Earth Sciences

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3d Modelling for Urban Cadasteral Regestration,Management and Administration; The Case of Bahir Dar Town Ethiopia
(Addis Ababa Universty, 2016-06) Hamid, Ahmed; Berihan, Getachew (PhD)
High rate of Population growth, coupled urbanization and industrialization results for high demand for land. In order to increase availability of land, the government of Ethiopia has introduced the construction of multipurpose buildings which allows vertical expansion rather than horizontal. Due to this mode of expansion there is a need to establish a land tenure system which considers the use and registration of multipurpose buildings in 3D environment. In Ethiopia, using aerial photography for cadastral mapping is not a new thing for the processes of extraction of 2D cadastral layer but most of the time it is not seen using for 3D cadastral registration system. Method of feature extraction in 3D environment using aerial photograph is cheaper than that of LIDAR. 2D cadastral and property registration system cannot solve the problem related to building height and was difficult to standardize building construction, even if it has been employed for a long period of time. 2D cadastral registration system is not able to clearly indicate the property right of individuals having multi-purpose buildings. Due to this it is difficult to register, manage, and visualize their institute condition for decision making and for a given applications such as infrastructure development. This study is intended to examine the applicability of Aerial photo and CGA script for automated 3D objects modeling, design cadastral information system for commonly owned residential building and commercial centers, examine legal and institutional aspects of 3D property information and representation system for land registration, management, administration, urban planning and decision making process in Bahir Dar town by applying 3D GIS techniques. The existing 2D cadastral registration system was carefully assessed and the gaps are well identified prior to propose a new registration system. The ESRI 3D city engine module was used to reconstruct the multipurpose buildings after carried out photogrammetric processes. CGA rule was written for each textures such as wall, roof, road, façade, window and door to produce an automated 3D urban model. From the study it is found that the existing cadastral registration system in Bahir Dar land management and development office does not consider the registration of multipurpose buildings. Due to this a new registration system was proposed to incorporate multipurpose buildings in the future cadastral registration processes. It was also found that a 3D model cadaster supports better in managing increased demand of land and building constructions. Key words: 3D model; Cadaster; aerial photo; CGA rule; Façade; Registration; Management Administration, Bahir Dar
Adsorption Efficieny of Groundnut Shell, Lentil Husk and Orange Peel in the Removal of Selected Heavy Metals in Wastewater
(Addis Ababa University, 2020-07-07) Berhane, Hermon; Tessema, Merid (PhD)
Huge amount of metal contaminated wastewater is discharged in Addis Ababa. Owing to the associated problem of disposal, wastewater presents a very severe environmental challenge. The present work focused on the removal of Cr 3+, Cd 2+ and Ni 2+ from wastewater using groundnut, lentil husk and orange peel as adsorbents. The adsorption efficiency of these agricultural waste products for the metals in tannery wastewater was measured. Batch adsorption experiments were performed at different adsorbent mass (0.025 – 3.5 g), different contact time (30- 240 min), pH of solution ranging from 4 – 9, and constant concentration. The concentration of the selected heavy metals (Cr 3+, Cd 2+ and Ni 2+) in wastewater and standard solutions were determined by flame atomic absorption spectrophotometer. Maximum adsorption efficiency of groundnut shell for the metals Cr 3+, Cd 2+ and Ni 2+ were found to be 90.01%, 97.50%, and 96.79%, of lentil husk 88.82%, 98.15%, and 95.20%. The maximum adsorption efficiency of orange peel were 96.13%, 98.27%, and 92.67% respectively. The present study demonstrated that groundnut shell, lentil husk and orange peel could be employed as effective low cost adsorbents for the adsorption of Cr 3+, Cd 2+ and Ni 2+ in the wastewater sample.
