Cambios de usos del suelo y régimen hídrico en la rambla de Poyo y el barranc de Carraixet

Abstract

Research addresses a twofold dimension of land use and land cover dynamism. First the evolution and dynamics of land use changes in the second half of the 20th century is studied. Second modifications that may have been introduced in the soil/land cover water regime due two land use changes are also analysed. Three are the main objectives: (1) the development of a methodological framework for the analysis and modelling of land use changes, within the Geographical Information Systems (GIS) environment; (2) the establishment of a cycle of land use/land cover evolution (delimitation of the reference scenario, trends of changes and model characteristics), air photography to extract land cover information from 1945, 1956, 1978, 1991 and 1998 has been used, and (3) the study of the impact of land use changes in the water content of soils, actual evapotranspiration and water surplus. The research has been applied to three areas in the surroundings of the City of Valencia: a larger zone, understood as the reference spatial area of 1200 km2, and two small watersheds (used as contrasting zones within the general spatial picture). Results highlight great land use and cover transformations in less than 50 years, mainly produced by the expansion of cash crops (citrus) and urban development. The significance of such changes in the soil/land cover water regime is shown in the reduction of the water holding capacity, the decrease of actual evapotranspiration and the increment of water surplus.