Hydrological response types for gypsiferous soils in a semi-arid region during nine years of continuous record

A 9-year rainfall, sediment yield and runoff generation record from four experimental plots has been studied. Plots are located in the central Ebro Basin over smooth hillslope developed over gypsum and marl Miocene deposits. The hydrological response of these areas is a function of soil properties, final infiltration capacity and permeability of soils and rainfall characteristics, such as intensity and amount. Results show that there are two types of hydrological response in these areas. First is Hortonian like, which takes place during wet periods and it is responsible for the main part of total sediment yield. Second is like saturation excess overland flow, and it appears after long period. The presence of either type is controlled by a double threshold, starting from when runoff is significant. Copyright (C) 2002 John Wiley Sons, Ltd.