Joseph Poland of the U.S. Geological Survey used a utility pole to document where a farmer would have been standing in 1925, 1955 and where Poland was then standing in 1977 after land in the San Joaquin Valley had sunk nearly 30 feet. Credit: U.S. Geological Survey
The sinking is starting to destroy bridges, crack irrigation canals and twist highways across the state, according to the U.S. Geological Survey.Cheap food, huh? One would think that after figuring this out before, folks might have been keeping an eye on this. One would be wrong.
Two bridges in Fresno County – an area that produces about 15 percent of the world’s almonds – have sunk so much that they are nearly underwater and will cost millions to rebuild. Nearby, an elementary school is slowly descending into a miles-long sinkhole that will make it susceptible to future flooding.
Private businesses are on the hook, too. One canal system is facing more than $60 million in repairs because one of its dams is sinking. And public and private water wells are being bent and disfigured like crumpled drinking straws as the earth collapses around them – costing $500,000 or more to replace.
The sinking has a technical name: subsidence. It occurs when aquifers are drained of water and the land collapses down where the water used to be.
The last comprehensive survey of sinking was in the 1970s, and a publicly funded monitoring system fell into disrepair the following decade. Even the government’s scientists are in the dark...
Sneed and her boss at the U.S. Geological Survey, Claudia Faunt, have tried reaching out to various government agencies and private businesses to warn them and inquire about the extent of damage being done to infrastructure.
“We tried calling the railroads to ask them about it,” Faunt said. “But they didn’t know about subsidence. They told us they just fixed the railroads and categorized it as repair.”
Thousands of miles of highways snaking through the state also are being damaged, she said.
“They go to repair the roads, but they don’t even know it’s subsidence that is causing all the problems,” Faunt said. “They are having to fix a lot because of groundwater depletion.”
A spokeswoman for the state Department of Transportation said the agency does not track costs related to subsidence and was not aware of any current bridge repairs resulting from it.
But Faunt pointed to the Russell Avenue bridge that crosses the Outside Canal in the Central Valley. It sank during two previous droughts – one in the late 1970s and then again between 1987 and 1992. Now with the current sinking, the 60-year-old bridge is almost totally submerged by canal water.
Down the road about a mile, Russell Avenue crosses another irrigation canal, the Delta-Mendota Canal. That bridge is sinking, too, and now is partially submerged in water. Plans to replace it are estimated to cost $2.5 million, according to an estimate by the Central California Irrigation District.