Planning for green infrastructure and mapping synergies and trade-offs: A case study in the Yanshuei River Basin, Taiwan

Climate change has caused various issues for our society and the environment. To decrease these impacts, abundant urban green infrastructure is considered a significant policy strategy. Green infrastructure provides a variety of social and ecological benefits, from improving mental health to managing flood conditions. Although previous studies have provided many planning approaches for green infrastructure, the kind of green infrastructure spatial configurations that can maximize co-benefits remains to be explored. Moreover, the spatial distribution of the synergies and trade-offs between co-benefits should be discussed. In this article, we applied the bivariate local indicator of spatial autocorrelation (BiLISA) to identify the spatial distribution of synergies and trade-offs between different co-benefits. We then built a Green Infrastructure Spatial Planning (GISP) model to set up three different scenarios, including plan orientation and centralized and decentralized green infrastructure planning. Ultimately, we evaluated accessibility to green infrastructure by GIS and surface runoff by Soil and Water Assessment Tools (SWAT) in these scenarios. The results showed that spatial heterogeneity exists in the synergy and trade-off relationships between diverse co-benefits, thus providing a new perspective for researchers to have more systematic studies associated with this issue. According to the Green Infrastructure Spatial Planning model that we built, the prioritization for green infrastructure is located in Annan District and North District in the Yanshuei River Basin. In addition, the effect of runoff reduction is better with decentralized green infrastructure planning; that is, smaller units of green infrastructure with a separate configuration are more effective in reducing runoff. Furthermore, the average accessibility to green infrastructure of decentralized green infrastructure planning is higher than that of the centralized scenario. In conclusion, decision-makers and planners should consider planning green infrastructure in a decentralized way to enhance the resilience and sustainability of one area.