Indications for Protacted Groundwater Depletion after Drought over the Central Valley of California

Document Type


Journal/Book Title/Conference

Journal of Hydrometeorology


American Meteorological Society

Publication Date



Ongoing (2014-2015) drought in the state of California has played a major 10 role in the depletion of groundwater. Within California’s Central Valley, home to one 11 of the world’s most productive agricultural regions, drought and increased 12 groundwater depletion occurs almost hand-in-hand but this relationship appears to 13 have changed over the last decade. Data derived from 497 wells have revealed a 14 continued depletion of groundwater lasting a full year after drought, a phenomenon 15 that was not observed in earlier records before the 21st century. Possible causes 16 include (a) lengthening of drought associated with amplification in the 4-6-year 17 drought frequency since the late 1990s, and (b) intensification of drought and 18 increased pumping that enhances depletion. Altogether, the implication is that 19 groundwater storage in the Central Valley will likely continue to diminish even 20 further in 2016, regardless of the drought status.