Autor/a:
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Pulido-Bosch, Antonio; Delgado Marchal, José; Sola, Fernando; Vallejos, Angela; Vicente, Fernando; López Sánchez, Juan Manuel; Mallorquí Franquet, Jordi Joan
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Abstract:
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Ground subsidence of detrital deposits in the Almer´ıa basin (SE Spain) was studied using the remote sensing technique of
Differential Interferometry SAR (DInSAR). This basin is one of the most arid in Europe, receiving an average rainfall of
250 mm per year. Over the last 60 years the region has experienced an enormous agricultural and urban expansion, whose water
demand has been largely supplied from groundwater, leading to the current situation of overexploitation of water resources.
This paper outlines the likely relationship between groundwater abstraction and subsidence. To this end, 34 ERS and Envisat
images, taken between 2003 and 2009, were analysed to estimate ground surface deformations, and hence, compared with
water table variations measured in a number of piezometers in the basin. The analysis shows a clear parallelism between
the variations in piezometric level and deformation of the ground surface. In addition, the zones of greatest subsidence
coincide with those areas where groundwater abstractions are concentrated. Subsidence over the examined period varies from
10 to 30 mm, with extreme values as high as 50 mm, which translates to a rate of between 1Ð7 and 5 mm/year, reaching
maximum rates of 8 mm/year at some points. Given such subsidence rates, damage to urban infrastructures are, for the moment,
incipient. |