Browsing by Author "Yimame, Samrawit"

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    Environmental Impact Assessment of Quarrying Activities on the Downstream Section of the Big Akaki Catchment. Addis Ababa, Ethiopia
    (Addis Ababa University, 2020-06-05) Yimame, Samrawit; Asrat, Asfawossen (Professer)
    This study focused on the assessment of the impact of quarrying on the natural environment (water resources and land use land cover), and the vulnerability of the community downstream of the quarry sites within the Big Akaki River catchment, using an integrated geological, hydrogeochemical, land use/land cover and social impact assessment methods. Initial reconnaissance survey to select water sampling areas and assessment of overall operations of quarrying in the area was followed by surface water sampling at the quarry sites and upstream and downstream of the quarry sites, along three major rivers in the catchment. These water samples were analyzed for major physical and hydrogeochemical parameters. The results show that the turbidity, TDS, Temperature of the river waters and most of the ions increased their concentration from upstream to downstream of the quarry sites considered, indicating the clear impact of the quarrying activity on the rivers and directly affecting the community using these river waters for domestic and other related activities. However, it should be noted that this might not suggest chemical pollution only because of quarrying. The land use/land cover change assessment was done by using spatiotemporal data of the area between 2000 and 2020, which enabled to assess~20 years of quarry expansion rate, calculated from the classified image by using standard remote sensing and GIS methods and tools. Landsat_7 ETM+, SPOT-5, SPOT-7 and Quickbird raster data for the years 2000, 2006, 2016 and 2020 have been used land use land cover maps for the years considered, and the net change between 2000 and 2020 have been produced and the change has been analyzed. The results indicate that quarrying sites have been expanded by about 692.68 ha, mainly at the expense of the cultivated (agricultural area) which has decreased by 3941.19 ha during the same period. The social impact assessment conducted by a systematic, structured open and closed-ended questionnaire survey of the quarry workers and residents within the immediate vicinity of the quarry sites indicate multiple problems including dust, noise, vibration, and accumulated water in the abandoned quarry sites caused problem on residents and quarry workers. The study Environmental Impact Assessment of Quarrying Activities on the Downstream Section of the Big Akaki Catchment Environmental Geology and Geohazards Stream Page v indicates that unless properly mitigated by all responsible bodies, the quarrying activity in the area will continue to cause serious damages to the natural environment and the community.