Using best-worst scaling to reveal preferences for retrofitting raingardens in suburban streets

Raingardens are increasingly common in sustainable stormwater management in cities around the world. Implementing raingardens will change the appearance of conventional urban streetscapes and this is especially important when retrofitting raingardens into existing streets. Raingardens need to fulfil both technical and aesthetic functions. Aesthetic function, assessed as landscape preference, must be understood to ensure that retrofitted raingardens are appropriately designed and managed. Scholars have long adopted a Likert rating scale- to determine landscape preference. Limitations of this method led market researchers to develop choice-based ranking, including best-worst scaling, to assess preference. Thus, this study uses best-worst scaling to assess landscape preference by residents for pairs of streetscapes with and without raingardens in four suburbs of Melbourne, Victoria, Australia. These preference data, and attitudes towards raingardens, stormwater harvesting and own streetscapes, inform guidelines for design and management of retrofitted raingardens. Findings revealed respondents’ overwhelming support for harvesting and reuse of stormwater, though support for fit-for-purpose stormwater reuse decreased as personal proximity increased. While attitudes towards raingardens were positive and most respondents liked the raingardens in their own street, less than one-quarter helped to maintain them. Across all respondents, maintenance of raingardens in streetscapes was regarded as the responsibility of local government. Nevertheless, many would install raingardens in their own property. Overall, streetscapes with raingardens were preferred to those without. Residency in a street with or without raingardens did not influence preference, however, residency in a particular street did. Indeed, context was important: preference for one's own streetscape varied statistically significantly between residents of inner- and outer-Melbourne suburbs. Drawing on these results, four guidelines for design and management of retrofitted raingardens are proposed: 1. Understand context; 2. Consider how the street is used; 3. Select appropriate plants and planting style; 4. Ensure adequate maintenance.