This paper assesses the impacts of climate change on water resources in the Western Macedonia water district, located in northern Greece. Some critical water management issues, such as reservoir storage and water supply for agriculture and domestic use, are investigated. A conceptual water balance model was calibrated using monthly historical hydrometeorological data. The proposed model was applied in the entrance of the Polyfyto reservoir in order to estimate runoff values under a transient scenario (UKTR) referring to years 2032 and 2080. The results show that the mean annual runoff, mean winter runoff and summer runoff values, annual maximum and minimum values, as well as monthly maximum and minimum, would be reduced. By using this transient scenario, the risk associated with the water supply for power production, agriculture and domestic use has been evaluated under conditions of altered runoff. Increases of the risks associated with the annual quantities of water supply have been observed.
Keywords: climate change scenario, reservoir, risk, water balance, water supply