Blue–Green Infrastructure for Flood and Water Quality Management in Southeast Asia: Evidence and Knowledge Gaps

Abstract

In Southeast Asia, projections of rapid urban growth coupled with high water-related risks call for large investments in infrastructure—including in blue–green infrastructure (BGI) such as forests, parks, or vegetated engineered systems. However, most of the knowledge on BGI is produced in the global North, overlooking the diversity of urban contexts globally. Here, we review the literature on BGI for flood risk mitigation and water quality improvement in Southeast Asian cities to understand the scope of practical knowledge and identify research needs. We searched for evidence of local types of BGI in peer-reviewed and grey literature and assessed the performance of BGI based on hydrological, societal, and environmental metrics. The body of literature on BGI in Southeast Asia is small and dominated by wealthier countries but we found evidence of uptake among researchers and practitioners in most countries. Bioretention systems, constructed wetlands, and green cover received the most attention in research. Evidence from modelling and laboratory studies confirmed the potential for BGI to address flooding and water quality issues in the region. However, practical knowledge to mainstream the implementation of BGI remains limited, with insufficient primary hydrological data and information on societal and environmental impacts. In addition, the performance of BGI in combination with grey infrastructure, under climate change, or in informal settlements is poorly studied. Future research and practice should focus on producing and sharing empirical data, ultimately increasing the regional knowledge base to promote efficient BGI strategies.

Spatial Planning and Systems Thinking Tools for Climate Risk Reduction: A Case Study of the Andaman Coast, Thailand

“…The greater focus on the implementation of localized physical urban development projects is also a reaction to the shortcomings of classic formal planning. Such projects can also play an important role for local climate adaptation, for example using water-sensitive urban design or blue-green infrastructure [78]. However, at the same time the urban system as a whole needs to become more resilient and the spatial planning system needs to be set up in a way that encourages and allows climate-adapted development [79].…”

Smart City Thailand: Visioning and Design to Enhance Sustainability, Resiliency, and Community Wellbeing

“…The majority of respondents had experienced both fluvial and pluvial flooding, and it appears that while flood assistance was available in different forms, individuals generally absorbed a large proportion of the flood damage. Green space and WSUD could be an effective pluvial flood management measure, while at the same time providing a more livable urban environment [81][82][83][84][85][86]. As such, increased green space and WSUD features underpinned many of the designs for this project.…”

“…Greater green space/public space is represented throughout the superblock, as guided by the findings of the community surveys. Emphasis on green space is a trend that is also consistent with New Urbanism and has gained some focus in Southeast Asia [85,93,94]. A number of Smart City indexes have included a measure of green space as being a positive indicator of "smartness" [61,[95][96][97].…”

“…The models can be calibrated through expanded IoT data collection, consistent with technology and governance aspects of a Smart City. Furthermore, it has been our experience that WSUD designs, for example, are frequently implemented with little or no post-project monitoring of water quantity or quality, particularly in tropical climates, but this could be addressed using IoT and big data approaches to confirm their benefits [85,136].…”

Spatio-temporal development of the urban heat island in a socioeconomically diverse tropical city

“…2020), improving these settlements is a growing international priority. This priority is reflected in the increasing interest and investment by development banks in nature-based solutions (RISE & ADB 2021; Hamel & Tan 2022) which are a major focus of both the Sustainable Development Goals (United Nations 2021b) and Planetary Health approaches (Whitmee et al . 2015).…”