The most critical impacts of climatic change on the Mediterranean society and environment are likely to be associated with water availability. The whole area is expected to become vulnerable to the scarcity and irregular availability of water resources. In the framework of the FP6 EU CIRCE project (http://www.circeproject.eu/), a Regional Assessment of Climate Change in the Mediterranean (RACCM) was produced in 2013 to support the design of adaptation and mitigation policies on the whole region including Europe, North Africa, and the Middle-East. To this end, a set of coupled models has been developed to produce regional climate change projections. These projections allow assessment of the response of the Mediterranean Sea to climate change over the period 1950-2050 under the A1B hypothesis and to a large extent, the associated uncertainty. Some results concerning the use of CIRCE scenarios for the assessment of impacts on water resources are presented with an emphasis on the methodological approach to bridge the scale gaps between climate model structure and the resolution of basin-scale hydrology. Focusing on Southern Italy, the sustainability of surface and groundwater resources is explored. Additional results concerning a coastal catchment in Lebanon are presented. In this case study regarding a snow-dominated hydrological system, the combined effect of changes in temperature and precipitation is highlighted. The above methodological approach set-up for the Mediterranean area could be adopted for regions in Southeast Asia where in order to undertake similar impact studies, the local scale of investigation plays a determinant role for water resources assessment and flood protection.