Regions of the western United States may run out of water in the coming decades due to a combination of natural and human factors, warn experts in an updated report released Monday.
According to Brad Udall, a scientist at the Water Institute of Colorado State University (CSU), and Jonathan Overpeck of the University of Michigan, the flow of the Colorado River (the largest in the region) by 2050 will be 35% lower. to the average registered during the twentieth century.
Moreover, they said, the American West will see less rainfall and snowfall "due to certain effects of climate change." Specifically, the flow of the Colorado River decreases by 4% for each increase of one degree Fahrenheit (approximately half a degree Celsius) due to evaporation.
Udall and Overpeck published this report in June 2017, which they updated now with additional data (hydrological models and observations) that would confirm that the "mega-gills" in the western United States. in the 1950s they were due to lack of specific rains, while the current ones are due to climate change.
But there are other factors that aggravate the situation, such as the growth of the human population. For example, in 1950 Colorado had 1.8 million inhabitants, against the current 5.7 million and the 8.5 million estimated for 2050.
In addition, and for that reason, the industry of the agriculture also has grown, reason why the infrastructure to feed of water to that industry already is insufficient.
In fact, the largest reservoir in the country (Lake Mead, on the Colorado River between Nevada and Arizona) and the largest mountain tunnel to divert water for agriculture (Adams Tunnel, on the Big Thompson River, in Colorado) are both of the first half of the last century, 1931 and 1947, respectively.
In the case of Lake Mead, its volume is currently one third of what it was in 1983 and each year the difference between the entry and exit of water causes a drop of 4 meters in the level of that lake, which provides water about 25 million people.
And although evaporation has an effect on the loss of water, the other element that leads to this imbalance is the agreement between the United States and Mexico so that the latter country receives the water that corresponds to it from the Colorado River basin.
At the same time, according to the researchers, the different water districts in the southwestern United States "do not keep an adequate record of how much water they draw from the Colorado River or its reservoirs," even though on average 90% of the the region is used for agriculture and livestock.
(tagsToTranslate) Warn (t) USA (t) stay (t) next (t) decades