Urban river restoration in Hong Kong: Assessment, impact, and improvement strategies

River restoration or improvement is widely practiced in cities around the world to promote sustainable urban development. However, post-project evaluation is not commonly performed, and even less evaluated is the social impacts of river restoration. Based on three recently restored river channels in Hong Kong, this study evaluated water quality, biodiversity, and societal perceptions of such projects. Focus was placed on perceptions, assessments, and improvement suggestions from 295 surveyed and interviewed respondents. Results show that the effects of river restoration on water quality were mixed—depending on restoration techniques and site conditions. Restored river sections generally had higher biodiversity as compared to unrestored ones. The restored river sections positively influenced the respondents’ visiting behaviors. The respondents at low-density sites generally reported more positive perceptions and higher ratings on the restoration projects than those at the population-density site. Data analysis shows that respondents’ emotional quality was significantly and positively related to biodiversity, visual attractiveness, air freshness, and auditory environment of the sites. The respondents also provided valuable recommendations on the importance of factors to be considered in the planning and design of river restoration, desired facilities, and decision process. The findings and recommendations are expected to help improve future river restoration in compact cities.