Promoting Rainfed Pond for Town's Water Supply System: A Case Study of Southwest Coastal Region in Bangladesh

Bangladesh coastal area is vulnerable to the changing climatic condition because of its geographic location and low-lying topography, and this vulnerability has been acute due to reducing upland flow during dry period and sea level rise contributing to saline intrusion and inundation of coastal freshwater resources. Over the past 25 years, salinity intrusion in Bangladesh has increased by about 26 percent with the affected areas expanding each year. According to a study by World Bank on 2014, climate change is likely to further increase river and groundwater salinity dramatically by 2050 and exacerbate shortages of drinking water in the southwest coastal areas.

Because of salinity of both groundwater and surface water in the Mongla port municipality area, compound river water and rainfed pond water became the main source of drinking water here. Currently, Mongla port municipality located at coastal belt is supplying water to town dwellers by pipeline with water treatment system taking raw water from both harvested rainwater and limited period of river water through pond.

From physical observation, focus group discussion with water users and interaction with key information providers, study team assessed the quantity of water against the demand and also analysised the quality of water both are satisfied. By using secondary data, study team also analyzed the Mongla river’s water salinity and rainfall intensity for assessing the long run feasibility of it. Result of the study on Mongla port municipality’s water supply shows that it is well functionable system, could be replicated to another coastal area as it is nature-based solution which makes the people and authority to adapt it easily with keeping well-functioning.