Análisis de los impactos del cambio de uso de suelo y el cambio climático sobre la disponibilidad del agua en la cuenca alta del río Paute

Abstract

Climate variations related to climate change (CC) and the dynamics of land cover/land use change (CCUS) can modify hydrological regimes and water availability. Both factors are present in the Paute river basin; hence, the importance of studying the individual and combined influence of these two factors. The present study analyzed water availability in the sub-basins of the Tomebamba, Yanuncay and Tarqui rivers that are part of the upper Paute river basin; for this purpose, a physical-based hydrological model (SWAT) was calibrated and validated for the period 2015 - 2021, for a subsequent projection until the mid-21st century, applying projections of scenarios RCP4. 5 and RCP8.5 scenarios obtained from 4 GCMs of the CMIP5 project database, and CCUS projections under a trend scenario, using a Weights of Evidence methodology, and Cellular Automata through EGO Dynamics. In the configuration of the hydrological model, 5 meteorological stations and 3 hydrological stations belonging to ETAPA were used, in which a quality control. The hydrological model was evaluated by applying precision statistics (NSE, R2, PBIAS and RSR), presenting satisfactory results and an adequate representation of the hydrology of the study area. The results of the CUSS projection showed a decrease in moorland and forest areas due to an increase in anthropic and agricultural areas focused on lower altitude areas close to population centers. On the other hand, the analysis of the CC projection showed an increase in precipitation intensities and temperature increases in all scenarios. Regarding water availability projections, the combined analysis of the CC and CCUS scenarios indicated an increase in the volume of water entering the hydrographic system and in water yield. Showing a greater influence to the CC than to the CCUS factor. The present investigation allowed us to evaluate the changes in water availability due to CC effects and CCUS dynamics. This knowledge could provide information to decision makers for the management of control, regulation and protection of water resources.