Climate change has arrived in Germany and poses new challenges for water suppliers. WatDEMAND analyses what impact climate change will have on water demand in Germany and where new regions of water shortage might emerge.
WatDEMAND stands for Multi-sectoral Water Demand Scenarios for Germany and Estimation of Future Regions with Increasing Water Scarcity and is, like for example VERTIKAL and the soon to be launched ResilJetzt!, part of the DVGW research program "Zukunft Wasser".
In WatDEMAND, water demand in Germany is forecast until the end of the 21st century. For that, water demand is divided into the sectors households (IWW), industry (TZW) and agriculture (UHOH) to increase the detail of the results. For all sectors, the status quo is mapped first, before future scenarios are calculated using various methods. Depending on the sector, different data are available, which is why the methodology varies considerably:
- For municipal water demand, a broad data base exists and its influencing factors are well researched. The largest influence is population size, for which forecasts have been published, which served as one of the key factors in determining future municipal water demand.
- Industrial water demand, on the other hand, does not follow any clear patterns. Here, we therefore refer to existing forecasts for specific areas of industrial water demand, for example, for the development of cooling water demand. Combining various of such forecasts enables us to generate an approximate forecast for the course of the century.
- Agricultural water demand is particularly shaped by the irrigation needs of crops. UHOH has a model that it will use to calculate this for two exemplary crops. The result can be used to approximate the total agricultural water demand.
In the next step, potential future water shortage regions in Germany will be identified. For this purpose, the analysis results of the multisectoral water demand are intersected with the existing water supply. Data on water supply are taken from the climate impact study of the Helmholtz Centre for Environmental Research (UFZ), which was also published as part of the DVGW research program "Zukunft Wasser". This study analyses a large number of climate models and presents small-scale forecasts of the development of groundwater recharge, changes in river discharge and other climatic factors. From the intersection of future water supply and future water demand, potential water shortage regions can be identified.
The results of the research project will provide guidance to German water suppliers so they can prepare accordingly for risks associated with climate change and societal-technological change.