The Hydrology of Mediterranean Mountain Areas

Abstract

AbstractThe study of the hydrology of Mediterranean mountain areas is especially important, as Mediterranean regions are characterized by unevenly distributed water resources that mainly depend on runoff generated in mountain areas. The objective of this article is to review some characteristic features of the hydrology of Mediterranean mountain areas, mainly based on results from small research catchments (less than 10 km2) mostly in Europe and in the United States of America. In addition, data obtained over the last 20 years from the Vallcebre research catchments (Eastern Pyrenees, Spain) are used to illustrate some of the characteristic features. Investigations show that the seasonal temperature evolution in Mediterranean regions has a direct effect on evapotranspiration dynamics, which, in combination with the seasonal dynamics of rainfall, cause the succession of wet and dry or very dry periods during the year. This seasonality of the Mediterranean mountain climate has a strong influence on the spatio‐temporal dynamics of both soil moisture and the water table. The succession of dry and wet periods and the characteristic occurrence of wetting‐up transitions between the two increase the complexity of the rainfall–runoff relationship in Mediterranean mountain areas by triggering a different combination of hydrological processes that depend on catchment wetness conditions. Research that is more process‐orientated is needed, using complementary approaches to further update a perceptual model of the hydrological functioning of Mediterranean mountain catchments. Its objective should be to work out more flexible process‐based modeling structures, which include the strong seasonality of Mediterranean catchments’ hydrology.