Projecting Urban Water Resilience in Bangkok and Hanoi

Callenge

Bangkok and Hanoi face worsening water stress from rapid urbanization, climate change, and shrinking agricultural land.

Solution

Researchers modeled climate, land-use, and water trends to support city planning and resilience-building for future water security.

Overview

Rapid urbanization and climate change are driving water-related risks in Southeast Asia’s megacities. Bangkok and Hanoi, two of the region’s fastest-growing urban centers, face mounting challenges from rising temperatures, changing rainfall patterns, urban sprawl, and overstretched infrastructure. Future water security in both cities is uncertain amid expanding populations and land conversion from agriculture to concrete.

An Asia-Pacific Network for Global Change Research (APN)-supported project led by Sathaporn Monprapussorn (Srinakharinwirot University, Thailand) examined the interplay between climate change, land-use change, and urban water systems.

The project used downscaled climate data, spatial land-use modeling, and hydrological simulations to project future water demand and availability. The research focused on three climate and development scenarios projected to 2050: business-as-usual, rapid economic growth, and green growth.

The researchers partnered with Vietnamese and Thai research institutions and consulted with local officials and stakeholders to ensure local relevance. The project’s findings can guide sustainable urban planning and inform cross-sector water management policy.

Methodology

The researchers integrated climate modeling, land-use simulation, and water demand forecasting. Climate data were derived from the HadGEM2-ES model (a global climate model developed by the UK Met Office that includes atmospheric, ocean, and land surface components), downscaled to the city level. They also used the CLUMondo land-use model (a dynamic, scenario-based spatial modeling tool used for simulating changes in land-use systems and patterns over time) to simulate future land cover change in Bangkok and Hanoi under the three scenarios.

Water demand was estimated using the Water Evaluation and Planning (WEAP) tool (a user-friendly software platform developed by the Stockholm Environment Institute for modeling water demand, supply, and allocation scenarios), which integrates land-use, climate, and population data to project water system performance.

The analysis considered water demand per capita and infrastructure constraints, integrating various socioeconomic and environmental driving forces. Temperature and rainfall shifts were analyzed alongside urban land expansion to model future water supply-demand balances.

Local stakeholder consultations included meetings with city planning departments, water utility managers, and environmental agencies in Bangkok and Hanoi. These consultations, combined with analysis of spatial land-use data and input from academic and government institutions, helped validate key modeling assumptions and refine the design of urban growth and water demand scenarios.

Key Results and findings

• Average monthly temperature in Bangkok is projected to increase by 2.3°C by 2050; rainfall may decline. For Hanoi, average monthly temperature is projected to increase by 2050, while annual rainfall is not predicted to increase significantly, though daily precipitation could increase in some regions of Vietnam.
• Both cities will see continued urban expansion, which will encroach on agricultural and green areas.
• Per capita water demand in Bangkok already exceeds 340 liters per day, based on 2013 data, and is expected to grow further due to continued population growth, economic development, and increased temperatures, factors that together place additional stress on water supply systems.
• Challenges exist in water governance and infrastructure capacity, requiring improved coordination between urban and regional agencies.
• Green growth scenarios, which emphasize compact urban development, conservation of green space, and low-carbon infrastructure, help retain more green space, easing pressure on drainage and water retention.

Outputs

• Integrated urban scenario models for Bangkok and Hanoi.
• Climate-adjusted projections of urban water demand to 2050.
• Land-use change maps under a business-as-usual scenario (continuing current trends in development and land use), rapid growth scenario (characterized by accelerated economic development and urban expansion), and green growth scenario (prioritizing environmental protection, compact city planning, and conservation of green spaces).
• Stakeholder workshops included sessions with Bangkok’s Department of City Planning, the Hanoi People’s Committee, water utility operators, university researchers, and urban environmental planners to review model projections and co-develop adaptation strategies tailored to each city’s specific challenges.
• Policy suggestions included promoting green infrastructure such as parks, permeable surfaces, and retention basins to reduce runoff and improve urban cooling. Basin-level water planning recommendations emphasized coordination among urban planning agencies, environmental authorities, and river basin organizations to manage water supply and demand more effectively across jurisdictions.

Future outlook

The project highlighted the need for coordinated planning across sectors. For both cities, this means improving climate resilience through green infrastructure, zoning reform, and basin-wide cooperation. Future planning for Bangkok could focus on strengthening coordination between urban and river basin agencies, and for Hanoi on sustainable land-use controls and better integration of climate data into infrastructure planning.

Future research could also explore increasing urban socio-ecological resilience through effective mitigation and adaptation strategies. Long-term planning should also consider aspects such as water quality and drought risk.

Project details

Acknowledgement

This project was supported by the Asia-Pacific Network for Global Change Research (APN). The project team acknowledges the contributions of Le Phuong Ha (Vietnam Institute of Meteorology, Hydrology and Environment), Montana Khamsanit (research assistant), Thai university partners, and local officials who provided data and technical input.

Related information

• Monprapussorn, S. & Ha, L. P. (2018). Final report: Integrated analysis of climate, land-use and water for resilient urban megacities: A case study of Thailand and Viet Nam. https://www.apn-gcr.org/publication/project-final-report-caf2015-rr19-nsy-monprapussorn/
• Monprapussorn, S., & Ha, L. P. (2021). Integrated analysis of climate, land use and water for resilience urban megacities: A case study of Thailand and Viet Nam. APN Science Bulletin, 11(1). doi: 10.30852/sb.2021.1556
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