Hydrological functioning of mediterranean mountain basins in Vallcebre, Catalonia: Some challenges for hydrological modelling

Abstract

The Vallcebre research catchments are located in the south-eastern Pyrenees, in an area of diverse land use and varying levels of degradation, including forested hillslopes, abandoned agricultural terraces and badland areas. Outside the badlands, the hydrological response is controlled by saturation mechanisms. Between September and June the spatial patterns of saturated areas and soil moisture are determined by subsurface¯ow, modi®ed by the premature saturation of the inner parts of agricultural terraces, and the negative soil moisture anomalies induced by forest patches overgrown in grassland areas. During summer, this behaviour ceases because of soil moisture depletion and badland surfaces are the only hydrologically active areas, producing excess runo in response to the intense rainstorms. During the beginning and the ending of the wet season, the saturation of active areas shows a hysteretic behaviour that breaks the linearity between the mean water reserve of the basin and the relative saturated area.

Water and sediment budgets unveiling contrasting hydro-sedimentary patterns in a mountainous Mediterranean catchment

“…>85 %) limits the amount of surface runoff. Other authors have reported similar responses in nearby catchments (Gallart et al, 1997;Lana-Renault et al, 2007 in the Pyrenean Vallcebre and Arnás basins, respectively). Further downstream (Inglabaga-Altés), the mainstream river transfers part of its flow into the aquifer in spring and especially in summer when the aquifer is at its lowest (see values for dry sub-catchment in Table 2); transmission losses give the summer the lowest WY (in Altés), while the lowest WY in Inglabaga is observed in Autumn (Table 2).…”

Factors and interactions controlling infiltration, runoff, and soil loss at the microscale in a patchy Mediterranean semiarid landscape

“…In several studies conducted in Mediterranean drylands, the mechanisms of runoff generation (infi ltration excess versus saturation excess) have been found to depend on control properties such as organic carbon, soil substrate or slope morphology (Gallart et al, 1994(Gallart et al, , 1997Martínez-Mena et al, 1998) and also on initial soil moisture (Calvo-Cases et al, 2003). In our study, the dominant runoff mechanism on bare soils seemed to depend on the antecedent moisture ( Figure 4) and soil depth.…”

The Hydrology of Mediterranean Mountain Areas

“…2008), the stormflow coefficient has a clear seasonal pattern with predominant alternation between a wet period (November to March), when the catchment is hydrologically responsive, and a dry period mainly in the summer, when the catchment is much less reactive to any rainfall input. This seasonality of the hydrological response is most likely to be related to the similar seasonal evolutions of soil moisture shown in Figure 4 and described by Gallart et al. (1997, 2002) and of water‐table levels, as shown in Figure 5.…”

“…In the Vallcebre catchments , the stormflow coefficient has a clear seasonal pattern with predominant alternation between a wet period (November to March), when the catchment is hydrologically responsive, and a dry period mainly in the summer, when the catchment is much less reactive to any rainfall input. This seasonality of the hydrological response is most likely to be related to the similar seasonal evolutions of soil moisture shown in Figure 4 and described by Gallart et al (1997Gallart et al ( , 2002 and of water-table levels, as shown in Figure 5. Finally, the relationship between the stormflow coefficient and other common hydrological variables (rainfall depth, rainfall maximum intensity, baseflow) shows that observed correlations in Mediterranean mountain catchments (Cosandey 1993 [France], Ceballos and Schnabel 1998 [Spain]; Latron et al 2008 [Vallcebre catchments, Spain]) are generally of the same kind as those observed for humid conditions, even if reported correlation coefficients are lower.…”