Browsing by Subject "Soil water content"

Now showing 1 - 3 of 3
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    Morfología Fluvial.-Hidrología de un ambiente Mediterráneo de montaña. Las cuencas de Vallcebre (Pirineo Oriental) I. 20 años de investigaciones hidrológicas
    Latron, J.; Llorens, P.; Soler, M.; Poyatos, R.; Rubio, C.; Muzylo, A.; Martínez-Carreras, N.; Delgado, J.; Regüés, D.; Catari, G.; Nord, G.; Gallart, F.; Universidad de Murcia
    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.
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    Morfología Fluvial.-Hidrología de un ambiente Mediterráneo de montaña. Las cuencas de Vallcebre (pirineo oriental) III. Vegetación y flujos de agua
    Llorens, P.; Poyatos, R.; Muzylo, A.; Rubio, C.M.; Latron, J.; Delgado, J.; Gallart, F.; Universidad de Murcia
    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.
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    Relaciones agua-suelo-vegetación.-Evaluation of two methods for measuring saturated hydraulic conductivity of soils under two vegetation covers
    Rubio, C.M.; Josa, R.; Poyatos, R.; Llorens, P.; Gallart, F.; Latron, J.; Ferrer, F.
    ABSTRACT The main goal of this work is to determine and to evaluate the saturated hydraulic conductivity for a silt loam soil in field and laboratory conditions. The experimental area was located in the Vallcebre research catchments, in headwaters of the Llobregat River (NE Spain). Hydraulic conductivity was measured in the field using the Guelph permeameter and field saturated hydraulic conductivity (Kfs) based on Elrick equation was calculated. The Guelph permeameter measures were made in two conditions (dry and wet) and in profiles below two vegetation covers (meadows and forest). To determine the saturated hydraulic conductivity at the laboratory (Ks) the constant head permeameter was used. The average Kfs values for the wet period was about 2 cm·h-1. During the dry period, both soil profiles presented higher values, about 7.5 cm·h-1. Under laboratory conditions, mean observed Ks values were between 12 and 25 cm·h-1. The relationship Kfs/Ks was of 0.1 cm·h-1 in wet conditions and about 0.4 cm·h-1 in dry conditions. The results indicated significant differences between both methods and between both seasons. Differences can be explained by the anisotropy of soils as a consequence of vegetation root system that promotes preferential flows paths.