The spatial and temporal subsidence variability of the East Mesa Geothermal Field, California, USA, and its potential impact on the All American Canal System

The spatiotemporal variability of subsidence around the East Mesa Geothermal Field (EMGF) near the All American Canal (AAC) has been measured using 30 temporally averaged interferograms from 1992 to 2000. Deformation rate maps from two shorter time periods indicated the maximum subsidence rate of the EMGF was reduced from -43 mm year(-1) (1992-1997) to -34 mm year(-1) (1996-2000) corresponding to decreasing net geothermal water production. The maximum subsidence on the East Highline Canal was -9.5 +/- 0.5 and -2.4 +/- 0.8 cm for each shorter time period. Interferometric synthetic aperture radar (InSAR) stacking demonstrated its utility in monitoring subsidence of the canal caused by the nearby geothermal plant at regional coverage superior to ground levelling networks. Such data on the subsidence of surface and subsurface hydrodynamics along the US-Mexico border are scarce, and are particularly significant in a zone of present and likely future acute water resource management sensitivity.