Reservoir water quality: a case from Jordan

Jordan relies heavily on reservoirs building and development to cope with water supply challenges, where monitoring and assessment of reservoir water quality are critically important for the sustainable use of these water supplies. Mujib Dam is an important water supply source in central western Jordan. Evaluation of water quality parameters and their spatial distributions (vertical and horizontal) showed near-neutral pH values with nearly similar values from surface to bottom. The vertical profile of DO and TDS in the dammed reservoir showed slight decreasing trends with increasing depth. Although Ca, Mg, Na, and K concentrations varied slightly with depths, their variations showed no trends. Similarly, the vertical and horizontal distribution patterns of Cl, SO₄, HCO₃, NO₃, and PO₄ in Mujib reservoir water showed insignificant variations in surface water layer and relatively unchanged values or decreasing trends through the water column. Higher values of TN have been observed, especially in the western part, suggesting that agricultural activities and livestock farming in the upstream catchment are impacting water quality. Results revealed that weathering and dissolution of rocks are the major source of water chemistry. The majority of trace metal levels (Cd, Cr, Cu, Fe, Mn, Pb, Zn, Co, Ni, Sr, and B) in water showed relatively similar surface and bottom values. The concentrations of COD and BOD₅ in surface water were relatively low with higher concentrations observed in the northwestern corner, coincided with higher levels of chlorophyll a. The average ratio of TN to TP in surface water suggests that phosphorus is the limiting factor for the algal blooms, whereas the average chlorophyll a level in surface water indicates oligo-mesotrophic water.     

Examination of land use/land cover changes,urban growth dynamics,and environmental sustainability in Chittagong city,Bangladesh

As in many other developing countries, cities in Bangladesh have witnessed rapid urbanization, resulting in increasing amounts of land being taken over and therefore land cover changing at a faster rate. Until now, however, few efforts have been made to document the impact of land use and land cover changes on the climate, environment, and ecosystem of the country because of a lack of geospatial data and time-series information. By using open source Landsat data integrated with GIS technologies and other ancillary data, this study attempts to classify land use and create land cover maps, enabling post-classification change detection analysis. By this method, we document the spatial and temporal trajectory of urban expansion in Chittagong, the second largest city in Bangladesh, over a 36-year period. The findings suggest that, over the study period, 56 % of the land cover has undergone change, mainly because of the expansion of built-up areas and other human activities. During the 36-year period, the built-up area around Chittagong city has expanded by 618 %, with an average annual rate of increase of 17.5 %. As a result of rapid urbanization, the vegetated hills near urban development areas face serious threats of further encroachment and degradation, given that 2178 ha of hills have already been intruded over the study period. Because urbanization processes in Bangladesh have traditionally been viewed as the result of population growth and economic development, very little work has been done to track the potential growth trajectory in a physical or spatial context. This study, therefore, will contribute to the current understanding of urban development in Bangladesh from a temporal and spatial point of view. Findings will be able to assist planners, stakeholders, and policy makers in appreciating the dynamism of urban growth and therefore will facilitate better planning for the future to minimize environmental impacts.