On January 27, 2023, the first inspections for the selection of the Cologne pilot areas took place by the StEB Cologne (Luisa Schwab, Ingo Schwerdorf) and the ISWA (Till Jaworski).
In this context, various stormwater management systems were inspected at the Eifeltor freight traffic center (GVZ), in Widdersdorf Süd, and in Junkersdorf with regard to their transformability into rainwater harvesting facilities. In the Bürgerpark (Citizen’s Park) in Cologne-Kalk, the potentials for new rainwater management systems with additional rainwater utilization for drought prevention were discussed, followed by the presentation of a new and multifunctional infiltration system in Cologne-Porz. During the inspections of the different areas, the aim was to identify possible rainwater utilization potentials in the areas so that the areas can be embedded as pilot areas in the AMAREX research project.
With these insights, the Kalscheurer Weiher (Kalscheurer Pond) was identified in the vicinity of the GVZ-Eifeltor as a possible user of the rainwater generated in the area. The pond is very important as a recreational area for the city population during the spring and summer months. Due to a leaky concrete bottom and natural water evaporation, decreases in water level occur, which are currently compensated by extracted groundwater. It must be investigated to what extent the rainwater from the storage channel of the GVZ-Eifeltor can be conveyed by the associated pumping station (see Fig. 2) into the Kalscheurer Weiher. The focus must also be on the quality of the water to be discharged as well as possible treatment processes, since discharge into surface waters is subject to strict requirements.
The Bürgerpark in Cologne-Kalk was selected as another pilot area. The on-site inspection showed that rainwater from a directly adjacent parking garage could be stored in service water reservoirs on 1-2 parking areas (not yet available) to make it available for irrigation of the Bürgerpark. This would relieve impact on the sewer system due to the disconnection of the parking areas. Furthermore, rainwater from the existing play areas could be drained and stored in planting pits with coupled infiltration/tank systems (not yet available).
StEB Köln and ISWA will carry out quantitative modeling, qualitative studies and water law considerations in all pilot areas for further assessment of the potential uses.