Vertical Retention Bodies for Rainwater Retention and Microclimate Improvement — Proof of Concept

This study examines the use of vertical retention bodies for water retention in urban areas. The growing challenges of climate change and its impact on the hydrologic cycle are bringing increased attention to the management of heavy rainfall events and the reduction of the urban heat island effect. The “sponge city” concept offers solutions for local water storage in urban areas as a contribution to climate adaptation. This paper addresses the largely untapped potential of vertical systems and presents a proof of concept for a vertical water storage system. An experimental setup is presented to investigate the water storage capacity of vertical retention bodies using two storage substrates (perlite and vermiculite) with the aim of storing the water accumulating on the roof in the vertical retention body. Under heavy rainfall conditions, maximum water storage capacities of up to 194% for perlite and up to 250% for vermiculite were determined. The findings were then assessed to determine the potential for using retention bodies on building facades. This proof of concept demonstrates the application potential of vertical retention bodies as one component of the sponge city concept. The retention bodies contribute to water storage during heavy rainfall events, the cooling effect of water evaporation and the preservation of the local water cycle.