Design Factors Towards Water Retention Ability of Water-Sensitive Urban Design (WSUD) in Tropical and Subtropical Climates: An Exploratory Literature Review

Water Sensitive Urban Design (WSUD) is a comprehensive approach to managing the quality and quantity of rainwater within urban settings and addressing the challenges posed by changes in natural infiltration and precipitation processes. Green Stormwater Infrastructure (GSI) is a key component of WSUD and is extensively utilized in Europe and the United States. GSI can take many forms. One example of GSI is the rain garden, which is frequently integrated into WSUD practices across various regions and communities. The research question for this study is to find guidance for rain gardens in Southeast Asia. The objective is to identify the design factors that affect water retention ability in rain gardens and to determine the specific measurements that can be applied in Southeast Asia and across the world In similar climates. An exploratory literature review method delves into current examples of design factors influencing the water retention ability of WSUD in the tropical and sub-tropical contexts of Southeast Asia. This research found limited studies focussing on WSUD in tropical and sub-tropical climates, limited discussion on local materials, and how planting design may impact WSUD performance. The research gap highlights the need for standardized measurement units and further exploration into the specific design factors influencing the performance of plants in the context of WSUD in tropical and subtropical climates. Moreover, future studies should explore additional aspects, such as investigating input values for modeling, to improve the capability of calculating water retention ability based on relevant plant factors. Furthermore, it could involve examining the water-absorbing performance of different tree species. Designers must work with researchers to create case studies and compile evidence for effective WSUD in the near future.