Morfología Fluvial.-Hidrología de un ambiente Mediterráneo de montaña. Las cuencas de Vallcebre (Pirineo Oriental) I. 20 años de investigaciones hidrológicas

Abstract

ABSTRACT The Vallcebre research catchments are located in a Mediterranean mountain area (Pyrenean range, NE Spain). These catchments were originally covered by Quercus pubescens Willd. and deforested for agricultural use in the past. Nowadays they are covered by mesophyle grasses with spontaneous afforestation by Pinus sylvestris L. In this context, different investigations studying water fluxes in the soil-vegetation-atmosphere continuum have been performed. The main objective of these studies is the analysis and modelling of the role of vegetation cover on the catchment water balance in a framework of climate and land use changes. The dynamics of rainfall interception and transpiration by Scots pines and pubescens oaks, are investigated in terms of their dependence on meteorological conditions, on soil moisture and water table depth. Furthermore, the role of vegetation on catchment water balance is analysed. The results underline: (i) the importance of rainfall interception losses by both tree species and the high temporal variability of this flux, (ii) the effect of forest covers on soil moisture and (iii) the differences in transpiration between species, showing Scots pines a strong reduction of transpiration during droughts. Modelling results indicate that TOPBAL model (a developed version of TOPMODEL for an improved simulation of the response of catchments with diverse vegetation covers and high climatic seasonality) improved the simulation of the catchment water balance.