorado River Salinty Control Program
Paradox Valley Environmental Impact Study
Read the article about the EIS