title: Groundwater depletion in the Middle East from GRACE with implications for transboundary water management in the Tigris-Euphrates-Western Iran region.
abstract: In this study, we use observations from the Gravity Recovery and Climate Experiment (GRACE) satellite mission to evaluate freshwater storage trends in the north-central Middle East, including portions of the Tigris and Euphrates River Basins and western Iran, from January 2003 to December 2009. GRACE data show an alarming rate of decrease in total water storage of approximately -27.2±0.6 mm yr-1equivalent water height, equal to a volume of 143.6 km3during the course of the study period. Additional remote-sensing information and output from land surface models were used to identify that groundwater losses are the major source of this trend. The approach used in this study provides an example of "best current capabilities" in regions like the Middle East, where data access can be severely limited. Results indicate that the region lost 17.3±2.1 mm yr-1equivalent water height of groundwater during the study period, or 91.3±10.9 km3in volume. Furthermore, results raise important issues regarding water use in transboundary river basins and aquifers, including the necessity of international water use treaties and resolving discrepancies in international water law, while amplifying the need for increased monitoring for core components of the water budget.
authors: Science, Technology and International Affairs Program, School of Foreign Service, Georgetown University Washington, District of Columbia, USA ; UC Center for Hydrologic Modeling, University of California Irvine, California, USA.
authors: Katalyn A
authors: KA
authors: Voss
authors: James S
authors: JS
authors: Famiglietti
authors: Minhui
authors: M
authors: Lo
authors: Caroline
authors: C
authors: Linage
authors: Matthew
authors: M
authors: Rodell
authors: Sean C
authors: SC
authors: Swenson
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