We collected data of reservoir area, capacity, age, and location from open databases: Infraestructura de Datos Espaciales de Andalucía (IDEAndalucia; http://www.ideandalucia.es/portal/web/ideandalucia/) and the Ministerio para la Transición Ecológica (https://www.embalses.net/). The reservoir capacity (m3) divided by its surface area (m2) will yield the mean depth (m).
We obtained the lithology and land-use maps using ArcGIS® 10.2 software (ESRI 2012) under the Universidad de Granada license. First, we delimited the watershed of each reservoir using the rivers and hydrographical demarcations, and, second, we calculated the area for each different type of lithology and land-use within watersheds. We used the databases: Infraestructura de Datos Espaciales (IDE) from the Ministerio de Agricultura, Pesca y Alimentación (MAPA; https://www.mapa.gob.es/es/cartografia-y-sig/ide/default.aspx); the Infraestructura de Datos Espaciales de Andalucía(IDEAndalucia; http://www.ideandalucia.es/portal/web/ideandalucia/); the Instituto Geológico y Minero de España (IGME; http://www.igme.es/default.asp); the Confederación Hidrográfica del Segura (CHSEGURA; https://www.chsegura.es/chs/); and The Junta de Comunidades de Castilla-La Mancha (IDE-JCCM; https://castillalamancha.maps.arcgis.com/home/index.html). We defined the next categories: water-covered area; carbonate-rich rocks; limestones, marls, and dolomites; gravels, conglomerates, sands and silts; and non-calcareous rocks. The soils with high capacity to solubilize dissolved inorganic carbon are carbonate-rich rocks and limestones, marls, and dolomites. In contrast, non-calcareous rocks include igneous rocks like basalt and metamorphic rocks like marble, schist, quartzite, phyllite, gneiss, and slate have less capacity to leach dissolved inorganic carbon. The land-use categories were: crops, forest, urban, treeless area, and water covered area. The forestry area includes trees, plantation trees, sparse trees, and dispersed trees.