Agricultural Drought Risk Area Assessment and Mapping Using Remote Sensing and Gis: A Case Study of West Hararge Zone, Ethiopia
(Addis Ababa Universty, 2017-06) Negassa, Wondwosan; Tesfaw, Binyam (PhD)
Remote Sensing and GIS Technologies are currently important and timely for draught risk area assessment and mapping. In countries like Ethiopia, experiencing considerable annual regular period of dry seasons, drought is not a new phenomenon. The real drought problem, however, arises when the rainfalls fail to fit with the normal cropping seasons. As this gap brings about eminent crop failure and high yield reduction, drought can be perceived as the quantitative, spatial and temporal mismatch between rainfall and the cropping season. This study aims to identify, analyzing, determining and signifying the impacts of the virtual drought on the local environment and mapping agricultural drought risk prone areas of West Hararge Zone, Oromia region, Ethiopia. In order to effectively realize this goal, efforts were made to collect the ten years (2005-2014) drought behavior data, regarding its onset time, frequency of occurrence, spatial extent, duration and levels of severity on the local environment. In addition, this study utilizes remote sensing data, GIS technology and field observations data. Accordingly, reliable Geo-spatial and temporal data have been obtained through the use of modern Remote Sensing and Geographical Information System. The practical field observations, consultations and discussions played great roles in enhancing the acquisitions of commendable knowledge and experiences on the objective reality of the situation. These data were examined and analyzed to scale up the intensity level of the prevailing drought impacts on the agricultural activities of the local farmers. The general responses to drought and the particular existing correlations between rainfall and crop performances were confirmed using Normalized Difference Vegetation Index, Standard Precipitation Index and Water Requirement Satisfaction Index. Based on the confirmed drought pattern and frequency maps of the three indices, a comprehensive map was produced that indicates agricultural drought risk prone areas of West Hararge Zone. This map shows that 12.34%, 33.89% and 48.48% of the total geographical area of the Zone were slight, moderate and severe agricultural drought risk areas, respectively. The result map was validated based on ground based field data obtained from organizational documents and local field professional practitioners. The validation result show significant relation with a correlation coefficient of r = 94 or R² =88. This result map was based on the robust and timely methods and could be used as a guide for concerned government and non-government organizations for drought impacts mitigation activities in the Zone. Key words: Agricultural drought, GIS, NDVI, Remote Sensing, SPI, SPOT WRSI
Agricultural Drought Risk Area Identification Using Ndvi and Land Surface Temperature: a Case Study of East Arssi Zone, Ethiopia
(Addis Ababa University, 2019-05-05) Balcha, Gezahegn; Korme, Tesfaye (Professor)
Agriculture in the East Arssi Zone is the most vulnerable and sensitive sector that is seriously affected by the impact of climate variability and change, which is usually manifested through rainfall variability and recurrent drought.. Thus, in order to adapt and/or mitigate the impact of agricultural drought, agricultural drought risk area has to form one dimension of research to be done whereas the use of remote sensing and GIS techniques provides wide scope in drought risk area detection and mapping. Consequently, this study was conducted in East Arssi zone with the objective of assessing agricultural drought risk area identification and preparing agricultural drought risk area map using satellite data. To assess and examine spatiotemporal variation of seasonal agricultural drought patterns and severity, three drought indices namely, land surface temperature (LST), Standard precipitation index (SPI) and NDVI anomaly are applied. A time series MODIS NDVI AND LST satellite data for the years 2001- 2016 were utilized as input data for the indices while Meteorological data was used to validate the strength of indices in explaining the impact of agricultural drought. The result derived from indices for the study period has shown that the edge of rift valley and low land of Arssi continues mountain have been affected by severe drought, with observed spatial difference in severity level within East Arssi zone. However, the severity level was higher in 2009 and 2016 cropping seasons whereas 2015 being the most severe of all. In order to evaluate the strength of the indices for expressing the existence of agricultural drought, simple regression analysis of indices results with rain fall and NDVI, LST and SPI and NDVI and LST have been computed and can be a good indicator for occurrence of agricultural drought. Agricultural risk map of East Arssi zone was produced by integrating the three drought indices. The result indicates that East Arssi zone is classified into slight, severe and no drought agricultural drought risk area covering 22, 41.5 and 63.50 percent of the total geographical area respectively. Thus, this agricultural drought risk mapping can be useful to guide decision-making process in drought monitoring and to reduce the risk of drought on agricultural production and productivity.
