Efecte del canvi climàtic a nivell estacional als recursos hídrics del sistema Ter-Llobregat-Besòs

Abstract

On the 21st century, the hydrological cycle will bring strong quantitative variations at the horizon. Therefore, these variations will affected by future forecasts in a seasonal level due to the climate change. Given the dependence on water supply in the Barcelona Metropolitan Area, in response to the global change in its Ter, Llobregat and Besós basins, this work has been carried out with the aim of seasonally estimating the real behaviour of the water balance, and to contribute to the sustainable development of its resources. To consider the effect of temperature on water in the horizons of 2021 and 2050, the water balance of several subbasins in the -Ter, Llobregat and Besós catchements- has been estimated at seasonal level. The current actual evapotranspiration (ETr) has been calculated using Zhang et al. (2001) equation, taking into account the type of vegetation cover and the values of seasonal precipitation (P) and potential evapotranspiration (ET0). Using the water balance of each sub-basin and the ETr values, the water balance for 2021 and 2050 is then recalculated. Finally, the current and future R / P ratios are calculated to estimate the availability of water resources. The results show significant reductions in the availability of water resources, especially by 2050, which are indicated by the R / P ratios. All three basins will be affected by a decrease in water resources, although the Ter basin has a smaller water deficit. With regard to the supply capacity of the Barcelona Metropolitan Area, the indicative values are those corresponding to the Pyrenees, where it is stated that the contributions to the reservoirs that regulate each basin will be less reduced in the Ter basin than in the Llobregat and Besós basins due to the effects of climate change. In summary, climate projections, trends in land use change, the estimation of the quantity and variability of available water resources over the next few years is one of the main management and planning challenges for both environmental and economic development. Therefore, appropriate solutions are required for water conservation and where sustainable use is promoted