Subsurface water flux in California’s Central Valley and its source watershed from space geodesy
Donald F. Argus, Hilary R. Martens, Adrian A. Borsa, Ellen Knappe, David N. Wiese, Sarfaraz Alam, Mackenzie Anderson, Ashlesha Khatiwada, Nicholas Lau, Athina Peidou, Matthew Swarr, Alissa M. White, Machiel S. Bos, Matthias Ellmer, Felix W. Landerer, W. Payton Gardiner | September 29th, 2022
We combine measurements from Global Positioning System positioning and Gravity Recovery and Climate Experiment gravity to infer change in water components in Central Valley and its source watershed, the Sacramento-San Joaquin-Tulare River basin better than possible with either technique separately. We find that the Central Valley has lost groundwater from 2006 to 2021 at 2.2 ± 0.7 km 3/ yr (95% confidence limits follow the “±” sign), with 2/3 of the groundwater loss occurring in the southern part of the Valley. We estimate the seasonal recharge and loss of subsurface water in the Central Valley. Comparison to a model accounting for precipitation, evapotranspiration, and river water entering and leaving the Central Valley suggests that deep groundwater may be flowing from the Sierra Nevada mountains into the Central Valley.
Keywords
Central Valley, Groundwater Exchange, groundwater recharge, monitoring