Assessing the impact of water reuse for agricultural and urban irrigation based on the ecosystem service framework: evidence from a German case study

Facing changing conditions like climate change, water-stressed regions are exploring alternative water supply options, including water reclamation for agricultural and urban irrigation purposes. While required technologies are available, highly flexible and demand-driven management strategies for water reuse in urban and agricultural irrigation are still in an early stage of development, especially in Germany. The project ‘Nutzwasser’ successfully demonstrated a water reuse system using advanced treated municipal wastewater for agricultural and urban irrigation and performed a holistic cost–benefit analysis (CBA) to assess the economic feasibility of the approach. This CBA combines the concepts of life cycle costing and ecosystem services, which were used to develop a use-case-specific indicator-based evaluation matrix with decision-relevant economic indicators and ecological endpoints. The matrix was then applied to a German case study in order to quantify the technology-induced changes in local ecosystem services and their corresponding costs. The application of the assessment approach proved that the ecosystem service concept is suitable for showcasing the benefits of water reuse systems. At the same time, it became evident that there is further improvement needed in order to overcome existing challenges with regard to input data availability.