Climate Change
Impact on water supply and sanitation
BANGLADESH is exposed as one of the most vulnerable countries in terms of adverse impacts of climate change due to its geographical location, hydrological influence of monsoon and regional flow patterns, high rainfall during monsoon while little in the dry season, extreme temperature with scanty rainfall, saline water intrusion, catastrophic natural disasters, etc. However, water supply and sanitation are projected to be in peril under the impacts of climate change. Safe drinking water is likely to become an acute problem particularly in the coastal belt and in the north-western part (drought-prone areas) of the country for salinity and decline of groundwater, respectively. Intermittent and unexpected annual rainfall as well as very low water flow in the major river system badly affect the recharging process of the groundwater. It is noted that, only groundwater is used for safe drinking and irrigation purposes in Bangladesh. As a result, groundwater is being polluted by hydro-geologic process that affects, especially women and children, in terms of human health and well-being and safe drinking water. The impacts of climate change on water supply and sanitation directly affect sustainable development of the country and put at risk poverty reduction, mother and child care, overall public health as well as existing ecosystems. Water supply and sanitation are to be crucially affected by climate change in many ways in Bangladesh. Some are given below: Rainfall: Since the variation of rainfall will be sensitive in terms of geographic locations, many areas will endure water logging, turbidity as well as sedimentation problems in the country. Availability of fresh water will decrease due to salt water intrusion and regional rainfall patterns. Occurrence of water-borne diseases will increase while water treatment and water supply infrastructure will face challenge. Rainfall is one of the most major components for recharging groundwater. Thus, water options could be experienced on seasonal water depth variations in terms of layer status. Meanwhile, there is acute water stress in the high Barind tract regions, where surface water and groundwater have shown an alarming situation vis-a-vis irrigation and safe drinking water. Increased rainfall brings water borne infectious diseases from one place to another through runoff whereas scanty rainfall often leads to desertification in an area. A number of people will lose year-round access to safe drinking water and sanitation due to increased and irregular rainfall. Thus, recurrent costs for water supply, sanitation and public health will increase. Temperature: Temperature is also predicted to rise by 0.7°C in summer and 1.3°C in winter by 2030 while it would be 1.1°C in summer and 1.8°C in winter by 2050. If the temperature increases according to the predicted scale, temperature of surface water will be increased and then evaporation will bring increased demand for irrigation. Meanwhile, a number of places are not getting adequate irrigation and drinking water during summer in Bangladesh. Due to these decreasing parameters, public health will be in danger. Increased temperature can be one of the most important reasons for decrease in soil humidity, top soil degradation, constraint for seed germination as well as overall agriculture that would aggravate livelihood and public health. Drought: Land degradation has been an ongoing process in the north-western part of Bangladesh where soil fertility, soil nutrients, humidity as well as overall agricultural production are much lower than that in other areas. Drought reduces availability of surface water, leads to over extraction of groundwater, causes decline in recharging processes of groundwater. Moreover, drought leads to low productivity of agriculture that affects livelihoods. Flood: Flood would be one of the most adverse impacts of climate change in the context of Bangladesh since about 80% of its total area is virtual floodplain. The flood frequency will lead to reduced water quality and increased scarcity of safe water. Risks will be higher for water treatment and supply infrastructure. Symptom of skin diseases, cholera and diarrhea as well as water borne infectious diseases will be exposed and increased. Sources of water points and sanitation could have been extinct, since flood destroys them, and recurrent costs will be higher in this regard. Sea level rise and salinity intrusion: Global sea level rise due to ice melting induced by global warming is aggravating the uniform cycle of climate of Bangladesh. It is predicted that, the sea level may rise by 30 and 50 cm by 2030 and 2050, respectively. Such impact will lead to displacement and resettlement of approximately 6-10 million people by 2030 and 20 million by 2050 in the coastal region as climate refugees. The coastal area covers about 20% of the country. Sea level rise and salinity intrusion will reduce fresh water options where already 53% of the area has been affected by salinity. This could increase expenses for water treatment mechanism. Saline water intrusion into groundwater will be increased due to low elevation as well as hydraulic structures. In turn, access to safe drinking water options can be dramatically reduced. This changed physical environment will affect public health issues and coastal livelihoods. Adaptation is the process which can be created as well as practiced with indigenous or semi-technical heuristic knowledge of community to reduce adverse impacts of climate change on their health, well-being, livelihood and existing ecosystem. However, adaptation and structural measures like integrated water resources management, health, hygiene, and behavioural changes of community could be fruitful to sustain water supply, sanitation and public health in Bangladesh.
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