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- Title
Aquifer Stress History Contributes to Historic Shift in Subsidence in the San Joaquin Valley, California.
- Authors
Smith, Ryan
- Abstract
The San Joaquin Valley, California has experienced dramatic subsidence over the past 100 years, but the regions with the most subsidence have shifted dramatically over this time period, from west (Kettleman City/Los Banos) to south (Tulare/Pixley/Corcoran). To date, no study has done an in‐depth analysis of the mechanisms driving this shift in subsidence. We analyze head records, utilizing a novel approach that assimilates change in head data from multiple overlapping time periods, to produce an 80‐year record of change in head over both the historical and modern regions of greatest subsidence. We then calibrate a deformation model to fit both historical (measured with leveling surveys) and modern (measured with Interferometric Synthetic Aperture Radar, or InSAR) data sets. We find that the stress history of the Kettleman City/Los Banos region with historically high subsidence plays a large role in reducing modern subsidence in that region, while declining heads in both regions are likely to result in major subsidence over the next several decades. This study highlights the need for active groundwater management to mitigate ongoing and future subsidence. One key data set needed in this effort is accurate long‐term head histories to reconstruct the stress history of aquifers for accurate deformation modeling. Plain Language Summary: The San Joaquin Valley, California has experienced dramatic subsidence over the past 100 years, but the regions with the most subsidence have shifted, from west (Kettleman City/Los Banos) to south (Tulare/Pixley/Corcoran). In this study, we produce a model that reproduces the main subsidence patterns in each area. The model demonstrates that historical pumping in the western region, which caused extensive historical subsidence, made this region less susceptible to subsidence during the recent droughts, due to "stress memory" of the aquifer. When the aquifer experiences a level of stress that is lower than the highest stress it has previously experienced, subsidence is minimal. However, we find that if groundwater depletion continues, subsidence in both regions will likely be substantial, as both regions will experience groundwater stress beyond their historically highest levels. Key Points: Subsiding regions in the San Joaquin Valley, California have shifted dramatically from the 20th to 21st centuriesThe change in subsiding regions is driven primarily by stress history, and recent declines in pore pressureHistorical regions of high subsidence in the western San Joaquin Valley are likely to be "re‐activated" if groundwater level declines continue at recent (past 30 year) rates
- Subjects
LAND subsidence; DROUGHT management; AQUIFERS; SYNTHETIC aperture radar; GROUNDWATER management; WATER table
- Publication
Water Resources Research, 2023, Vol 59, Issue 11, p1
- ISSN
0043-1397
- Publication type
Article
- DOI
10.1029/2023WR035804