Original paper

Evaluation of soil water balance components under different land uses in a mediterranean mountain catchment (Catalan Pre-Pyrenees NE Spain)

Loaiza-Usuga, Juan; Carlos Poch, Rosa M.


A study was carried out at Ribera Salada Catchment (NE Spain), affected by the abandonment of agriculture since 1950s, to determine the components of water budget under different land uses. The predominant land use is forestry (oak and pine), from forest to subalpine and sub-Mediterranean vegetation. Agriculture produces potatoes, alfalfa and cereals with a low level of nitrogen fertilization and high mountain grasslands with low level technology and low trampling. Field monitoring consisted of precipitation and evapotranspiration (ET) measurements, surface water collection with runoff boxes, continuous soil water measurement with capacitance probes, throughfall pluviometers and stem flow rings. This study presents the results of applying a weekly water balance in six stations over two years (2004-2005). The balance was established in two steps. The water balance was measured at each station. We applied the TOPLATS model a fully process-based hydrologic model, simulating all processes related to the hydrologic cycle. In the application, a large number of meteorological inputs are needed, and a relatively large number of soil physical, topographic, and land cover parameters need to be determined. For this study, TOPLATS has been calibrated using soil moisture data from one year, while the model validation has been performed across multiple years. The proposed balance is an acceptable reproduction of the field water behaviour during this period. The methodology used is appropriate for understanding the behaviour of the study basin. The results obtained indicated that the model accurately predicted the water budget of the watersheds measured in both years.