Water demand of blue-green infrastructure and their short and long-term impact on the drinking water supply

Due to the advancing climate change, climate change adaptation measures such as blue-green infrastructures (BGI) are becoming increasingly important in urban water management and urban planning. The microclimatic cooling effect of blue-green infrastructure in particular reduces heat islands and thus improves the quality of life in densely built-up areas. However, this natural cooling effect can only be achieved if sufficient water is available for the BGI. Particularly during long periods of drought and heat, it is therefore often necessary to irrigate the BGI, which is currently carried out primarily with drinking water in Austria. A more sustainable irrigation solution should therefore be introduced in order to guarantee a secure supply of drinking water, especially on peak days, and to increase efficiency in the use of drinking water. Alternative water resources, such as rainwater or treated wastewater and gray water, play a decisive role here. This research project deals with the sustainable water supply of BGI. An analysis is carried out at building, district and city level in which BGI are categorized and their water requirements are derived, which are necessary to achieve optimal ecosystem performance. This project also deals with alternative water resources. Alternative water resources are identified, the quantitative availability and qualitative requirements are determined and the necessary treatment measures are identified. A further step is the derivation of strategies for the implementation of alternative water resources and the cost-benefit analysis of the use of alternative water resources. The aim of this forecast is to show the long-term effects on the drinking water supply. To this end, the peak water demand and the number of peak demand days are taken into account. The aim of the project is to demonstrate the long-term drinking water savings through the use of alternative water resources for the irrigation of urban green spaces.