Adoption determinants and policy tools for residential green stormwater infrastructure: A review synthesizing differences and commonalities among lot-level practices.

Climate change adaptation in intensifying urban environments benefit from green stormwater infrastructure (GSI) investments on private residential yards. Nevertheless, planners are challenged to devise policy tools to mesh such a decentralized GSI approach with current land-use and social systems. Prior research has addressed the multi-scalar socio-economic barriers hindering household uptake, including technical and governance considerations. However, the interconnectedness of these factors has not received much attention. Additionally, studies into GSI often analyze a specific GSI but then overgeneralize their conclusions about adoption determinants for a range of GSI practices. Our review aims to refine previously ambiguous generalizations by comparing adoption factors for three distinct GSI practices: rain gardens, rainwater harvesting, and permeable pavers. We systematically identified 1753 studies and conducted a full content analysis of 56 studies, defining 17 explanatory factors and discussing their independent influences on the three GSI practices. Our results suggest that adoption factors vary between GSI practices, highlighting the need for practice-specific policy tools. Using the Fogg Behavioral Model as a qualitative framework, we illustrate and synthesize the interplay between motivational and ability factors and propose potential targeted policy interventions for each GSI practice. Evidence from different contexts on the three practices suggests that neither stimulative policy instruments (e.g., providing cost subsidies) nor restrictive tools (e.g., enforcing minimal infiltration rates) are efficient in isolation. Our results can guide scholars, decision-makers, and professionals to craft practice-specific integrated policy packages, accounting for socioeconomic factors to achieve transformative GSI uptake.