Willingness to pay for ecosystem benefits of green stormwater infrastructure in Chinese sponge cities

Abstract

Globally, green stormwater infrastructure (GSI) has been adopted to address urban flash flooding and stormwater pollution and provide additional ecosystem benefits such as recreation, education, and aesthetics to urban communities. However, there has been a lack of research on people's preferences for different ecosystem benefits, making it challenging to understand synergies and trade-offs among co-benefits and optimize GSI planning and design. Additionally, urban stormwater management programs commonly face long-term financial challenges, demanding research that investigates the feasibility of public utility programs. This study fills these gaps in a Chinese context by employing a discrete choice experiment (DCE) to compare public preferences and estimate the monetary values of four GSI benefits, including stormwater quantity and quality treatment, educational benefit, aesthetics, and recreational benefits, in four small-to-medium pilot sponge cities. Results show that respondents preferred some kinds of GSI programs to a conventional lawn space in their living environments, and they had significant willingness to pay (WTP) for GSI programs to obtain educational ($14.8 per household per year, p < 0.001) and recreational benefits ($10.8 per household per year, p < 0.001). Stormwater treatment, as the environmental benefit prioritized by governmental agencies, however, did not generate a significant willingness to pay in any studied cities. Residents also showed indifference towards three different planting aesthetic styles (i.e., formal vs. mixed vs. naturalistic). We conclude that providing social-oriented benefits such as education and recreation is more likely to garner urban residents' financial support for GSI development in the chosen sponge cities. While stormwater utility can be a viable funding source to supplement urban stormwater management programs, people's WTP remains limited, and other financial mechanisms need to be explored.