Characterization of land subsidence in Tabriz basin (NW Iran) using InSAR and watershed analyses

Abstract

Iran as a semi-arid and arid country has a serious water challenge in the recent decades. While water demand is increasing, as a consequence, land subsidence due to excessive water extraction is happening in major basins of the country. Recently the land subsidence has been proposed as an environmental problem in the country and thus important projects on this matter have been conducted. For example several basins in the country have been studied using SAR data and their result had a great deal on water management section. This paper studies the large-scale immature land subsidence in the Tabriz basin (NW Iran) using the permanent scatterer synthetic aperture radar interferometry technique with the small baseline InSAR approach and watershed analysis. InSAR time series analysis of 17 Envisat advanced SAR images between 2003 and 2010 reveals three oval-shaped regions of subsidence. The recognized water wells in the study area are categorized into two groups (sub-basin 1 and 2) based on watershed analysis in the TB and are compared with InSAR results. InSAR time series from Kriging interpolation method are also compared with GPS time series of permanent TABZ station which suggests that the land subsidence only is growing in the basin far away from the Tabriz city.