Confined aquifer head measurements and storage properties in the San Luis Valley, Colorado, from spaceborne InSAR observations

• Published in: Water resources research 2016-05, Vol.52 (5), p.3623-3636
• Main Authors: Chen, Jingyi, Knight, Rosemary, Zebker, Howard A., Schreüder, Willem A.
• Format: Article
• Language: English
• Subjects: Agricultural land; Aquifer storage; aquifer storage properties; Aquifers; Coefficients; Compaction; Confined aquifers; Data analysis; Data processing; Deformation; Detection; Estimates; Groundwater; Groundwater basins; Groundwater levels; Groundwater storage; hydraulic head; InSAR deformation map; Interferometric synthetic aperture radar; Interferometry; Locations (working); Piezometric head; Properties; Pumping; Radar; Records; Regions; Remote sensing; Resolution; SAR (radar); Sensing techniques; Spatial discrimination; Spatial resolution; Storage coefficient; Subsidence; Synthetic aperture radar; Temporal variations; Timing; Vegetation; Vegetation growth; Water; Well data
• ISSN: 0043-1397; 1944-7973
• DOI: 10.1002/2015WR018466

Interferometric Synthetic Aperture Radar (InSAR), a remote sensing technique for measuring centimeter‐level surface deformation, is used to estimate hydraulic head in the confined aquifer of the San Luis Valley (SLV), Colorado. Reconstructing head measurements from InSAR in agricultural regions can be difficult, as InSAR phase data are often decorrelated due to vegetation growth. Analysis of 17 L‐band ALOS PALSAR scenes, acquired between January 2007 and March 2011, demonstrates that comprehensive InSAR deformation measurements can be recovered over the vegetated groundwater basin with an improved processing strategy. Local skeletal storage coefficients and time delays between the head change and deformation are estimated through a joint InSAR‐well data analysis. InSAR subsidence estimates are transformed to head changes with finer temporal and spatial resolution than is possible using existing well records alone. Both InSAR and well data suggest that little long‐term water‐storage loss occurred in the SLV over the study period and that inelastic compaction was negligible. The seasonal head variations derived from InSAR are consistent with the existing well data at most locations where confined aquifer pumping activity dominates. Our results demonstrate the advantages of InSAR measurements for basin‐wide characterization of aquifer storage properties and groundwater levels over agricultural regions. Key Points: InSAR can be used to measure head levels and storage properties in confined aquifers The achieved temporal and spatial resolution is much finer than that of existing well data Persistent scatterer techniques can be employed to correct vegetation decorrelation artifacts