Remote Sensing of Ground Deformation for Monitoring Groundwater Management Practices: Application to the Santa Clara Valley During the 2012–2015 California Drought

Abstract

Groundwater management typically relies on water‐level data and spatially limited deformation measurements. While interferometric synthetic aperture radar has been used to study hydrological deformation, its limited temporal sampling can lead to biases in rapidly changing systems. Here we use 2011–2017 COSMO‐SkyMed data with revisit intervals as short as 1 day to study the response of the Santa Clara Valley (SCV) aquifer in California to the unprecedented 2012–2015 drought. Cross‐correlation and independent component analyses of deformation time series enable tracking water through the aquifer system. The aquifer properties are derived prior to and during the drought to assess the success of water‐resource management practices. Subsidence due to groundwater withdrawal dominates during 2011–2017, limited to the confined aquifer and west of the Silver Creek Fault, similar to predrought summer periods. Minimum water levels and elevations were reached in mid‐2014, but thanks to intensive groundwater management efforts the basin started to rebound in late 2014, during the deepening drought. By 2017, water levels were back to their predrought levels, while elevations had not yet fully rebounded due to the delayed poroelastic response of aquitards and their large elastic compressibility. As water levels did not reach a new lowstand, the drought led to only elastic and recoverable changes in the SCV. The SCV lost 0.09 km3 during the drought while seasonal variations amount to 0.02 km3. Analysis of surface loads due to water mass changes in the aquifer system suggests that groundwater drawdowns could influence the stress on nearby faults.

Tracking Groundwater Levels Using the Ambient Seismic Field

“…Compounding this is the role of climate change, which has lead to more frequent and pronounced dry and hot years, along with stronger extreme precipitation events in places like California (Dettinger et al, 2011;Swain et al, 2016;Teng & Branstator, 2017). Surface displacements measured by GPS provide high temporal but sparse spatial resolution of groundwater level changes (Bawden et al, 2001;Ji & Herring, 2012;King et al, 2007), while those measured by Interferometric Synthetic-Aperture Radar bring high spatial resolution but limited temporal resolution (Chaussard et al, 2017;Galloway & Hoffmann, 2007;King et al, 2007). Surface displacements measured by GPS provide high temporal but sparse spatial resolution of groundwater level changes (Bawden et al, 2001;Ji & Herring, 2012;King et al, 2007), while those measured by Interferometric Synthetic-Aperture Radar bring high spatial resolution but limited temporal resolution (Chaussard et al, 2017;Galloway & Hoffmann, 2007;King et al, 2007).…”

A New Method for Isolating Elastic From Inelastic Deformation in Aquifer Systems: Application to the San Joaquin Valley, CA

“…Deformation associated with solid earth processes (e.g., volcanoes and earthquakes) and compressible sediments (e.g., aquifer) has been precisely mapped with InSAR and used to reach a better understanding of the physical processes operating in the Earth (e.g., Bürgmann et al, ). In hydrology, InSAR has been used for land subsidence monitoring, characterization of aquifer system properties, and evaluation of management practices (Amelung et al, ; Bell et al, ; Chaussard et al, ; Chaussard, Burgmann, et al, ; Chaussard, Wdowinski, et al, ; Chaussard et al, ; Miller & Shirzaei, ; Motagh et al, ).…”

Combining InSAR and Hydraulic Head Measurements to Estimate Aquifer Parameters and Storage Variations of Confined Aquifer System in Cangzhou, North China Plain

“…Compared with conventional geodetic techniques such as Global Positioning System and leveling surveys, Interferometric Synthetic Aperture Radar (InSAR), especially multitemporal InSAR, can obtain land deformation time series over large areas at significantly improved spatial resolution and with reduced temporal interval (Bai et al, ; Hooper et al, ). The advantages of InSAR make it potentially suitable for groundwater studies, and it has been applied to map aquifer system compaction/land deformation (Galloway et al, ; Lu & Danskin, ; Schmidt & Bürgmann, ), estimate aquifer system properties (Bell et al, ; Hoffmann et al, ; Miller & Shirzaei, ), predict hydraulic heads (Chaussard et al, ; Chen et al, ; Reeves, Knight, Zebker, et al, ), assess GWS variations (Béjar‐Pizarro et al, ; Castellazzi et al, ; Chaussard et al, ; Miller et al, ; Smith et al, ), and constrain transient groundwater flow models (Calderhead et al, ; González & Fernández, ; Hoffmann et al, ).…”