Hydro-economic analysis of the adaptation to climate change in the Jucar river system

The impact of climate change is nowadays becoming more and more evident. Climate warming is expected to considerably alter the water balance throughout Europe and to increase of about 20% water scarcity globally. There is the necessity to plan and manage water resources efficiently in the future and to evaluate climatic variability over the long term. Economic damages caused by climate change are ascertained. In the last two decades, the annual average economic consequences of droughts in Europe amounted to € 6.2 billion and the economic damage due to the summer drought of 2003 in Southern and Central Europe was more than € 8.7 billion [EEA, 2010]. This is only the beginning of the serious consequences caused by climate change. This project describes a method to analyze economic and hydrological impacts and adaptation to climate change in different uses system at basin scale. As case study is used the Jucar basin. The approach used in this project is called ‘Top-down’ [Wilby et al., 2009]. This method plans first the downscaling of regional circulation model output, using the statistical downscaling. The future climate datas are introduced in a rainfall- runoff model to obtain the different scenarios inputs. Then, the future water demands are estimated on the basis of the hydrological plan projections. The scenarios and the future demands are simulated using a DSS shell for developing water resources planning and management model, DSS Aquatool [Andreu et al., 1996]. The models is run for every proposed scenarios: short term (2006-2040), medium term (2041-2070) and long term (2071-2100). The results obtained with the model for the generated future scenario were used to study when urban and agricultural demands could be supplied. Using this results and the economic demand function, we have proceed to do a hydro-economic analysis. This evaluation is done using a hydro-economic model that represents regional scale hydrologic, engineering, environmental and economic aspects of water resources systems. The demand is related to a value economic concept and this permits to convert a complex multiobjective management problem into a simpler single-objective problem [Harou et al., 2009]. These are a usefull tools to compare and contrast results for the different climate scenarios. Results show that water uses in the basin are likely be negatively impacted by climate change. This effect is more severe under rcp 85 than under rcp 45. Reoptimization of the water allocation is not enough to compensate water scarcity, in fact demand guarantees decrease over the forecast period while, urban and agricultural deficits increase. This evolution causes critical and intense scarcity costs over all three term of simulation, confirming the drastic economical impact of climate change.