The Colorado Salinity Control Act, Public Law 93-320, June 24, 1974, was enacted to enhance and protect the quality of water in the Colorado River. Title II of the Colorado Salinity Control Act authorized the investigation and implementation of control measures for selected salinity-control units, including the McElmo Creek basin in Montezuma County, southwestern Colorado (fig. 1) (Bureau of Reclamation, 2003). Salinity is a concern in the McElmo Creek region of the Upper Colorado River Basin.