Evaluación y modelización con SIG del efecto del manejo del suelo y planta sobre la generación de escorrentía, pérdida de suelo y conectividad hidrológica en la cuenca del rio Vero (Huesca, NE España)

To develop hydrological response plans at catchment scale in Mediterranean agro-ecosystems, both in frequent and unfavourable scenarios, it is required to understand the behaviour of the different hydrological processes of runoff generation and pathways and soil erosion. For a better understanding of the dynamics of these processes, it is necessary to know the current agricultural practices applied in cultivated soils, which are vulnerable to water erosion, to manage them efficiently and sustainably. One of the recommended practices is the use of plant covers in woody crops, because of the good results at different spatio-temporal scales on the hydrological response of the soil, and therefore for soil and water conservation, and sustainable long-term productivity. The Mediterranean agriculture of the different regions presents marked productive specializations, being the main crops cereals, olives, vineyards, almonds and citrus, depending on the different edapho-climatic conditions and the traditional crops at each region. In all of them, the availability of water is one of the main limiting factors for crop yield. Hence, it is recommended to use the most advanced technological methods, such as the use of prediction models, developed to obtain spatially distributed rates and a better understanding of the role played by the different factors. Hydrological and soil erosion models are useful tools to evaluate the impact of the different soil and vegetation management practices on the spatio-temporal dynamics of runoff, soil erosion and sediment delivery. In this Master's Thesis, one of the most well-known and accepted hydrological indexes has been applied, the Borselli’s connectivity index, as well as a new aggregated index of connectivity (AIC) that integrates a larger number of processes. Both indices successfully generated the maps of structural hydrological connectivity of the Vero River Basin (380 km2, province of Huesca, NE Spain). The new index has also made it possible to simulate functional connectivity for 96 months, and to evaluate the relative weight of the heterogeneities of the selected basin. The new index integrates detailed information on topography, land uses, rainfall erosivity, surface roughness and soil water retention capacity. These improvements have resulted in more realistic and representative maps of hydrological connectivity processes, both structural and functional. Spatial and temporal changes were evaluated in the different land uses and geomorphological features. The validation of the simulation was done by using the river flow at the Barbastro gauging station. Results suggested that different runoff and sediment responses took place during the different months of the year. The new index appears as a recommended an easy-to-run tool in a GIS environment to study spatio-temporal dynamics at catchment scale, as well as to evaluate potential scenarios of soil and plant management, as well as different climatic conditions. As soil erosion seriously affects vineyards, in this Master's Thesis the effect of two types of plant cover (spontaneous vegetation and cover crop of common sainfoin) on soil moisture and the influence of different physiographic conditions on runoff and sediment yields were evaluated in a rainfed vineyard (Fábregas Cellar; NE Spain) during 15 months. Soil moisture conditions in the vineyards’ rows were dry and stable, in the inter-row areas were wet although variable, and wet and very stable in the corridors. Soil moisture in the inter-row areas with common sainfoin was much higher than in the rows (62 per cent – 70 per cent) whereas this difference was lower with spontaneous vegetation (40 per cent). Two runoff and sediment traps (STs) were installed in two ephemeral gullies, and 26 time-integrated surveys (TIS) done. The rainfall threshold for runoff generation was 12 mm and the rainfall erosivity threshold was 5.2 MJ mm ha–1 h–1 TIS–1. The mean and maximum runoff yields were 9.8 and 30.7 l TIS–1 in ST2 and 13.5 and 30.2 l TIS–1 in ST3. The mean turbidity was 333 and 19 g l–1, and the maximum sediment yields were 41,260 and 2,778 g TIS–1 in ST2 and ST3, respectively. Changes in the canopy covers (grapevines and plant covers) and rainfall parameters explained the runoff and sediment dynamics. After the Master's Thesis defence, several scenarios of good agro-environmental practices in the Vero River basin will be evaluated, at the CNR-IRPI in Padua, Italy, within the framework of an Erasmus+ Traineeship granted to the student of this Master's Thesis. The software developed by the researchers of this centre will be used to evaluate the selected scenarios