Agricutltural Drought Assessment Using Remote Sensing and Gis Techinques
(Addis Ababa Universty, 2010-06) Legesse, Gizachew; Suryabhagavan, K.V. (PhD)
Climate has always been a dynamic entity affecting natural systems through the consequence of its variability and change. Agriculture is the most vulnerable and sensitive sector that is seriously affected by the impact of climate variability and change, which is usually manifested through rainfall variability and recurrent drought. In dryland semiarid areas of Ethiopia, including large part of East Shewa zone, agricultural drought and crop failure have been common, and farmers inhabiting the area experience extreme temporal and spatial variability of rainfall in cropping season with frequent and longer dry spells. This makes them vulnerable to the risk of agricultural drought. Thus, in order to adapt and/or mitigate the impact of agricultural drought, agricultural drought assessment has to form one dimension of research to be done whereas the use of remote sensing and GIS techniques provides wide scope in drought risk detection and mapping. Consequently, this study was conducted in East Shewa zone with the objective of assessing agricultural drought risk and preparing agricultural drought risk zone map using satellite data. To assess and examine spatiotemporal variation of seasonal agricultural drought patterns and severity, three drought indices namely, Water requirement satisfaction index (WRSI), Standard precipitation index (SPI) and NDVI anomaly are applied. A time series advanced very high resolution radiometer (AVHRR) NDVI and rainfall estimate (REF) satellite data for the years 1996- 2008 were utilized as input data for the indices while grain yield data was used to validate the strength of indices in explaining the impact of agricultural drought. The result derived from indices for the study period has shown that the 2000 to 2005 cropping seasons experienced enhanced agricultural drought with observed spatial difference in severity level within East Shewa zone. However, the severity level was higher in 2000 and 2002 cropping seasons whereas 2002 being the most severe of all. The impact of agricultural drought on crop production was measured through estimation of yield reduction. Compared to other cropping seasons of the analysis period, yield reduction for the years 2000 to 2005 was also higher in the East Shewa zone. Similarly, the year 2002 had highest reduction followed by that of the year 2000. Generally it is revealed that index results are in agreement with results of yield reduction depicting that yield reduction is largely attributed to agricultural drought. In order to evaluate the strength of the indices for expressing the existence of agricultural drought, simple regression analysis of indices results with total grain yield was computed. The result revealed that WRSI, SPI and NDVI anomaly express 76, 64 and 54 percent of variability of the grain yield in that order. Thus, WRSI can be a good indicator for occurrence of agricultural drought. Agricultural risk map of East Shewa zone was produced by integrating the drought frequency maps derived from the three drought indices in order to guide future prioritization of adaptation and mitigation options for agricultural drought prone areas. The result indicates that East Shewa zone is classified into slight, moderate and severe agricultural drought risk zone covering 17.18, 41.32 and 42.50 percent of the total geographical area respectively. Thus, this agricultural drought risk mapping can be useful to guide decision making process in drought monitoring and to reduce the risk of drought on agricultural production and productivity. Key words: Agricultural drought, GIS, NDVI, Remote Sensing, SPI, WRSI
Alleonathy in some Ethiopian Grasses.
(Addis Ababa University, 1982-06) Medhanie, Gebrehiwot; B. G. Egziabher, Dr . Tewolde
I nvestigation fo r possible chemi cal interactions among some of the common grass species that graw in and around Addis Ababa
Analysing the Relationship of Climate Change and Vegetation Cover Change Over the Last three Decades in Case of Chilimo Forest West Shewa Ethiopia
(Addis Ababa University, 2021-09-28) Negesa, Ajema; Kassawmar, Tibebu (PhD)
This study was conducted to investigate the relationship of climate change (described in terms of rainfall and temperature) with vegetation cover in Chilimo Forest, over the last three decades from 1990 to 2020. Multi-temporal Landsat imageries of 1990, 2000, 2010 and 2020, Climate Hazard group InfraRed Temperature with Stations (CHIRTS) and Climate Hazard group InfraRed Rainfall with Stations (CHIRPS) were used for this study. Field data and google earth were used to verify remote sensing data. In order to prepare LULC map of the study area support vector machine classification was applied. Accordingly, Pearson correlation coefficient was computed to analyses and quantify the relationship of rainfall and temperature with forest cover, shrubland, grassland and wetland. Mann-Kendall trend test was used to analysis non-parametric trend analysis for rainfall of 1990 to 2020 and temperature of 1990 to 2016. The result examined that there was 6599.16ha (29.43%), 6059.90ha (27.03), 6185.25ha (27.59%) and 5671.37ha (25.29%) of forestland, 1333.98ha (5.95%), 1693.35ha (7.55%), 1028.52ha (4.59%) and 1189.35ha (5.3) of shrubland, 953.31ha (4.25%), 850.89ha (3.79%), 736.23ha (3.28%) and 527.58ha (2.35%) of grassland and 66.78ha (0.3%), 63.09ha (0.28%), 41.22ha (0.18%), and 20.16ha (0.09%) of wetland coverage in 1990, 2000, 2010 and 2020, respectively. Additionally, the result exhibited that natural high forest, shrubland, grassland, wetland and bare land were declined by 2.7%, 0.64%, 1.9%, 0.2%, and 2.21% over the study area from 1990 to 2020. However, the result showed crop land was increased by value of 3.77%, 5.38%, and 1.59% consequently over the study period. Moreover, trend analysis result exhibited that mean, minimum, and maximum dry season and wet season mean and minimum temperature was increased in the study area. The Sen’s slope shows mean, minimum and maximum dry season temperature trend analysis result revealed increasing trend with 0.028 oC yr.