Water resources are an integral part of the global hydrologic cycle and are considered among the natural systems most vulnerable to climate change. Research indicates that severe problems related to water will affect the globe around 2030, which will further intensify to attain its peak by 2100 unless a different water management trajectory is strategically implemented. To conduct an accurate climate change impact assessment it is necessary to conduct parametric analysis for vulnerability to assess for each system by constructing a conceptual hydrogeological model that is then transferred to a mathematical model of overall water resources. We present here a case study outlining plausible impacts of climate change on water resources of Armenia, particularly on river ecosystems. Based on this initial study, we propose certain recommendations for the future to reduce, if not reverse in its entirety, the vulnerability trajectory. We further conclude that vulnerability assessment of water resources resulting from climate change, as proposed here, can be applied for different countries and will be of considerable interest worldwide.