The Effect of Climate Change on the Discharge and Characteristics of Karst Springs in Kermanshah Province

Mountainous regions of Folded Zagros (karst basin of Alvand) and High Zagros in Kermanshah have various karst aquifers which are discharged by karst springs. The aforesaid aquifers are considered as the main source providing drinking water of human communities, the ecosystems of the basins, and basic current of Alvand and Qaresou Rivers. Moreover, they have a vital role in the sustainability, continuity, and formation of urbanization in the studying area. The present study aims to investigate the effects of climatic changes on quantitative features and not only the present but the future discharge diet of the springs. In the present research, hydrodynamic method (Mangin method and time series) and hydro-chemical method (graphic method, ionic and saturation ratios) are used to evaluate karst system feature of the index aquifers. The findings show that karst geomorphology in High Zagros is more developed than the zone of Folded Zagros. Besides, the findings from hydrodynamic and hydro-chemical methods of the aquifers prove different development of karst systems and different hydrodynamic and hydro-chemical behavior of the aquifers. Comparing the findings from hydrodynamic and hydro-chemical methods and surface karst developments, it turns out that karst geomorphology has a firm effect on qualitative and quantitative features of the studying aquifers. Furthermore, studying the precipitation process of the region during the last decades reveals a decreasing process of precipitation and the occurrence of numerous droughts during last two decades leading to a decreasing process of discharge process of the springs. Predicting climatic changes of the regions in future indicates that there is a decreasing process of precipitation and changes affecting discharge diet of karst springs. Moreover, predicting annual discharge of the studying springs during next decade shows a considerable decrease of the spring discharge. The output of climatic models demonstrates that not only the discharge decrease, but also the periodic movement of over-hydration to cold season and the decrease of base discharge in hot period of year are regarded as the other climatic factors on the studying karst springs. Moreover, the difference of surface karst morphology and the rate of development of karst system lead to different hydrodynamic behavior of aquifers against precipitation fluctuations and climatic changes. Besides, qualitative features of the studying water have a significant relationship with the input water volume entering the aquifer and has no relationship with precipitation fluctuations.