Urban flooding is a common natural hydrometeorological disaster for many countries in Asia and the Pacific including Indonesia, Malaysia, and Philippines. Bandung is one of the cities in Indonesia where intense rainfall would often lead to severe flooding due to several causes; the most important being a conversion of recharge source locations into residential areas. Similar cases can also be found in Malaysia and Philippines. In Kuala Lumpur, Malaysia, flashflood hazard is closely associated with rapid development, deforestation, reduction of green areas, and the construction of watertight roofing and concrete (Samsuri, 2018). Lastly, Philippines is described as the world's third most vulnerable country to extreme climate events and natural hazards due to natural and man-made factors. The National Climate Change Action Plan highlights that its vulnerability is also the result of ecosystems degradation such as land conversion, the diversion and storage of freshwater in dams, as well as the loss of mangroves and coral reefs.

To mitigate flood-risks in densely populated and urbanised cities, the Nature-based Solutions (NBS) approach to adaptation would be very well-suited to tackle the issue as the application would allow connecting the green (i.e. vegetation), blue (i.e. water) and grey infrastructure (i.e. unsealed roads), which would positively contribute environmentally, socially, culturally, and economically. However, the application of NBS remains untested and unrealised in Southeast Asian countries, especially in the three countries identified in this study. Hence, this study aims to fill-in the gap by providing innovative recommendations and solutions using the NBS approach to reduce high-risk of flood disasters precipitated by rapid urbanisation. To do that, there will be three phases of activities in this research: (1) critical review of current NBS schemes and to obtain some data related to NBS implementation in selected SEA countries; (2) develop the NBS opportunity spatial planning tool in Kuala Lumpur (Malaysia), Bandung (Indonesia) and Manila (the Philippines); lastly, (3) develop local knowledge-based strategies and an NBS network by engaging stakeholders and communities in the regions and disseminating the research outputs.