The Ojos del Guadiana and del Gigüela springs: the recovery of a groundwater body declared “at risk”

Abstract

The "Ojos del Guadiana" and the "Ojos del Gigüela" are a set of springs that provide groundwater to the respective channels under natural conditions. The first are the source of the Guadiana river, whilst the second ones are located in the final stretch of the river. From the 1980s the intense exploitation of Aquifer System 23 generated a decrease in the groundwater level, which in turn caused these springs to dry up. After the wet period of 2009-2013 there was a slow recovery of the aquifers in the Upper Guadiana, reflected in a rise in the levels, which continued throughout 2014-2015, this then changed to register a new period of piezometric decline. The "Ojos del Guadiana" reappeared in January 2012 during the period of recovery of the aquifer, whilst water in the "Ojos del Gigüela" appeared four years later, in December 2015, after two dry hydrological years and the beginning of a period of piezometric decline. Hydrogeological developments in the period of December 2009 to February 2016 resulted in the recovery process of the aquifers in the Mancha Plain due to this wet period. The time lag in the presence of water in the two sets of springs is related to the geological and hydrogeological characteristics of calcareous Pliocene aquifer, specifically with its morphology in the western sector. The piezometric evolution of the Mancha Plain in the last 7 years describes the process of partial recovery of the Upper Guadiana Central Sector, from its deepest to its shallowest levels in the sense of the direction of the natural progression of the groundwater from east to west.