Flexible Urban Drainage Systems

Urban drainage systems are influenced by several future drivers, which affect the performance as well as the costs of the systems. The review of the different future drivers for urban drainage systems illustrates, that no sufficient future predictions for the long operational life span of the systems are possible. To deal with these future uncertainties flexible urban drainage systems are required. The paper combines different analysis of the authors, to ascertain first insights about flexible urban drainage systems. In the present technical literature profound insights about definition, measurement and generation of flexibility for urban drainage systems are missing. Hence the theory of flexibility from other disciplines is transferred to the field of urban drainage. A theoretical basis for flexible urban drainage systems is presented. The thematic priority is the generation of flexibility options for urban drainage systems. On the one hand in an analysis it is verified, that decentralised urban drainage systems offer a higher flexibility than conventional drainage systems. On the other hand a generic framework for the planning and measurement of flexibility options of urban drainage systems in individual cases is presented. The paper illustrates, that a transfer of the general theoretical background of flexibility to the field of urban drainage systems is possible. A definition of flexibility, metrics for the measurement of flexibility and a framework for the identification of flexibility options are substantiated for urban drainage systems. Therewith a basis for the implementation of flexible urban drainage systems is offered.