Drinking water vulnerability to climate change and alternatives for adaptation in coastal South and South East Asia.

M. A. Hoque,A. P. Butler,K. M. Ahmed,A. E. Khan,P. F. D. Scheelbeek,P. Vineis

doi:10.1007/s10584-016-1617-1

Abstract

Drinking water in much of Asia, particularly in coastal and rural settings, is provided by a variety of sources, which are widely distributed and frequently managed at an individual or local community level. Coastal and near-inland drinking water sources in South and South East (SSE) Asia are vulnerable to contamination by seawater, most dramatically from tropical cyclone induced storm surges. This paper assesses spatial vulnerabilities to salinisation of drinking water sources due to meteorological variability and climate change along the (ca. 6000 km) coastline of SSE Asia. The risks of increasing climatic stresses are first considered, and then maps of relative vulnerability along the entire coastline are developed, using data from global scale land surface models, along with an overall vulnerability index. The results show that surface and near-surface drinking water in the coastal areas of the mega-deltas in Vietnam and Bangladesh-India are most vulnerable, putting more than 25 million people at risk of drinking ‘saline’ water. Climate change is likely to exacerbate this problem, with adverse consequences for health, such as prevalence of hypertension and cardiovascular diseases. There is a need for identifying locations that are most at risk of salinisation in order for policy makers and local officials to implement strategies for reducing these health impacts. To counter the risks associated with these vulnerabilities, possible adaptation measures are also outlined. We conclude that detailed and fine scale vulnerability assessments may become crucial for planning targeted adaptation programmes along these coasts.Electronic supplementary materialThe online version of this article (doi:10.1007/s10584-016-1617-1) contains supplementary material, which is available to authorised users.

Highlights

The landscape of South and South East (SSE) Asia is characterised by the Himalayan Mountains, and its associated topography and diverse river systems
Along the (South East and South Central) coasts of Vietnam shallow groundwater is the dominant source of drinking water, with ca. 60 % of households provided by hand dug-wells, and a further ca. 25 % of households through drilled wells; the remaining 15 % of the population relying on surface water and rainwater (Snelgrove and Patrick 2009)
The analysis indicates that the Vietnam coast is most vulnerable along the Asian coasts, and the coastal zones of West Bengal of India and Bangladesh are moderately vulnerable

Summary

Introduction

The landscape of SSE Asia is characterised by the Himalayan Mountains, and its associated topography and diverse river systems. The continental rivers that drain the Himalaya and adjacent areas give rise to some of the world’s largest mega-deltas (Bengal, Irrawaddy, Chao Phraya, Mekong and Red River), which are located along the coasts of SSE Asia. This riverine-landscape coupled the mighty Asian monsoons (with distinct wet and dry seasons) provides people with agriculture-based economic opportunities along the coastal regions. In the Mekong and Red River delta regions >50 % of households rely on surface water and harvested rainwater (Snelgrove and Patrick 2009) because shallow groundwater is unsuitable due to its high iron content and salinity, coupled with an offensive taste and smell (Delta Alliance 2011)

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