-1, 0.036 oC yr.-1 and 0.031 oC yr.-1 respectively while wet season maximum temperature analysis result indicated decreasing trend by 0.016 oC yr.-1 from 1990 to 2016. In contrast, trend analysis result of mean, minimum and maximum dry season rainfall shown decreasing trend with factor of 2.075, 0.067 and 3.52 while annual rainfall trend analysis result examined decreasing and increasing trend from 1990 to 2020. Mann-Kendall trend test analysis for wet and dry season temperature and annual rainfall result was shown increasing trend. Whereas, dry season rainfall Mann-Kendall trend test analysis result shows increasing decreasing trend. Hence, coefficient of determination (R2) for forest cover, shrubland, grassland and wetland with annual and dry season rainfall result exhibited that R2 = 0 .61, R2 = 0 .57, R2 = 0 .95, R2 = 0 .62 and R2 = 0 .98, R2 = 0 .01, R2 = 0 .73, R2 = 0 .28, respectively. Besides, the result examines LULC of the study area was gradually changing for the last three decades since 1990. From the findings of the result there was variability of annual and dry season rainfall as well as wet and dry season temperature over the study area. Based on this finding’s vegetation cover were influenced by the effect of rainfall and temperature change which examined in western, north-eastern and central part of the study area. The consequence of examined land-cover change as well as variability of rainfall and temperature cause land degradation, deforestation and loss of forest resource. Indeed, implementing local level land-use planning and community based natural resource management implementation system is recommended to monitor, conserve and rehabilitate vegetation cover.
Analysis and Mapping of Soil Salinity levels in Metehara Sugarcane Estate Irrigation Farm using Different Models
(Addis Ababa Universty, 2009-07) Mekeberiaw, Afework; Suryabhagavan, K.V. (PhD)
This thesis deals with the analysis and mapping of soil salinity levels in Metehara sugarcane estate irrigation farm. An attempt was made to identify salt affected areas by visual interpretation using both true and false colour composite. From the supervised classification, 726 ha area was mapped as highly saline. However, the result obtained from NDSI was not only in area-wise, but also the level of salinity as highly saline, moderately and slightly saline, determined based on the reflectance value. Out of the total area, 6% was mapped as highly saline. A regression analysis between EC values of small areas confined only in Metehara Sugarcane estate and the corresponding reflectance value in the NDSI image offer a polynomial relation of order two. The empirical model that obtained from the regression analysis was used to derive a salinity map and estimate EC level. The spatial distribution of salt affected area derived from NDSI and model were of similar pattern but of different extent. In overlay salinity model, four classes have been identified with varying degree of salinity. The class of highly saline soils was found in the areas underlained by the lacustrine Sediments and shallow ground water level. It is evident that the areas highly vulnerable to salinization greatly related to the ground water level that normally occurred on the lacustrine sediment near to lake Beseka. The validation of the two models has been carried out by the existing EC values referenced to the same locations by making linear correlation. The correlation shows that overlay salinity model to be a better indicator of soil salinity than empirical model in the study area. Since empirical model detects only the salts on the surface of the soil and gives a poor idea about the conditions below surface, the overlay salinity model indicates the condition and existence of salt in the entire soil section between the surface and root zone. Then overlay analysis between salt affected areas and canal, drainage, water table and soil was made to assess the spatial distribution as well as the relationship with these features. It was revealed that the spatial distribution was not highly influenced by the features considered except water table. Key words: EC, NDSI, Soil salinity, Empirical Model, Overlay Salinity Model
Analysis Models of the Emptying Curves of five Selected Springs in Addis Ababa
(Addis Ababa Universty, 2007-07) Waltenigus Solomon; Alemayehu Tamiru (PhD)
The use of springs as a community water supply source in Addis Ababa dates back to the very early times of the establishment of the city. Other surface and ground water sources (dams and water wells) have also been constructed in its later development stage. No matter how big the newly developed sources are, it is true that spring sources are still in use. This justifies the importance of these sources as a means of potable water supply and invites for further detail investigations. Identification of springs with sustainable flow has been a pre requisite prior to construction. Analytical flow modeling of springs with has a lot to provide in answering this question as it helps to understand the flow and storage conditions of a spring source. In this study an attempt was made to analyze the emptying curves of six springs in Addis Ababa of which collected data have permitted the analysis of five of them. The analysis is based on monthly discharge monitoring of the springs for one hydrologic year. Water sampling has also been conducted from each spring for the determination of seasonal water quality changes. Recession curves were identified from the plot of the monthly spring discharge, from which flow and storage parameters were calculated. The main parameters of the sources have been estimated using the formula developed by Mangin (1970). From the analysis of the curves, it was possible to extract information on the contribution of rainfall to the spring discharge, storage conditions of the spring reservoir, the recharge conditions (rate of recharge) and the current reserve for sustainable flow. The method is applicable even to very small discharge springs. This has been considered as a means of identification of sustainable springs prior to construction.
