The spatial and temporal subsidence variability of the East Mesa Geothermal Field, California, USA, and its potential impact on the All American Canal System JOO-YUP HAN*†, R. R. FORSTER†, D. E. MOSER‡, A. L. J. FORD§, J. RAMI ´ REZ-HERNA ´ NDEZ¶ and K. F. TIAMPO‡ †Department of Geography, 260 South Central Campus Drive Room 270, University of Utah, Salt Lake City, UT 84112-9155, USA ‡Department of Earth Sciences, University of Western Ontario, London, Ontario, N6A 5B7, Canada §School of Conservation Sciences, Bournemouth University, Christchurch House, Talbot Campus, Poole, Dorset, BH12 5BB, UK ¶Engineering Institute, Universidad Auto ´ noma de Baja California-Mexicali, BC, Me ´xico (Received 30 October 2008; in final form 2 July 2009) 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 hydro- dynamics along the US–Mexico border are scarce, and are particularly significant in a zone of present and likely future acute water resource management sensitivity. 1. Introduction The East Mesa Geothermal Field (EMGF) is located about 25 km east of El Centro, CA, USA (figure 1), bounded by the All American Canal (AAC) System, the AAC to the south and the East Highline Canal (EHC) to the west. The AAC is a 132 km long irrigation conduit that moves 3800 hm 3 year -1 of water from the Colorado River at Imperial Dam westwards parallel and next to the US–Mexico border at a rate of 121 m 3 s -1 with a 53 m topographic difference (Roma ´n-Calleros and Ramı ´rez-Herna ´ndez 2003, Herrera-Barrientos et al. 2006, IID 2009). The EHC is one of the northerly trending branch canals of the AAC (Loeltz et al. 1975) and the upper reach of it is located adjacent to the EMGF. Ground displacements were expected to accompany large quantities of geothermal fluid extraction even before the construction of geother- mal fields in Imperial County, California, and ground subsidence monitoring networks *Corresponding author. Email: joo-yup.han@geog.utah.edu International Journal of Remote Sensing ISSN 0143-1161 print/ISSN 1366-5901 online # 2011 Taylor & Francis http://www.tandf.co.uk/journals DOI: 10.1080/01431161003749444 International Journal of Remote Sensing Vol. 32, No. 12, 20 June 2011, 3427–3449