Natural infrastructure for integrated urban water management in the Global South: A review and some reflections from Southeast Asia

Abstract:

Rapid urban growth in the Global South exacerbates water management challenges such as flooding and water pollution. While the potential for nature-based solutions to address these challenges is recognized, there is a general consensus that too little is known for efficient implementation of natural infrastructure, be it engineered stormwater management systems, riparian vegetation or parks and forests, in particular in the low- and middle-income countries of Southeast Asia.

This presentation synthesizes the knowledge on natural infrastructure for urban water management in Southeast Asia, with implications for other countries in the Global South. We reviewed both the peer-reviewed and grey literature and focused on two hydrologic services: flood risk mitigation (for both urban and riverine flooding) and water quality management.

I will highlight regional types of natural infrastructure that have long existed in and around Southeast Asian cities, suggesting that the recent attention to natural infrastructure management can benefit from long-held regional knowledge. Some of these natural infrastructure such as rice paddies are understudied in the global literature dominated by research in the Global North.

Next, I will summarize the hydrologic performance of natural infrastructure both in terms of peak flow attenuation and water quality improvement. The findings are regionally disparate, with a few countries concentrating the majority of the publications and lower-income countries having few empirical data on hydrologic performance. While we acknowledge the possibility of a reporting bias, the results still confirm the performance of natural infrastructure and its high potential to become an integral part of urban water management in the region.

Finally, I will identify some key knowledge gaps related to hydrological performance and local environments. Key gaps include the consideration of climate change and the role of natural infrastructure in various types of informal settlements, for example along river corridors or surrounding peri-urban wetlands. I will conclude with a synthesis of the main recommendations for policy design and implementation of natural infrastructure, which have relevance outside the region.