Urban water systems are characterised by tight linkages between
- natural aquatic ecosystems which have been severely modified in terms of their morphology, fluxes of water and matter, and aquatic communities,
- large-scale technical systems of water capture, treatment, storage and distribution forpotable consumption, wastewater and runoff collection, purification and subsequent discharge to receiving water bodies, and
- multiple uses such as waterways and recreation.
This creates multiple interfaces which are
often unique for urban water systems. Examples for
specific problems in urban water systems are:
- Soil surfaces are heavily sealed by pavements and buildings reducing natural groundwater recharge and increasing runoff volume.
- Natural aquatic ecosystems are heavily modified in their hydrological regime and receive numerous contaminants (e.g. nutrients, micropollutants) due to a combination of sewer overflows and incomplete treatment which have negative effects on the aquatic biota.
- Partially closed water cycles with effluent impaired waters exist but the understanding of the processes in the respective compartments and their transitions is insufficient.
Berlin is a metropolitan area with increasing population depending on large technical urban water systems and having large surface water systems with high importance and value for the society. It is an ideal location for research on urban water interfaces because of challenging hydrological conditions (e.g. moderate precipitation, low river discharges) and strong interactions with feedback of water compartments (e.g. partially closed water cycles) and of natural and technical systems (e.g. bank filtration). A diversity of approaches to address problems in urban water systems is found and can be studied in Berlin to face the urban water related Sustainable Development Goals (UN 2017).