Analysis of Biomass Degradation as an Indicator of Environmental Challenge of Bilate Watershed Using Gis Techniques
(Addis Ababa Universty, 2007-07) Sendabo, Degelo; Legesse, Dagnachew (PhD)
Advancement in spatial data processing especially using GIS techniques has been playing an important role in different applications. Multiple source spatial and non-spatial data can be processed for the analysis of spatiotemporal conditions of a given area. Having such an approach in mind the Bilate Watershed Biomass is analysed using multi-temporal Landsat images acquired in 1973, 1986 and 2001. Such data are processesed using digital image processing techniques including NDVI and Tasselled Cap analysis. Besides, different vector data are extracted from the images as well as other topographic and thematic maps. Land use land cover of the watershed is interpreted and based on that the level of biomass degradation is analysed. Using the integrated spatial information, decision support system has been applied for the identification of priority areas to be conserved due to their sever damage. The study identified major causes and effects of biomass degradation of the watershed. Key Word: Remote Sensing, GIS, Biomass, Environment, Degradation, decision making, conservation multitemporal, multispectral, land use, land cover.
Analysis of Human Deaths by Road Traffic Accident in Oromia Region, Ethiopia
(Addis Ababa University, 2018-06-01) Abdissa, Merga; Tadesse, Mekonnen (Professer)
Globally, road traffic accidents are leading causes of death among young people in general, and the main cause of death among those aged 15–29 years, in particular. In Ethiopia, the average number of road traffic injuries has been increasing from year to year, where Oromia regional State is the major contributor of the total fatalities occurred. The aim of this study is to identify the major factors determining the number of human death by road traffic accident in Oromia Regional State of Ethiopia using an appropriate count regression model based on data obtained from the Oromia Police Commission Bureau that have been recorded on daily basis during July 8, 2016 - July 7, 2017. The descriptive result showed that 2,712 out of 3,900 of the accidents were not fatal accidents. All formal statistical tests indicated that the data are overdispersed and that there are excess zeros. Among families of count models, the hurdle Poisson (HP) model was found to be the most appropriate to the dataset. The results of hurdle Poisson regression model showed that age of driver, experience of driver, type of vehicle, vehicle service, road condition, time of accident, location of accident, environment of accident, type of accident and accident cause were significant factors influencing the number of human death per accident in Oromia regional state of Ethiopia.
