GIS-based models for water quantity and quality assessment in the Júcar River Basin, Spain, including climate change effects

Abstract

This paper describes two different GIS models - one stationary (GeoImpress) and the other non-stationary (Patrical) - that assess water quantity and quality in the Júcar River Basin District, a large river basin district (43,000km(2)) located in Spain. It aims to analyze the status of surface water (SW) and groundwater (GW) bodies in relation to the European Water Framework Directive (WFD) and to support measures to achieve the WFD objectives. The non-stationary model is used for quantitative analysis of water resources, including long-term water resource assessment; estimation of available GW resources; and evaluation of climate change impact on water resources. The main results obtained are the following: recent water resources have been reduced by approximately 18% compared to the reference period 1961-1990; the GW environmental volume required to accomplish the WFD objectives is approximately 30% of the GW annual resources; and the climate change impact on water resources for the short-term (2010-2040), based on a dynamic downscaling A1B scenario, implies a reduction in water resources by approximately 19% compared to 1990-2000 and a reduction of approximately 40-50% for the long-term (2070-2100), based on dynamic downscaling A2 and B2 scenarios. The model also assesses the impact of various fertilizer application scenarios on the status of future GW quality (nitrate) and if these future statuses will meet the WFD requirements. The stationary model generates data on the actual and future chemical status of SW bodies in the river basin according to the modeled scenarios and reflects the implementation of different types of measures to accomplish the Urban Waste Water Treatment Directive and the WFD. Finally, the selection and prioritization of additional measures to accomplish the WFD are based on cost-effectiveness analysis.