Synergies and trade-offs in achieving sustainable targets of urban renewal: A decision-making support framework

Urban renewal in high-density cities presents a complex challenge when it comes to balancing social-environmental performance and economic benefits; improvements to the built environment and social wellbeing may be associated with substantial costs and economic loss, and particularly so where land resources are scarce and highly valued. The interplay that takes place between sustainable targets tends to be very complicated. This study proposes a decision-making support framework that can quantify the synergies and trade-offs between economic, environmental, and social targets pertaining to land use change and public open space (OS) provision in urban renewal processes. The proposed decision-making support framework operates at both neighbourhood and building levels, and is comprised of three analytical components: a redevelopment trend analysis module, a three-dimensional land use simulation module, and a sustainable performance evaluation module. One high-density and ageing district in Hong Kong, Yau Mong district, was selected as the case study area for this work. Six planning scenarios were built which reflect various priorities and principles including economic benefits, environmental benefits, the equal distribution of OS provision and enhancing the quality of OS. The findings suggest that there is a trade-off relationship between economic-environmental targets, a synergic relationship between social-environmental targets, and a mediational relationship between economic-social targets. Planning strategies such as rezoning, land use reconfigurations, plot ratio adjustment and the transfer of development rights could be triangulated as strategic approaches by which to maximising the synergies and achieve better sustainability. The study not only contributes to theory by introducing a prototype of a comprehensive decision-making framework to evaluate sustainability performance, but also provides important insights into reconciling the divergent sustainable targets inherent in urban renewal.