Analysis of Inter-Basin Groundwater Flow System Using Hydrogeochemical and Isotope Hydrology (Δ2h Andδ18o) Between Blue Nile and Awash Basins, the Case of Gerado and Borkena River Catchments
(Addis Ababa University, 2020-09-09) Ebrahim, Sadam; Azagegn, Tilahun (PhD)
Hydrochemistry and environmental isotope techniques has been used to analyze inter basin groundwater flow and hydrodynamic system between Gerado and Borkena River catchments located at the southwestern block of the Afar depression where it occupies parts of the northern plateau in the northwestern part, western Afar marginal area and associated Graben. The sratigraphy of the area is characterizes by volcanic episodes were by the extrusion of flood basalts, with interbeds of pyroclastic rocks of rhyolitic or less commonly trachytic compositions, particularly at upper stratigraphic levels and seismically active right stepping N-S trending step system of discontinuous graben that are tens of kilometers long and 5–15 km wide which follow the curving N-S trend of the western Afar margins. Lithostructurally, Ashange basalt sequence is strongly faulted and tilted by 20° to 30° towards east. The weathering and jointing with the inclined contact is a favorable condition for ground-water flow from highly elevated plateau to the marginal graben. Boreholes and spring in Gerado catchment are characterized mostly by low TDS (< 500 mg/l) and Ca-Mg-HCO3 water type. While the Borkena catchment show a complex groundwater type and variation in TDS (500- 938 mg/l) Based on its flow pattern. The water types in Borkena catchment generally dominated by Na and Ca cations. Based on inverse Geochemical Modeling and ionic ratio calculations dominant reaction happened on the flow paths of Groundwater is likely to be cation exchange which Na is Exchanging Ca and dissolution of silicate minerals. Most of the groundwater samples from Gerado and Borkena catchments have relatively depleted isotopic signature of 18O and D from -2.28 to -6.83 and -2.5 to -7.8 respectively. Isotopically depleted springs found in the adjacent areas of Borkena Catchment while most of the springs found in the Gerado catchment are fall in a line of local Meteoric water. Spring patterns suggest there is an inter-basin groundwater flow between the catchment. The springs have preferential alignment in emerging with a considerable discharge which support inter-basin groundwater flow.
Analysis of Land and Vegetation Cover Dynamics Using Remote Sensing & Gis Techiniques, A Case Study of Nechisar National Park
(Addis Ababa Universty, 2008-02) Nigussie, Asaye; Woldu, Zerihun (Professor)
The research aims to analyze the trend of land and vegetation cover dynamics over the period from 1976, 1986 2000 and 2007 thus examine the conservation status of the area and generate up-to-date land cover map. Information is extracted from various Satellite images of multidated Landsat, ASTER and MODIS images. The Landsat images are the basic remote sensing data to generate the thematic maps which are further analyzed to show the cover dynamics in the park for 24years. All data s from the satellite images are processesed and analyzed using digital image processing techniques. Besides, different vector data are extracted from the images as well as other thematic maps. MODIS-NDVI images are analyzed for the different land cover classes and each vegetation cover seasonal response is compared for the year 2000 and 2005. The land cover classes identified in the study area from 1976, 1986, 2000 and 2007 are water body, riparian and ground water (GW) forest, wood land, dense bush land, bushy shrubbed grass land, open grass land, degraded grass land, cultivated land, swamp vegetation and bare land. Rate of land cover change and fragmentation of habitat were discussed for the different land cover classes. Rate of land cover change, fragmentation index and land cover conversion matrix clearly shows the dynamics of the different cover classes has happened for the past decades and generally the park conservation status is found to be poor. Bush encroachment in the study area is a major challenge to the park particularly for the grass land and overgrazing on the Nechisar plain has caused expansion of invasive plants erosion and land degradation. The community livelihood dependency both in the rural and urban setting is concluded and discussed as a challenge to the park from biodiversity conservation point of view. Key Words: Land cover dynamics, National park, Vegetation cover, Remote sensing and GIS, Habitat fragmentation, degradation, biodiversity conservation
Analysis of Mine Call Factor at Meli Gold Mine (Ezana): Implementing an Ore Reconciliation System Considering Key Performance Indicators
(Addis Ababa University, 2020-06-03) Medhane, Tesfaye; Tadesse, Solomon (Professor)
The study area is located in the promising geological region, the ANS, where the first gold mining started in human history which also hosts the VMS deposit that yields multiple metals from single ore like Au, Cu, and Zn. Mining helps for sustainable development, however, involves high levels of complexity and uncertainty which require huge capital investment and risk. The most profitable way to exploit a mineral deposit requires continuous evaluation and planning. One practical method is to compare what was planned and what is achieved using MCF. It is the ratio, expressed as a percentage, of the gold called for to the gold accounted for. If everything went well, the comparison of what the mine delivered to the plant and what the plant received and processed must be as close as possible equal or an MCF of approximately 100%, a situation that is impossible in practice, hence an MCF of 85% was considered reasonable for shortfalls as per different practices in different mining operation. Using additional data and study, this case study will help to draw a national standard in the MCF acceptable values. The design capacity of the plant is 35 tonnes per hour. Considering the designed plant schedule, the crusher has a capacity of 12,500 tonnes per month crushing. The actual total crushed tonne is 175,742, with an average of 5,325 tonnes per month. Considering the crusher plant design capacity plan, the achievement is 42.6%. The total reconciled total mined and hauled ore were 281,246 tonnes with an average monthly of 8,523 tonnes, indicating that the shortfall is not due to ore supply; instead, it linked to the process plant related to various factors, mainly frequent and extended shutdown of the mill due to many reasons which are not the scope of this research. With the assumption of a metal recovery of 90.6%, the assumed metal recovered is 25,565 ounces which contributes to an MCF of 85.9%. Though the operation is within the acceptable range of MCF values, it requires studying and addressing the shortfalls. The MCF suggests that gold losses averaged at 14.1%, which implies a 14.1% of the expected revenue was not realized and this translates into negative financial underperformance. Total ore reserve is estimated at 515,837t@4.81 Au g/t contained 79,748.38 Oz of gold; with the design 92% recovery, the expected gold recovered is 73,368.51 Oz. As at March 2020, the mine extracted 55% (281,246t) of the reserve mass, indicating a 45% (234,591t) tonnes still remain on the ground. The plant processed 62.5% of the tonnes hauled from ROM stockpile, which is only 34% of the total reserve in terms of tonnes.
