The leaning tower of San Francisco is not the only part of California that is sinking. More than 7 million acres (28,000 km2) of the Central valley are irrigated via an extensive system of reservoirs and canals. After a five-year drought, the reservoirs are drying up. The farmers in the central valley, the bread basket of the world, have also been using more underground water to irrigate their crops. Because of the marked increase in the use of the subterranean well water, the central valley has sunk up to 13 inches in some places. This is most apparent in bridge abutments over rivers and creeks.
California’s Central Valley is a large, flat valley that dominates the geographical center of the State of California. It is 40 to 60 miles (60 to 100 km) wide and stretches approximately 450 miles (720 km) from north-northwest to south-southeast, inland from and parallel to the Pacific Ocean coast.
The Central Valley is one of the world’s most productive agricultural regions.  More than 230 crops are grown there.  On less than 1 percent of the total farmland in the United States, the Central Valley produces 8 percent of the nation’s agricultural output by value: $43.5 billion USD in 2013.  Its agricultural productivity relies on irrigation from both surface water diversions and groundwater pumping from wells. About one-sixth of the irrigated land in the U.S. is in the Central Valley. 
Virtually all non-tropical crops are grown in the Central Valley, which is the primary source for a number of food products throughout the United States, including tomatoes, almonds, grapes, cotton, apricots, and asparagus. 
All these products are in serious jeopardy as farmers are being restricted in the amount of irrigation water available.
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