Application of synthetic aperture radar interferometry (InSar) in defining groundwater-withdrawal-related subsidence, Diamond Valley, Nevada

Interferometric Synthetic Aperture Rader (InSAR) technique has been recently used in detecting and monitoring ground displacements such as volcanic activities, earthquakes, landslides and surface deformations caused by fluid extraction. Ground subsidence related to groundwater withdrawal has occurred in many places such as urban areas and large scale agricultural areas. This study utilizes interferometry to detect ground subsidence in an agricultural field, where a large volume of groundwater has been pumped for decades, in Diamond Valley, Nevada. InSAR has proven to have great potential to detect and quantify ground subsidence caused by aquifer system compaction. It mapped ground deformation signals with high spatial detail and resolution of displacement, developed in a groundwater basin in the area, using radar data collected from the ERS-1/ERS-2 and Envisat satellites. The subsidence signal at the south part of the valley, where irrigation wells exist, shows a minimum of 37.6 cm of cumulative subsidence between July 17, 1992 and November 27, 1999 and a 17.5 cm of cumulative subsidence between October 16, 2004 and December 15, 2007.The profile views of the subsidence signals assist in visualizing the deformation geometry which indicates that the subsurface lithology can increase or decrease the deformation. The subsurface model estimated from the history of water table decline and the subsurface lithology distribution approximately correlate with the subsidence signals. Poor correlation occurred where limited availability of good subsurface data and limited spatial coverage of well logs existed.