Water Quality Under Stress: Population Pressure, Environmental Degradation, and Climate Impact: Evidence from Refugee Camps in Cox’s Bazar District, Bangladesh (2016-2024)

In the crowded landscape of humanitarian aid, the provision of clean water is often treated as a matter of logistics: counting pumps, building pipes, and distributing chlorine. Yet water does not exist in a vacuum. It is part of a living system where the health of the ground, the density of the trees, the patterns of the rain, and the sheer number of people living in one place all pull on the same thread. When a large group of people settles suddenly in a fragile environment, they do not just occupy space; they alter the very conditions that determine whether the water remains safe to drink. This interplay between human settlement and the natural world is the focus of a new study looking at the Rohingya refugee camps in Cox's Bazar, Bangladesh. The research moves beyond simple infrastructure counts to ask a harder question: how do the pressures of overpopulation, the loss of forest cover, and shifting weather patterns combine to stress the water supply? By weaving together satellite images, climate records, and water quality tests, the study reveals that the safety of drinking water in these camps is not just a technical challenge, but a complex outcome of a landscape under severe strain.

The story begins in 2017, when more than 700,000 people fled persecution in Myanmar and arrived in the Cox's Bazar district of southeastern Bangladesh. They settled in a confined area that was once covered in broadleaf forests and grasslands. Over the next seven years, this landscape transformed rapidly. The population swelled from a few thousand to nearly one million, creating one of the most densely populated places on Earth. To understand what this meant for the water, researchers gathered data from 2016 to 2024, looking at three main sources of pressure. First, they tracked the settlement itself: how many people lived there, how many shelters were built, and how the land was used. Second, they monitored the climate, looking at rainfall and temperature. Third, they measured the health of the ecosystem, checking how much vegetation remained and how the land surface temperature changed. All of this was then compared against the actual quality of the water found in the camps.

The results paint a picture of a system pushed to its limits. The population growth was staggering, increasing roughly 243-fold between 2016 and 2024. While the physical area of the camps did expand by about 56 percent, it was not enough to keep pace with the people. The amount of land available for each person shrank dramatically, dropping from nearly 58 square meters per person in 2017 to just under 30 square meters by 2024. This crowding coincided with a massive loss of forest cover. Satellite images showed that the lush green vegetation that once covered the hills was replaced by bare soil and makeshift shelters. This change had a direct thermal effect: as the trees disappeared and the ground became covered with bamboo and plastic sheeting, the surface temperature of the camps rose significantly. In 2022, the land surface temperature reached a peak of 34 degrees Celsius, a stark increase from the cooler conditions seen before the camps were established. The loss of trees meant less shade and less natural cooling, creating a hotter, drier environment that made the existing water resources even more vulnerable.

The climate added another layer of difficulty. The region is known for its intense monsoon rains, but the study found that rainfall patterns were becoming increasingly erratic. Some years brought severe droughts, while others delivered overwhelming floods. In 2024, for instance, the pre-monsoon months were exceptionally dry and hot, followed by extreme rainfall later in the year. This volatility disrupted the soil's ability to hold moisture and stressed the groundwater. The researchers noted that the water quality was not just a result of the weather, but of how the weather interacted with the crowded, deforested landscape. The combination of high temperatures, reduced vegetation, and heavy rainfall created conditions where contaminants could easily wash into water sources or where the water itself could become concentrated with salts and pollutants.

Despite these environmental pressures, the study found that the water quality infrastructure did improve in some ways, though the results were uneven. In the early years of the crisis, the camps were overwhelmed, but over time, the number of water points and sanitation facilities grew. The data showed a clear trend of improvement in the chemical quality of the water. Levels of organic waste, measured by chemical oxygen demand, dropped significantly from 2020 to 2023. Similarly, the amount of suspended solids in the water decreased, suggesting that filtration and treatment efforts were working. However, the biological safety of the water remained a persistent concern. While the average levels of bacteria like E. coli decreased over the years, they still frequently exceeded safe limits. The problem was not uniform; the water quality varied wildly depending on where it was tested. Water drawn from deep boreholes was generally consistent and safe, but water from hand-pumps and shallow wells showed high variability. In some years, these shallow sources were heavily contaminated, likely because they were closer to the surface where human waste and runoff could seep in.

The study also highlighted a critical gap in the sanitation system. While the number of toilets and waste treatment plants increased, the capacity to treat the waste did not keep pace with the population. The data on faecal sludge treatment plants showed that in some years, the amount of waste being treated was far below what was needed. Even when the treatment plants were working, the quality of the water they produced was sometimes inconsistent. The researchers found that the water quality was not simply a matter of having a pump or a pipe; it was a reflection of the entire system. When the land was stripped of its trees, when the population density became extreme, and when the weather turned erratic, the water supply became fragile. The study suggests that building more infrastructure alone is not enough. The system needs to be resilient to the specific stresses of the environment, which means protecting the remaining vegetation, managing the land to prevent erosion, and ensuring that water sources are shielded from contamination.

Ultimately, the research presents the refugee camps of Cox's Bazar as a case study of a human and environmental system under stress. The rapid settlement of a large population onto a small, fragile piece of land compressed years of environmental change into less than a decade. The loss of vegetation, the expansion of built-up areas, and the warming of the land surface did not happen in isolation; they moved together, creating a cascade of effects that reached the water supply. The findings suggest that the safety of drinking water in these camps is a system-level outcome, shaped by the interaction of land use, climate, and sanitation. While improvements have been made, the study concludes that the path forward requires a holistic approach. It is not enough to treat the water; the land and the climate must be managed as part of the same solution. The researchers have released a detailed database of their findings, offering a template for monitoring similar situations in the future. Their work underscores that in protracted displacement settings, the health of the people is inextricably linked to the health of the land they occupy.