Rainwater Harvesting-based Safe Water Access in Diarrhea-endemic Coastal Communities of Bangladesh under Threats of Climate Change

The highly populated coastal floodplains of the Bengal Delta have a long history of water-related natural calamities such as droughts, floods, and cyclones. Population centers along the floodplain corridors of the GBM (Ganges-Brahmaputra-Meghna) river system remain vulnerable to such natural hazards and waterborne epidemic outbreaks due to increasing intensity and changing frequency of extreme events over many areas in the delta region. Such changes in hydrologic extremes and resulting environmental conditions would likely lengthen the transmission seasons of prevalent waterborne diseases and alter their geographic range as well as seasonality. In addition, the combination of changing upstream precipitation and temperature, and coastal sea-level rise are exposing a vast area in Southwestern Bangladesh to increased diarrheal disease outbreaks due to higher salinity and water scarcity in the dry season as well as coastal flooding and water resources contamination in the wet season. It is thus essential to establish sustainable safe water access practices in these regions for the rural communities of low-income people.

The impact of climate change in the recent past on the people of coastal rural areas of Bangladesh has been severe, and the water sector is one of its biggest victims. Previously, pond and groundwater sources were considered dependable, but salinity intrusion in both water resources have left the vulnerable people with only a few scarce ponds and forced them to depend more on rainwater than before. The poorest group is suffering the most for this crisis even though paying more of the percentage of their income especially in the dry season (December-March). As rainwater is their most preferred and dependable option during this part of the year, outbreaks of waterborne diseases can be minimized by installing rainwater harvesting systems with effective disinfection system at both household and community levels. In this study, we explore the technical feasibility and optimum scales and designs of rainwater-harvesting schemes in areas under changing precipitation patterns and coastal sea-level rise. We present preliminary results based on changing rainfall patterns, water budget analysis, and rainwater harvesting potential.