The effects of climate change on the quality of raw water resources are investigated. In addition to the vulnerabilities of the various water resources, recommendations for action and adaptation strategies are identified.
Climate change is causing meteorological changes, such as increased dry spells, heavy rainfall events, and temperature increases. These changes can affect not only the available water quantity but also the microbiological and physico-chemical quality of raw water resources. These effects of climate change on water quality (e.g., dissolution of iron and manganese, mass proliferation of coli bacteria in lakes and reservoirs, development of algal blooms in surface waters) are investigated during the KLIWAQ project. First, a literature review is conducted to systematically compile and evaluate the current state of knowledge based on previously published data. In addition, the practical experience of water supply companies is collected in a survey in order to draw on current and practical empirical data. In a subsequent workshop with representatives of water supply companies, the results are discussed in depth and prioritized. In doing so, current as well as expected future challenges are worked out and measures which have already been taken are identified. The analysis distinguishes between different types of raw water resources (crevice groundwater, pore groundwater, bank filtrate, surface water) as well as different geosystem conditions and time scales. Finally, based on the obtained results, the research needs are defined and recommendations for action and an adaptation strategy are developed to ensure a high quality of raw water resources in the future.