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Dacope Upazilla under Khulna district is one of the most affected safe water scarcity regions like any other part of southwest coastal region of Bangladesh. The demands for drinking and cooking water in the area are mostly met from rainwater harvesting and pond water. Pond water from different stations of Dacope Upazilla was analyzed for assessing the water chemistry, source rock evaluation and its potability status. Thirty one samples were collected by purposive sampling and analyzed following standard methods. The analysis reveals that the cations and anions of the ground water showed the order of abundance as Na+> Mg++>Ca++>K+ and Cl->SO4 -->HCO3 - , respectively. Source rock deduction suggests that the water is mostly carbonate weathering of sea water or brine intrusion. Piper diagram suggests that the water is in saline condition. Ionic ratios also justify the aforesaid relations. The chemical constituent of water is (Na++K+) and (Cl- +HCO3 -) type influenced by sea water, however, ponds are in transition zone influenced by tide. With reference to Bangladesh and WHO standards the research states that most pond water do not satisfy the potable quality, therefore management options need to be formulated for further exploitation. Asiat. Soc. Bangladesh, Sci. 44(2): 159-171, December 2018

The ecosystem of the SouthWest coastal area of Bangladesh is resourceful and unique. Regrettably, this distinctive area is vulnerable to numerous climatic factors, for instance, sea water intrusion, temperature variation, unpredictable behavior of rainfall, and frequent occurrence of cyclones and drought. Undesirably, the effects of those climatic factors have been enhancing on account of human behavior, one of which is the frequent change of land-use pattern in this area. The land-use pattern of the coastal Bangladesh has been changed continuously over the last 60 years in order to increase the agricultural production for improvement of livelihood. The unrealistic improvement projects (coastal embankment project, increased unscientific shrimp cultivation, and so on) brought the unforeseen disaster in the area. As a result, the salinity level of the area has been increased considerably, resulting in decreased production of different kind of crops and vegetables. Unstable economy and the emergence of calamities, leading to damage to ecology and ecosystem, made livelihood insecure in the area.

Urban greenspaces can affect the physical and mental health of city residents and they can also contribute to improving urban environmental quality in ways that can benefit human health. Dhaka, a megacity with over 22.4 million residents, has progressively lost its greenspace over the past decade as the city has grown and urbanised. This study evaluates the availability and accessibility of greenspace considering its population and residential areas, as well as assessing the changes to greenspace in the last 30 years throughout the city. We utilized secondary data from the 2011 Census and areal imagery to perform the analysis for city wards, the smallest administrative unit, using ArcGIS software. We generated geospatial maps of greenspace distribution and accessibility as well as vegetation, land surface temperature and humidity in different years. Accessibility to greenspace was measured with 100-meter and 300-meter buffer zones, and a total of 56.5 square kilometers area of 77.47 square kilometers of residential area fell under these territories. Changes in vegetation were obtained using Normalized Difference Vegetation Index (NDVI) for the years 1990, 2000, 2010, and 2020, and a high level of loss in vegetation was observed. Land Surface Temperature (LST) and Normalized Difference Moisture Index (NDMI) were used to assess the temperature and humidity for the same years. We measured that Dhaka has 2.24% greenspace coverage and only 2 wards out of 110 have greater than 20% greenspace coverage. A highest estimate of 0.003207 square meter per capita greenspace was found at ward-46, which does not even meet the minimum health standard. Increased temperature and decreased humidity were observed in Dhaka city from 1990 to 2020, in a level that may adversely impact on the city population’s public health. We found a high correlation between NDVI with LST and NDMI. In 49% of wards, vegetation and humidity decreased, whereas temperature increased. This study provides noteworthy information on the lack of greenspace throughout Dhaka city. The spatial distribution of greenspace provided in the study has the potential to be useful in taking measures for improving sustainable greenery management in the city area and the health of Dhaka’s growing population.