Hydrological Impacts of Climate Change: A Case Study on the Ebro River Basin (Spain). 2009

* Zambrano-Bigiarini M., Universita' degli Studi di Trento, Department of Civil and Environmental Engineering, Trento, Italy

Bellin A., Universita' degli Studi di Trento, Department of Civil and Environmental Engineering, Trento, Italy

Majone B., Universita' degli Studi di Trento, Department of Civil and Environmental Engineering, Trento, Italy

Bovolo, C I (Isabella.Bovolo@ncl.ac.uk) , Newcastle University, School of Civil Engineering and Geosciences, Newcastle upon Tyne, NE1 7RU United Kingdom

Blenkinsop S., Newcastle University, School of Civil Engineering and Geosciences, Newcastle upon Tyne, NE1 7RU United Kingdom

Uncertainty in projections from climate models limits the understanding of future hydrological impacts and complicates the assessment of mitigation policies. This work presents hydrological simulations of the Ebro River Basin (Spain), using both control (1961-1990) and future (2071- 2100) climate scenarios, in order to investigate the effect of climate change on the water availability of the basin. Using the SWAT model, hydrological simulations were carried out for four catchments with different climatological regimes. Sets of model parameters were identified using sensitivity analysis, long-term calibration and uncertainty analysis procedures, which enabled the historical behaviour of the catchments to be reproduced. Following validation, the parameters were used to simulate the effects of climate change on future streamflow. Bias-corrected daily time series of precipitation and mean temperature from an ensemble of 6 Regional Climate Models (RCMs), using the SRES A2 emissions scenario, were used as drivers of the hydrological simulations during the future scenarios. Important annual and seasonal differences in the projected future precipitation and temperature fields were observed among the RCMs. However, a general decrease in annual mean precipitation and an increase in annual mean temperature relative to the control period were observed, with the strongest differences during the summer season. When these changes were used to project future streamflows, a general decrease was observed at the outlet of the catchments. Changes in streamflows were in general agreement with the projections of daily precipitation and temperature fields, with a larger drop in predicted monthly streamflows for catchments with more semi-arid climatological regimes, and seasonal differences that are related to the elevation range of the catchments.