With more agricultural over pumping of underground aquifers predicted in Arizona, man-made earth fissures and collapsing land levels could increase, residents and geologists worry. Photo courtesy of the Arizona Geological Survey
DENVER, April 30 (UPI) -- Arizona is adopting a new regional water-use plan, and residents and geologists fear it could lead to more man-made geological changes in the landscape, including land levels falling and giant fissures splitting the earth.
As part of the Colorado River Drought Contingency Plan, approved by Gov. Doug Ducey in 2019, Arizona must curtail river water use to keep levels at Nevada's Lake Mead from dropping to dangerous levels.
The water level at the lake, near Las Vegas, has been declining since 1983. The lake is now about 40 percent full at about 1,100 feet. If it drops to 1,075 feet, a shortage would be declared and mandatory water cuts would occur throughout the U.S. West.
Farmers, facing drought conditions, want to return to ground pumping of the state's already-low ancient underground aquifers. Elsewhere in the state, where water is not regulated, out-of-state agriculture operations have moved in to drain underground water supplies.
"Arizona's challenges to manage its groundwater have implications for all other water use across the West," said John Fleck, a professor of water resources at University of New Mexico.
Pumping since 1900
Arizona's farmers have been pumping groundwater out of aquifers since 1900, and over-pumping has caused the ground levels to fall in 3,400 square miles of the state, geological mapping shows. Large fissures, some miles long, have opened up where land has collapsed.
Earth fissures can open overnight, usually after monsoon season in June through September, said Chris Wanamaker, assistant engineer in Pinal County, where most of the state's fissures are found.
At first, a small crack in the earth appears where the ground-level has dropped due to over-pumping, Wanamaker said. "A heavy rain brings water runoff into the crack, which can cause the land to erode suddenly as it collapses into the void," he said.
"It's kind of Biblical, when you think about the earth opening up, like an apocalypse or something," said Joseph Cook, a research scientist and fissures expert at the Arizona Geological Survey at Tucson's University of Arizona.
For residents, the fissures cause heartache, flooding and damage.
Queen Creek resident Joan Etzenhouser has four fissures, including one under her house, on her 3-acre property about 30 miles southeast of Phoenix. After monsoon rainfalls, the fissures sometimes open into gaping trenches, 6 to 10 feet wide and 30 feet deep.
Broken water lines
The moving ground under her home has broken water lines twice and cracked tiles inside, Etzenhouser said. She's filled the gap under her home with cement slurry.
"It can't really be fixed because a fissure is impossible to fix," she said. "I like where I live, but nobody's going to buy it. It's a worthless house on a worthless piece of property."
The county now keeps maps of earth fissures, county engineer Wanamaker said. Officials recommend that developers not build within 50 feet of them.
In other parts of the state, free, unregulated underground water has lured large agricultural operations that drill deep wells and drain the aquifers, causing the land to collapse.
In Cochise County, southeast of Tucson, cattle operations and nut-tree farmers pump so much underground water that the land has deflated by more than 10 feet since 1969.
About 42 miles of fissures have opened up, damaging a natural gas pipeline, roads, and power lines over the past decade, according to the state's geologists.
"The domestic wells are drying up," Willcox Mayor Mike Walls told UPI. "It's horrible. The big boys come in here with a lot of money and keep going after the water deeper and deeper."
In La Paz County, in the western part of the state, severe floods in Wendon, Ariz., have been caused by land collapse from over-pumped aquifers.
Saudis grow alfalfa
Saudi Arabian growers of water-intensive alfalfa drilled deep wells and now export hay to Europe and the Middle East.
Shallow domestic wells for rural residents have run dry, Kingman, Ariz., Republican state Rep. Regina Cobb said.
"Whoever has the big straw is the one that is able to draw the water out," Cobb said.
Cobb and other lawmakers faced opposition when they tried to pass locally controlled water management laws.
What's worse, local residents and water experts worry that once Arizona's underground water is gone, it might never come back, and the land will continue to collapse.
When too much water is taken from aquifers, pressure compacts the space between grains of sand and gravel, said Brian Conway, geophysics surveying unit supervisor for the Arizona Department of Water Resources.
"If you put a straw in there and suck all the milk out, the Rice Krispies are going to come together and compact," Conway said. "That's what's happening in the subsurface. It's hard for that to ever hold water again."