Urban Rainwater Management Using the Aquifer for Storage as One Measure to Confront Changed Water Availability

Abstract

This paper presents an adapted set-up for urban rainwater management since the upscaling of the classical set-up tends to be problematic. It is found that this is mainly due to the high investment costs required for the construction of storage elements such as tanks or cisterns. The general idea of the proposed set-up, therefore, is to combine the decentralized catchment and infiltration of rainwater at household level with a centralized water supply system. The water supply of the households is provided through a high connection rate to the water supply system, exploiting the local groundwater resources. The rainwater is infiltrated on-site into the subsoil and stored in the local aquifer allowing for indirect reuse in the households through the water supply system. The proposed set-up requires the existence of a competent water management institution and the implementation of an appropriate management model. Possible benefits and important challenges of the proposed set-up are discussed herein, as well as a future extension including on-site treatment of greywater. It is concluded that the proposed set-up could be very beneficial to achieve sustainable usage of groundwater resources in the urban context. However, there is no experience, since the proposal has not been implemented yet.