WATER SECURITYWhere Did All the Water Go? New Study Explores Water Use in the Colorado River Basin.
The final 100 miles of the Colorado River is a shell of its former self — nearly 10 miles wide at the turn of the century, farmers had more water than they knew what to do with. Now, a weave of concrete canals brings water to sprawling industrial farms situated in the Mexicali Valley, with much of the natural riverbed dry and the wildlife sparse. Where did all the water go?
The final 100 miles of the Colorado River is a shell of its former self — nearly 10 miles wide at the turn of the century, steamboats would transport carriages and early-model cars from Mexicali to San Luis in Mexico’s Baja California state. Jaguars, beavers, deer and coyotes roamed the fertile riparian ecosystem and farmers had more water than they knew what to do with.
Now, a weave of concrete canals brings water to sprawling industrial farms situated in the Mexicali Valley, with much of the natural riverbed dry and the wildlife sparse. Tides still drive water from the Gulf of California into the valley a few times a year, but the days of a lush river delta in northern Mexico are long gone.
So, where did all the water go? Researchers on Thursday published one of the more comprehensive analyses of the Colorado River basin attempting to answer the question.
“What we’ve never had is a complete, holistic picture of where all of the Colorado River water goes,” said Brian Richter, president of Sustainable Waters and a lead author of the study.
Richter said that includes an accounting of how all the water in Mexico is used, water that’s exported out of the basin and water from the Gila River, a major tributary of the Colorado River that flows through parts of New Mexico and Arizona.
The answer will likely come as no surprise. According to the study, published in Communications Earth & Environment, irrigated agriculture is responsible for 52% of overall consumption in the basin, and 74% of direct human consumption.
Of that 52%, crops grown to feed cattle, such as alfalfa, account for 32% of all water consumed from the Colorado River.
In the upper basin, which consists of Colorado, Wyoming, Utah and New Mexico, the study found crops grown to feed cattle use 90% of all water diverted toward irrigation — that’s three times the amount of water used for municipal, commercial or industrial use combined.
Richter’s team of researchers calculated the water budget for specific crops by using satellite imagery of agricultural land, then factoring in things like climate and length of growing season to determine consumption.
“If somebody is going to make a statement about how much of the Colorado River goes to irrigated farms, we wanted to make sure they have the right statistics,” Richter said.