Assessing Socio‑Hydrological Adaptation on Large Riverine Islands in Asia

Challenge

Riverine islands face rising climate risks, erosion, and water stress, while local adaptation often lacks integrated, island-scale evidence.

Solution

Use a socio-hydrology lens to link water and society, compare three island sites, and generate maps and guidance for climate-risk decisions.

Overview

Large riverine islands are home to dynamic communities that live with shifting channels, storm surges, salinity, and seasonal water scarcity. Decisions on water use, livelihoods, and settlement shape risk, and water conditions in turn shape those decisions.

This project, supported by the Asia-Pacific Network for Global Change Research (APN), was led by Pankaj Kumar (Institute for Global Environmental Strategies, Japan). It examined climate change adaptation through a socio‑-hydrology lens, which studies the two‑-‑way interactions between society and water, to understand where and how island residents faced risk and how evidence could support decisions.

The research compared three sites that span major river systems and coastal settings: Dakshin Bedkashi on the Padma Delta (Bangladesh), Sagar Island on the Ganges Delta (India), and Con Dao Island off the Mekong River (Vietnam). The project team reviewed existing information, carried out field surveys, and engaged local actors to document water-related‑ hazards, exposure, and coping strategies.

Methods included household surveys, key informant interviews, stakeholder workshops, field surveys, and geospatial analyses to capture how water availability, quality, and extremes affected health, livelihoods, and mobility. The research team prepared island-scale risk and vulnerability maps for Sagar Island to locate areas for potential interventions to improve water security and reduce losses, and conducted complementary assessments on water supply resilience in Con Dao and on water quality and migration in coastal Bangladesh.

Socio-hydrology and evidence for decisions

Socio-hydrology framed adaptation as a coupled human–water system, not a single-sector issue. The research team combined community-level knowledge with spatial analysis to connect the water-food-health-economy nexus and guide community-based adaptation decisions.

This approach supported comparisons across islands while keeping site contexts distinct, such as salinity and embankment pressures on Sagar, cyclone exposure and freshwater access in Dakshin Bedkashi, and small-island water scarcity on Con Dao.

Study approach and site contexts

Across the three islands, the project team gathered qualitative and quantitative evidence on hazards, exposure, and sensitivity; mapped relative risk at fine scales; and summarized adaptation options already in use.

The work highlighted issues such as access to safe drinking water, erosion and land loss, flood protection, and the role of migration and remittances in household strategies. The project presented island-scale maps and plain language syntheses. These outputs created a basis for discussions with local authorities and communities about practical measures.

Outcomes and results

• Household surveys, key informant‑ interviews, stakeholder workshops, and field surveys conducted across Dakshin Bedkashi (Bangladesh), Sagar (India), and Con Dao (Vietnam).
• Island-scale risk and vulnerability maps prepared for Sagar Island, alongside water-supply resilience analysis for Con Dao and water quality and migration analyses in coastal Bangladesh to support local planning and prioritization.
• Socio-hydrological analyses completed to link water conditions with livelihoods, health, and settlement, informing site‑-specific access to safe drinking water ‑options.
• 14 peer-reviewed journal articles (see APN project page for an extensive list), 1 book chapter, and 1 conference paper produced, alongside the final technical report and site syntheses.

Project details

Acknowledgements

This project was supported by the Asia-Pacific Network for Global Change Research (APN) under its Collaborative Regional Research Programme (CRRP). Acknowledgments also go to Khulna University (Bangladesh), Indian Institute of Technology Kharagpur (India), Vietnam National University Ho Chi Minh City (Vietnam), Hokkaido University (Japan), and Keio University (Japan) for their collaboration on field work, data analysis, and reporting.