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Las Tablas de Daimiel National Park is one of Spain's most representative groundwater‐ dependent ecosystems. Under natural conditions, water inflows combined brackish surface water from River Gigüela with freshwater inputs from River Guadiana and the underlying aquifer. Since the mid‐1970s, aquifer overexploitation caused the desiccation of the wetlands and neighbouring springs. The National Park remained in precarious hydrological conditions for three decades, with the only exception of rapid floods due to extreme rainfall events and sporadic water transfers from other basins. In the late 2000s, a decrease in groundwater abstraction and an extraordinarily wet period reversed the trend. The aquifer experienced an unexpected recovery of groundwater levels (over 20 m in some areas), thus restoring groundwater discharge to springs and wetlands. The complex historical evolution of the water balance in this site has resulted in substantial changes in surface and groundwater quality. This becomes evident when comparing the pre‐1980 groundwater quality and the hydrochemical status in the wetland in two different periods, under “dry” and “wet” conditions. Although the system is close to full recovery from the groundwater‐level viewpoint, bouncing back in the major hydrochemical constituents has not yet been obtained. These still appear to evolve in response to the previous overexploitation state. Moreover, in some sectors, there are groundwater‐dependent ecosystems that remain different to those found in preoverexploitation times. The experience of Las Tablas de Damiel provides an observatory of long‐term changes in wetland water quality, demonstrating that the effects of aquifer overexploitation on aquatic ecosystems are more than a mere alteration of the water balance and that groundwater quality is the key to aquifer and aquatic ecosystem sustainability., Centro de Estudios y Experimentación de Obras Públicas, España, Instituto Geológico y Minero de España, España, Facultad de Ciencias Geológicas, Universidad Complutense de Madrid, España, UNESCO/UNITWIN Chair “Appropriate Technologies for Human Development", Universidad Complutense de Madrid, España

El control de los recursos hídricos fue un objetivo fundamental para la Monarquía Hispánica en La Mancha durante la Edad Moderna. La desecación en 1751 de la superficie encharcada que forma el actual Parque Nacional de Las Tablas de Daimiel, promovida por Fernando VI, es un buen ejemplo de dicho control. Este artículo analiza los principales factores que confluyeron en aquella decisión que supuso la primera gran obra hidráulica de la monarquía borbónica en la cuenca del Guadiana. Para ello se ha estudiado, principalmente, la evolución de los molinos harineros del entorno de Las Tablas de Daimiel durante la Edad Moderna, los conflictos ocasionados por el control del caudal y la climatología de la zona durante la época estudiada. La presión de los molineros sobre el río y el aumento de la aridez provocaron una creciente conflictividad que la monarquía intentó resolver con la desecación. Sin embargo, el principal objetivo fue satisfacer los intereses recaudatorios de la monarquía y los de una serie de ganaderos de la zona vinculados al rey, Museo Comarcal de Daimiel, Instituto Geológico y Minero de España, Universidad Complutense de Madrid, Centro de Estudios y Experimentación de Obras Públicas

Human settlements around the fluvial wetland of Las Tablas de Daimiel (central Spain) have been related to the water availability in this area for nearly 5500 years; however the relationship of the hydrology of the wetland to climate change remains uncertain. Whilst archaeological and pollen data provide contradictory arguments, statistical empirical mode decomposition of geochemical data from core S-1 reveals arid periods ca. 1.8 cal. ka BP, ca. 3.3 cal. ka BP and ca. 5.5 cal. ka BP between which periods both Bronze Age and Iberian-Roman settlements developed. These periods can be identified in other records of the Iberian Peninsula and around the western Mediterranean. Comparison of these records points to a complex spatial pattern that evolved in time and, despite a number of forcings (volcanism, solar activity, atmosphere-ocean interactions) being invoked to explain such periods, there is no clear mechanism to explain their spatial pattern and the changes that have taken place since 2.5 ka BP., Departamento de Estratigrafía, Universidad Complutense de Madrid, España, Instituto Geológico y Minero de España, España, Museo Comarcal de Daimiel, España, Centro de Estudios y Experimentación de Obras Públicas, España

Las Tablas de Daimiel National Park has experienced many hydrological and ecological modifications through out its history, both of natural as well as anthropogenic origin, which have affected its carbon storage capacity and carbon fluxes. The study of those variations has been carried out by the analysis of its sedimentary record (geochemistry and pollen) and historical data. The natural changes have a wider variation range than the anthropogenic ones, showrepetitive patterns and the system reacts readjusting the equilibrium among its components. Anthropogenic effects depend on the direct or indirect impact on the wetlands of change and its intensity. In addition, the anthropogenic impacts have the capacity of breaking the natural balance of the ecosystem and the internal interactions., Dirección de Geología y Geofísica, Instituto Geológico y Minero de España, España, Departamento de Estratigrafía, Universidad Complutense de Madrid, España, Earth Surface Processes, United States Geological Survey, Estados Unidos, Dirección de Recursos Minerales, Riesgos Geológicos y Geoambiente, Instituto Geológico y Minero de España, España, Departamento de Geología, Universidad de Alcalá de Henares, España