Drought conditions that cause the San Joaquin Valley to sink to 50 cm

Continuous droughts are causing some areas in central California to drop to 50 cm per year, the Cornell researchers found.

California is sinking.

A new researcher discovered that continuous droughts are causing some areas in central California to drop to 50 cm per year.

Despite heavy Rainfall amounts higher than normal at the beginning of 2017, When the rain stopped, the drought conditions returned and the land continued to sink, the researchers say.

Continuous droughts are causing some areas in central California to drop to 50 cm per year, the Cornell researchers found.

Continuous droughts are causing some areas in central California to drop to 50 cm per year, the Cornell researchers found.

THE USE OF CALIFORNIA WATER

About 80 percent of California's groundwater use is agricultural.

In the agricultural region of the Tulare basin in central California, farmers have been extracting groundwater for more than a century, the researchers said.

The winter rains in the valley and the melting of the surrounding mountains replenish the groundwater annually to a certain extent, but the drought has dried up the valley since 2011.

"With the severe storms of early 2017, Californians were hopeful that the drought was over," said Kyle Murray, a Cornell doctoral candidate in the field of geophysics who worked on the new study in Science Advances.

"There was a pause in the sinking of the land in a large area, and even the lifting of the land in some areas.

"But at the beginning of the summer the sinking continued at a similar rate that we observed during the drought."

Murray and Rowena Lohman, Cornell associate professor of earth and atmosphere sciences, examined satellite images of the San Joaquin Valley.

This region, like many others in the western United States, faces a continuous extraction of groundwater, which occurs faster than it can be replenished.

About 80 percent of California's groundwater use is agricultural.

In the agricultural region of the Tulare basin in central California, farmers have been extracting groundwater for more than a century, the researchers said.

The winter rains in the valley and the melting of the surrounding mountains replenish the groundwater annually to a certain extent, but the drought has dried up the valley since 2011.

In the agricultural region of the Tulare basin in central California, farmers have been extracting groundwater for more than a century, the researchers said. In the photo, a Tulare lemon grove with ripe lemons on the tree, Sierra Nevada mountains in the distance

In the agricultural region of the Tulare basin in central California, farmers have been extracting groundwater for more than a century, the researchers said. In the photo, a Tulare lemon grove with ripe lemons on the tree, Sierra Nevada mountains in the distance

In the agricultural region of the Tulare basin in central California, farmers have been extracting groundwater for more than a century, the researchers said. In the photo, a Tulare lemon grove with ripe lemons on the tree, Sierra Nevada mountains in the distance

Between 1962 and 2011, previous studies had found that the average volume of groundwater depletion each year was at least half a cubic mile.

Using satellite measurements between 2012 and 2016, the depletion of groundwater volume in the Tulare basin was estimated at 10 cubic miles, which is comparable to five times the volume of Cayuga Lake water (in the Finger Lakes region of New York) in that period of time.

Fresno and Visalia border the Tulare basin to the north, with Bakersfield to the south.

About 250 agricultural products grow there with an estimated value of $ 17 billion annually, according to the United States Geological Survey.

The valley holds about 75 percent of irrigated agricultural land in California and supplies 8 percent of the agricultural production in the United States.

"The California water problem has been examined from different angles in recent decades, this is a piece of that," he said.

"In this investigation, we observed 50 centimeters of subsidence during the drought, and then there were heavy rains and snowfall for several months in the spring and the sinking slowed down," Lohman said.

Six months after the rain, in the summer of 2017, we observed that subsidence rates are approaching their previous levels. It was a business as always.

Watering feeds the fertile agricultural land of the San Joaquin Valley seen from the air with rugged brown hills in the background

Watering feeds the fertile agricultural land of the San Joaquin Valley seen from the air with rugged brown hills in the background

Watering feeds the fertile agricultural land of the San Joaquin Valley seen from the air with rugged brown hills in the background

As an engineering problem, sinking damages infrastructure, causes roads to break down and leads to sinkholes, costly problems to fix, Lohman said.

"One of the places where it really matters in California is the aqueduct system that brings water to the region.

"They are designed with great care to have the correct slope to carry a certain amount of water," he said.

"Now, one of the main aqueducts in that area is tilted and can not deliver so much water, it's been a great engineering nightmare."

"Eventually, the quality of the water and the cost of extracting it could reach the point where it is no longer available."

Funding for this research was provided by NASA.

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