A joint study by the NASA and the University of California shows that up to 75% of water has been lost from Colorado River Basin since 2004. This massive loss of groundwater poses great danger to water supply to most parts of western United States.
This is the first study to quantify the amount of water that have been lost for the last decade and find out the effects which this may have to the people of Western United States.
According to the United States Bureau of Reclamation, the basin has been hard hit by the extreme drought which has been experienced for the last 14 years. The drought that is currently experienced is the worst for the last century.
The team of investigators used data from NASA’s Gravity Recovery and Climate Experiment mission to do a track of the changes which have occurred in the mass of Colorado Basin as well as changes in the amount of underground and surface water.
Measurements for the last ten years show that there has been a loss of 53 million acres feet of fresh water. This is twice the volume of America’s largest water reservoir-Lake Mead.
“We are not at a position to know how much water we are left with, so we can’t be at a position to know when we will be running out,” said Stephanie Castle who works as a water resource specialist at the University of California.
“This is not a small amount of water to lose. We initially thought the picture could be really bad, but this was quite shocking”.
Surface water in the United States is managed by the United States Bureau of Reclamations and any loss that occurs is well documented.
However, there is no documentation on underground aquifers because this is just regulated by the respective states.
“The only way to study such a huge area is via satellite,” said Jay Famiglietti who works as senior water scientist at JPL. There is not enough data from well data to help put together a consistent picture basin wide,” he says.
Famiglietti asserts that the satellite project can be equated to having a massive scale in the sky. Scientists say that the change in mass of a place due to loss of water can influence the area’s gravitational attraction. By measuring gravity after some time, it’s possible to know how much an area or a region has lost.
Colorado River is the biggest in southwestern United States and its entire basin supplies more than forty million people scattered across seven states. It also irrigates more than four million acres of land.
“There is no doubt that the Colorado River Basin is the lifeblood of the western part of the US,” said Famiglietti.
“With Lake Mead at its lowest level ever, we wanted to investigate whether the basin was dependent on groundwater to take up the limited supply of surface water. We found out pretty high level of reliance of ground water to fill the gap between demand and supply”.