Analysis of Physical Accessibility to Health Facility: a Case Study of North Shewa Zone, Amhara Regional State of Ethiopia
(Addis Ababa University, 2014-05-05) Fantaye, Yetnayet; Berhan, Getachew (PhD)
Population of Ethiopia is still facing higher rate of morbidity and mortality. Majority of population lives in rural areas where healthcare service is very poor. Physical accessibility to healthcare measures interms of travel time, and distance to the nearest health facilities from people‟s residential areas. From these measurement options, this study used traveling time to reach health facilities from patients home. The central aim of the study is to assess physical accessibility to health facility within an hour travel time both by walking and vehicles in North Shewa Zone. To achieve this objective the study depends on AccessMod 4.0 model and incorporates population, land use, road network, digital terrain model, location of health care facilities and travelling time scenarios. Population distribution data is prepared by interpolating population at kebele level. Land cover data for the study area is prepared from Landsat enhanced thematic mapper plus satellite images and classified into five land cover types by using supervised method of image classification. Classified land cover types are assigned traveling speed per hour in the traveling scenario table. Results obtained from the model provide hospitals serving about 72937(4%) and health centers 240,473(13%) out of the whole population in an hour travel time both by walking and vehicles, and covers 4,167 km2 and 704.91 km2 area, respectively. Hence, priority must be given to areas with higher health facility population ratio and areas where there are access limitations to these facilities within the defined scenario.
“Analysis of potential sanitary landfill waste disposal sites”; the case of Addis Ababa city
(Addis Ababa Universty, 2009-06) Maschal, Mekonnen; umer, Mohammed (PhD)
Urban population growth together with the development of new industries and commercial centres generate huge amount of solid waste daily. Like in many developing world cities a rapid population growth and high rural-urban migration posses many environmental challenges for the Addis Ababa city. One of these is dry waste management and disposal system. In adequate dry waste management has resulted in the accumulation of solid waste on open lands, in rivers, in drains and in the living area of many people, causing a nuisance and foul-smelling pools, environmental pollution through leaches from piles (water and soil pollution) and burning of waste (air pollution), clogging of drains, and the possible spread of diseases. This situation is believed to result in poor environmental conditions and an ever-present risk of epidemics, which in turn present a formidable threat to health and productivity. The present method of disposal is crude open dumping; hauling the wastes by truck, spreading and leveling by bulldozer and compacting by compactor bulldozer at the only one dumpsite ‘koshe’. The dumpsite is getting full; it is partly surrounded by residents and institutions and has no gas control. The gas generated from landfill causes spontaneous fire and air pollution. It contributes enormous amount of methane (green house gas) to the atmosphere. The site has low area capacity (25 ha), poor protection of ground water and surface water pollution. Now, for the time being, the environmental impact of this disposal sites on human beings, soil, air and water quality makes this issue a subject of many researchers in addressing the safe way disposal system. Proper disposal site selection of the waste is a challenging issue that must be addressed adequately. Land filling is one of the common methods used for waste disposal. GIS (Geospatial Information System) is a computerized tool for solving environmental problems. It can then be used to optimize the selection process of landfill site. Through various functionalities, GIS is able to provide a better understanding of the effects of the sites on the environment. The objectives of this project are to identify and evaluate the major earth related factors on landfill site selection, and to describe the methods for proper landfill location estimation. As a case study to the whole part of Addis Ababa city has been selected to evaluate the candidate locations. The data used included geologic condition (hydraulic conductivity), soil type distribution, underground water (depth), surface hydrology (rivers), topographic maps and geomorphology (slope), land use property and distance from the main road. The data are combined together using DRASTIC procedure on a commercial GIS software package to locate and visualize the selected site. The paper elaborates all the methodologies used, and the scientifically evaluated results. Finally, this project paper produced a more recommended suitable landfill sites map for Addis Ababa city. Also the project paper forwarded a scientifically analyzed recommendation for a previously proposed landfill and existing open dump site in the city
