The Colorado River Threats to river and delta: Water flow is decreasing. This water serves 30 million people in seven U. S. states and Mexico, with 70 percent of its water siphoned off to irrigate 3. 5 million acres of cropland. Possible actions between the United States and Mexico could significantly reduce the flow of water into the delta, increase its salinity, and alter the natural vegetation. Drought has lowered water levels in upstream reservoirs, eliminating the occasional floods the delta needs to maintain and extend the partial recovery of the 1980s and 1990s.
The drought has left the Southwest grasping for water. South of Yuma, where the river forms a 23-mile boundary between the United States and Mexico, the International Boundary and Water Commission is considering proposals to straighten the channel and plan for a flood flow of 140,000 cub feet per second. Digging a channel capable of containing that flood level would require removing cottonwoods, willows, and other vegetation from both sides of the river. If this happens, as much as 500 acres of vegetation might be lost. Digging the channels would destroy the richest natural area along the river.
The Mesa de Andrade Marshes is home to 75 species of birds, while also providing a lot of greenery amongst the Sonoran Desert. These marshes are not fed by Mexican water though. The water comes from leaking, unlined portions of the All- American Canal in the U. S. It carries Colorado River water from the Imperial Dam west to California’s Imperial and Coachella valleys. The lost water supports the marshes and Mexiali Valley farms. This will change to help California use water more efficiently. The effect would be as significant as drying up the Mesa de Andrade marshes.
Water is available, we Just have to find a way to get it to the delta. Environmental and human impacts: In the 1920’s, Western states began portioning out the water by building dams and diverting the flow to Los Angeles, San Diego, Phoenix, and other fast growing cities. Droughts have impacted the river immensely. Water has been running low for the past decade, and it is said some of the reservoirs fed by the river will never be full again. Climate change will decrease the river’s flow by 5 to 20 percent by 2053. People are limited to amount of water they can consume.
They can’t freely use it to wash their cars or water their yards whenever theyd like. Before the water diversion was controlled, Colorado often flooded when runoff from winter snows and spring rains turned the rived into a monster. The floods could be disastrous, but at the same time, they laid down new sandbars, created sloughs; in the delta, those floods brought fresh water, deposited sediments to replace those washed away, and delivered nutrients needed by plants. Now, virtually every drop of The Colorado is managed and counted. If drought continues, and water levels in
Lakes Mead and Powell continue to decline, the bureau might have to declare a shortage and reduce Arizona’s water supply. The bureau has denied states California and Nevada water when they requested a bigger allotment. Alternatives to restarting the Yuma plant are using the 5 million acre-feet of water rights owned by theyre planting crops in the wrong places because water is free. The bureau has an alternate idea to the Yuma plant; they are considering other sources of water that would achieve the same results. They would like to negotiate “forbearance” agreements to temporarily lease water from farmers.
However, forbearance could raise legal issues, if leased Arizona water is sent out of the state. Another idea is recovering ground water from around Yuma and increasing irrigation efficiencies. Even if the bureau decided to do one of these alternatives, the other factor is high cost. Situation between U. S. and Mexico: The Colorado River flows into a vast delta in Mexico and into the Gulf of California. Some of the water from the Colorado River serves the Mexican people. In the Andes Mountains, glaciers are melting so fast that people in Peru, Bolivia and Ecuador are expected to lose a major source of fresh ater by 2020.
When this happens will there be more sharing with other regions? Won’t the water supply run out quickly then too? We can’t live without water! In 1944, the U. S. promised Mexico 1. 5 million acre-feet annually plus 200,000 acre-feet during flood years. The Cienega de Santa Clara is a large lake and marshland, which lies near where the Colorado River flows into the Gulf of California. This lake provides habitat for endangered Yuma clapper rail, as well as other endangered species. This is the largest wetland in the delta, and it’s very important for birds and to maintain hese places.
To meet US treaty obligations to Mexico while the desalting plant was under construction, the Bureau of Reclamation built a canal to carry Wellton-Mohawk water past Yuma. The canal brings about 108,000 acre-feet of water a year to Mexico. This water is not counted against Mexico’s allotment because of where it is delivered and lack of agricultural or municipal benefit; it’s delivered to the Cienega de Santa Clara. The desalting plant only operated for six months because of floods on the Gilar River, which caused it to shut down. The Gila River, which Joins the Colorado Just orth of Yuma, damaged the canal leading to the plant.
It was not re-opened because the desalting plant cost $250 million to build and desalination proved too costly. Recently, Congress authorized the Bureau of Reclamation to consider restarting the Yuma plant. If this were to happen, the plant would send about 78,000 acre-feet of desalinated water a year at full operation to the Colorado and the remaining 30,000 acre-feet to brine water to the Cienega de Santa Clara. The Cienega would receive two-thirds less water and the salt content would be more than three times the current levels.