Water resources in the semi-arid to arid areas of Central Asia are often limited by low precipitation, and hence vulnerable to impacts of global change, i.e. socio-economic development and climate change. Both, socio-economic development and climate change are very likely causing significant changes as water resources are affected by two main effects: Firstly, growing population and industrial activities in the region raise the pressure on water resources due to increasing water abstractions. Secondly, air temperature in the region has been rising in the past far above global average and it is expected to increase further, which will lead to changes in runoff generation and therefore water availability. Increasing temperature as well as increasing water abstractions will affect water quantity and consequently water quality as a result of higher pollution intake or reduction in dilution capacity. Thus, it is of crucial importance to analyse and assess the state of current and future water resources to implement sustainable water management as the above mentioned effects very likely causing significant changes of water resources. Within the last years, the number of scientific research studies using large-scale models to simulate water availability and water use has increased substantially. Several new datasets from earth observations and new or improved models have been published (Werth et al. 2009; Werth and Güntner 2010; van Beek et al. 2011). Nevertheless, those studies focussed on water quantity and did not take into account impacts on water quality induced by global change although changes in water quality affecting aquatic ecosystems and species. Furthermore, spatially explicit large-scale modelling studies have not been carried out for Mongolia and Central Asia to get a comprehensive overview and assessment. To address this research gap, the large-scale water resource modelling framework WaterGAP 3 was applied to Central Asia with a focus on Mongolia to simulate impacts on current and future water resources. WaterGAP 3 consists of hydrology, water use and water quality sub-models in order to simulate current and future water quantity and quality.

Water resources in the semi-arid to arid areas of Central Asia are often limited by low precipitation, and hence vulnerable to impacts of global change, i.e. socio-economic development and climate change. Both, socio-economic development and climate change are very likely causing significant changes as water resources are affected by two main effects: Firstly, growing population and industrial activities in the region raise the pressure on water resources due to increasing water abstractions. Secondly, air temperature in the region has been rising in the past far above global average and it is expected to increase further, which will lead to changes in runoff generation and therefore water availability. Increasing temperature as well as increasing water abstractions will affect water quantity and consequently water quality as a result of higher pollution intake or reduction in dilution capacity. Thus, it is of crucial importance to analyse and assess the state of current and future water resources to implement sustainable water management as the above mentioned effects very likely causing significant changes of water resources. Within the last years, the number of scientific research studies using large-scale models to simulate water availability and water use has increased substantially. Several new datasets from earth observations and new or improved models have been published (Werth et al. 2009; Werth and Güntner 2010; van Beek et al. 2011). Nevertheless, those studies focussed on water quantity and did not take into account impacts on water quality induced by global change although changes in water quality affecting aquatic ecosystems and species. Furthermore, spatially explicit large-scale modelling studies have not been carried out for Mongolia and Central Asia to get a comprehensive overview and assessment. To address this research gap, the large-scale water resource modelling framework WaterGAP 3 was applied to Central Asia with a focus on Mongolia to simulate impacts on current and future water resources. WaterGAP 3 consists of hydrology, water use and water quality sub-models in order to simulate current and future water quantity and quality.