Are Deep Tubewells Safe and Equitable? A Geographic Examination of Impacts of Deep Tubewell Interventions on Provision of Safe Drinking-water and Diarrheal Diseases in Rural Bangladesh

Arsenic poisoning and childhood diarrhea are major drinking-water related problems in rural Bangladesh. To mitigate these problems, thousands of deep tubewells that extract ground water from the deep aquifer have been installed. Deep tubewells typically have lower arsenic and microbial contamination than widely used shallow tubewells at source. However, the effect of deep tubewell use on childhood diarrhea is not well understood and there are concerns that reliance on these tubewells may have unintended health consequences. Compared to shallow tubewells, deep tubewells are more expensive and located farther away from most households. Despite lower risk at source, households that rely on deep tubewells may store their water longer and have higher risk of contamination at point-of-use.This project investigates the effectiveness of deep tubewell interventions to provide safe drinking-water and reduce diarrheal disease risk in under-five children in rural Bangladesh. I examine the role of geographic context to determine situations under which these interventions work best. By doing so, I address three often overlooked challenges in measuring effectiveness of population health interventions: 1) potential for unintended consequences, 2) potential for spatial variation in the effectiveness of an intervention, and 3) role of geographic factors at multiple spatial scales. I integrate detailed groundwater and drinking-water microbial data, health and demographic surveillance data, and spatial data across 142 villages in Matlab, Bangladesh.I find that households that use deep tubewells are exposed to higher microbial contamination in drinking-water due to increased travel time compared to shallow tubewell households. However, such findings do not translate to higher diarrheal disease incidence among under-five children. Conversely, children in households that use deep tubewells have lower diarrheal disease risk compared to children in households that use shallow tubewells. Geographic context matters and environmental factors such as seasonality, being located in flood control areas, behavioral factors such as sanitation, and social factors such as tubewell ownership influence how effective such interventions are. Additionally, there is considerable spatial variation and using a deep tubewell protects against diarrheal disease only when a large proportion of the neighboring households also use deep tubewells as their primary source of drinking-water.Doctor of Philosoph