The project assessed the effects of drought and dryness in Germany on water availability, soil water balance, and groundwater and provided possible solutions and recommendations for action. Special attention was paid to competing water uses and to less common adaptation measures, such as the reuse of treated and processed wastewater in urban areas.
Of central interest was the extent to which several consecutive years with large-scale, regionally low precipitation, as in 2018 and 2019, influence water availability, the soil water balance, and groundwater in Germany. Here, it was necessary to close data gaps and to develop new representations.
Periods of drought and dryness are characterised by several conflicts of use, which have already occurred in a regionally differentiated manner or may occur in the future. Dealing with conflicts of use, requires a tried and tested set of instruments and, above all, supporting information for decision-making to reduce and resolve conflicts accordingly. In regions with low groundwater recharge and water availability, assessing possible effects on the public water supply is necessary.
Furthermore, possible competing water uses are to be analysed, described, and evaluated. Such conflicts of use are likely to arise, for example, due to increasing agricultural irrigation.
A catalogue of measures and supporting rules for decision-making were developed in order to avoid, reduce, and solve water use conflicts. This has created opportunities to proactively avoid conflicts of use.
Individual options for action were examined in detail and, if necessary, tested in case studies. This included analyses of water retention in the area and, in particular, the development of guard rails for the partial substitution of groundwater and drinking water for irrigation in urban areas with wastewater previously treated in sewage treatment plants and then processed further.