Decadal‐Scale Aquifer Dynamics and Structural Complexities at a Municipal Wellfield Revealed by 25 Years of InSAR and Recent Groundwater Temperature Observations. Issue 12 (12th December 2019)

• Record Type: Journal Article
• Authors: Grapenthin, Ronni; Kelley, Shari; Person, Mark; Folsom, Matthew
• Is Part Of: Water resources research. Volume 55:Issue 12(2019)
• Page Start: 10636
• Page End: 10656
• Publication Date: 2019-12-12
• Subjects: Aquifer dynamics -- InSAR -- groundwater modeling -- groundwater temperatures -- surface deformation; Hydrology -- Periodicals; 333.91
• DOI: 10.1029/2018WR022552
• Languages: English
• ISSNs: 0043-1397

Abstract

Abstract: Over the past 35 years the Buckman wellfield near Santa Fe, New Mexico, experienced production well drawdowns in excess of 180 m, resulting in ground subsidence and surface cracks. Increased reliance on surface water diversions since 2011 has reduced pumping and yielded water level recovery. To characterize the impact of wellfield management decisions on the aquifer system, we reconstruct the surface deformation history through the European Remote Sensing Satellite, Advanced Land Observing Satellite, and Sentinel‐1 Interferometric Synthetic Aperture Radar (InSAR) time series analysis during episodes of drawdown (1993–2000), recovery (2007–2010), and modern management (2015–2018) in discontinuous observations over a 25‐year period. The observed deformation generally reflects changes in hydraulic head. However, at times during the wellfield recovery, the deformation signal is complex, with patterns of uplift and subsidence suggesting a compartmentalized aquifer system. Recent records of locally high geothermal gradients and an overall warming of the system (~0.5°C during the water level recovery) obtained from repeat temperature measurements between 2013 and 2018 constrain a conceptual model of convective heat transfer that requires a vertical permeable zone near an observed fault. To reproduce observed temperature patterns at monitoring wells, high basal heat flow and convective cooling associated with downward flow of water from cool shallow aquifers during the drawdown period is necessary. The fault, however, appears to die out southward or may be locally permeable, as conceptual cross‐sectional hydrologic modeling reproduces the surface deformation without such a structure. Our work demonstrates the importance of incorporating well‐constrained stratigraphy and structure when modeling near‐surface deformation induced by, for instance, groundwater production. Key Points: Interferometric Synthetic Aperture Radar analysis spanning 25 years reveals complex surface deformation dynamics due to groundwater production and suggests permanent storage loss Locally high geothermal gradients and groundwater warming suggest groundwater upflow through a mapped, vertically permeable fault Conceptual cross‐sectional hydrologic modeling informed by Interferometric Synthetic Aperture Radar observations suggests a discontinuous or locally permeable fault/stratigraphic discontinuity