The once inhospitable desert through which the Colorado River flows is now home to millions of residents and facilitates a significant amount of the nation's agriculture. Large housing tracts and golf courses and artificial recreation areas have appeared, and the desert now blooms with crops including cotton, alfalfa and other specialty food plants. With most of its water coming from Rocky Mountain snow melt, the Colorado River is expected to supply the water for these continually expanding communities, industries and commercial enterprises. According to the Sierra Club the Colorado River has become a plumbing system, and this has "wreaked havoc on the river and its riparian environment throughout the Colorado River Basin."
As of 2011, the Colorado River system is being used at a rate that is unsustainable for the future. While upper basin states are not currently using their full allotments of water, California is exceeding its share by more than 800,000 acre-feet, and the state is currently developing a plan to reduce its reliance on the Colorado River, according to the Sierra Club. Additional water is also being sought for the expanding areas of Las Vegas, Nevada and St. George, Utah. Those states that exceed their share, jeopardize sustainability for all the basin states.
The Sierra Club blames the massive demands on the Colorado River for the endangerment of the natural environment and wildlife. It states that most of the native fish are endangered, bird migratory stops have been severely truncated and degraded by transbasin diversions, and the region's spectacular scenery is becoming blighted. Native fish have been particularly affected since the ecosystem in which they evolved has been eradicated. Where the fish evolved in a river where drought was common and where the river had high peak flows and low late season flows, this has now been replaced by a controlled water system that must guarantee consistent water supplies for the urban areas, industry and agriculture. The Grand Canyon's ecosystem and natural geomorphic evolution is also threatened by the lack of seasonal peak flows and the lack of new silt, the main cause of which is the Glen Canyon Dam.
The massive extent of water diversion has caused increased salinity and selenium levels, and total maximum daily loads are in violation of the Clean Water Act. Selenium is a trace mineral that is incorporated into proteins to make important selenoprotein antioxidant enzymes. If a person ingests too much selenium they can develop selenosis and suffer gastrointestinal problems, hair loss, fatigue, mild nerve damage and irritability.
