Green roofs are being incorporated into stormwater management programs around the world. While numerous studies have estimated the private benefits to the owners and residents of buildings with green roofs, the value of the multiple public benefits received by non-building residents are less well known. We use a choice experiment survey to estimate the public benefits for a proposed green roof program in Portland, Oregon, USA. These benefits include reduced combined sewer overflows, reduced urban heat island effects, and an increase in pollinators such as birds, bees and butterflies. Past investments in stormwater infrastructure have exposed some residents to poor water quality and urban flooding, so we also explore if respondents’ willingness to pay varies based on where new green roofs are located. Across models, the largest estimated benefit in our study area is from a reduction in combined sewer overflows. Model results also show that respondents prefer to not fully concentrate new green roofs in Portland’s Central City area, which is where most green roofs are currently located. Total willingness to pay estimates for the 1-year program range from around $202 to $442 per household, or $54.4 to $116.8 million for the city of Portland, Oregon, depending on program characteristics.

绿色屋顶正被纳入世界各地的雨水管理计划。虽然大量研究估计了绿色屋顶建筑物的业主和居民的私人利益，但非建筑居民获得的多种公共利益的价值却鲜为人知。我们使用选择实验调查来估计美国俄勒冈州波特兰市提出的绿色屋顶计划的公共利益。这些好处包括减少综合下水道溢流，减少城市热岛效应，以及增加鸟类、蜜蜂和蝴蝶等传粉媒介。过去对雨水基础设施的投资使一些居民面临水质差和城市洪水的风险，因此我们还探讨了受访者的支付意愿是否因新绿色屋顶的位置而异。跨模型，在我们的研究区域中，最大的估计收益来自于减少合流下水道溢流。模型结果还显示，受访者不希望将新的绿色屋顶完全集中在波特兰的中心城区，这是目前大多数绿色屋顶所在的地方。根据计划的特点，为 1 年期计划支付估计的总意愿从每户 202 美元到 442 美元不等，或俄勒冈州波特兰市的 54.4 美元到 1.168 亿美元不等。