Fact Brief: Did groundwater pumping in the 20th century cause land to sink in Santa Clara County?

Yes.

According to the Oakland Museum of California, Santa Clara County used to sit 13 feet higher in 1854. Groundwater in the county was so abundant and the water pressure so significant that drilling ground wells would cause water to rush to the surface. 

By the 1920s and 1930s, the county was an agricultural powerhouse and groundwater was constantly tapped for vegetable and fruit production and hydrating its growing population. But heavy ground water usage caused parts of the county to sink, which created flooding hazards that ultimately led to the development of canals, dams and aqueducts to supply the area with water. 

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Sources

• Oakland museum of California Santa Clara Valley Land Subsidence
• USGS Land Subsidence in the Santa Clara Valley