Modelling a ‘business case’ for blue-green infrastructure: lessons from the Water Sensitive Cities Toolkit

Abstract

Stormwater management through Blue-Green Infrastructure (BGI) delivers multiple benefits across urban environments. However, current integrated modelling tools fail to provide a simplified way of assessing these benefits. In this study, we reflected upon the development of an interdisciplinary BGI planning-support tool, known as the Water Sensitive Cities Toolkit (the WSC Toolkit) and offer guidance for effective tool development going forward. Based on interdisciplinary research, the WSC Toolkit incorporates a suite of independent sub-modules but can be connected together to provide integrated assessment, allowing evidence-based quantification of multiple benefits associated with BGI, e.g., stormwater treatment and harvesting, stream hydrology, erosion, minor flooding, urban microclimate, etc. Distinguished from other larger complex models, the WSC Toolkit was characterised by its simplicity, modularity and extensibility, providing scenario-based integrated assessment of these benefits. Through case studies, we demonstrated how the WSC Toolkit can be used to support improved decision-making towards maximising the benefits of BGI. We also showed how it can act as a platform for practical application of latest research outcomes and meanwhile encouraging interdisciplinary collaboration. We reflect upon five key lessons that could guide future researchers in developing effective integrated assessment tools, particularly within highly interdisciplinary fields such as BGI. Highlights Multiple benefits of BGI recognised, but lack tools that bridge science and practice.; Reflections on initial journey towards building the WSC Toolkit for assessing the benefits.; It supports collaborative decision making & communication among stakeholders.; Diverse case studies and testing build confidence and trust in new models.; Lessons to guide future development of effective interdisciplinary integrated assessment tools.;

Keywords

• collaborative decision making
• integrated assessment
• modelling
• stormwater management
• sponge city
• water sensitive cities