Analysis of Subsurface Contaminant Transport in Akaki Well Field and surrounding areas, Central Ethiopia
(Addis Ababa Universty, 2007-08) Gudissa, Leta; Asrat, Asfawossen (PhD)
The acute need for water in big cities like Addis Ababa calls for an integrated water resources development approach that considers the entailing environmental factors. This task becomes even more pressing as industrialization and development advances. In view of this, the current study aims to identify potential movement of pollutants in a wellfield, and specifically to identify the pathways of pollutants and their spatial movement in the aquifer. The study area, the Akaki well field and surrounding areas including the towns of Kality and Akaki, is located in the Awash drainage basin, southeast of the Addis Ababa city centre. The well field provides more than 30 % of the drinking water supply of Addis Ababa. A groundwater flow model was constructed to analyze contaminant transport in a fractured system. The model was then calibrated with both under steady state and transient state flow conditions, in order to prove that the model represents the actual conditions. Modeling tools have been eventually used to calculate path lines and travel times of contamination. This approach involved the introduction of particles at contaminant sources upstream of wells and at the well field it self, then identifying the path lines, and determining the spatial distribution of the contaminants through steady state flow field at initial step and finally through transient state flow field. The individual measured data for nearly 120 wells were interpolated using kriging method and each cell in the model was assigned its value. The well data base is obtained from AAWSA. The physical parameters are well organized; however, the Hydrochemical data are too old and does not indicate real sign of pollution. The results revealed that the flow lines intersect with the Akaki River in numerous places. Furthermore, the flow lines converge towards Akaki well field from all directions, implying that any contaminated water from the upper part of the aquifer will be pulled into the wells, indicating a high risk of vulnerability of the well field to pollution. The following recommendations are helpful in curbing the risks posed. Manufacturing activities having pollution potential must be limited in special areas sufficiently far from water supply wells; the chemical quality of groundwater must be monitored and Environmental policy must be implemented with particular emphasis for the protection zones around the well field. This study generated a model and recommendations that allows decision makers to establish a framework for regulating contaminants that are likely to pose risks to drinking water in the well-field.
Analysis on Terrain and Related Challenges in Defense Command Post Site Selection Using Web-Based Gis: a Case of Ada’a District, Eastern Showa Ethiopia
(Addis Ababa University, 2015-06-06) Akele, Menbere; Sendabo, Degelo (MR.); Asrat, Asfawossen (PhD)
The defense force keeps the sovereignty of the nation and responsibility to the operation of mission success at right time and place to control key terrain areas, to deliver logistics and to combat troops with accurate terrain information. But manually combining terrain information is tiresome, time taking, costy and results vary from expert to expert, therefore the analysis of terrain features for command post best site selection is one of the basic tasks from different military operations and the study provides decision makers and commanders to analyze the terrain visually using automated systems to obtain correct information about the terrain and evaluate the terrain in terms of military aspects. To understand the ground and achieve military goals, the basic sources of information for studying the terrain are topographic maps, aerial photographs, military sketches and sand model. This research paper identifies terrain features for defense command post site selection using RS and GIS techniques and customize and publish maps in web-GIS C4I system for decision makers or commanders. The command post suitable site selection is based on input data layers of elevation, slope, roads, land use land cover, soil types, geological and geomorphological features. The multi-attribute and multi-criteria evaluation methods (GIS with AHP) are used for factor analysis and aggregation. Multi factor analysis or weighted overlay analysis assigns more importance of some criteria over the others. The AHP principle can be used to aggregate the priority for all level of hierarchy structure and the method can be done using any GIS system having overlay capabilities, combine input layers and generate the output command post suitable map. The result showed that optimal sites clearly identified as a higher elevation weight equal to 39% influence is the most important criteria from others. The resulting maps of GIS – AHP indicates best result and suitable location for military command post in Ada’a district.
Application and Evaluation of LAMP Assay for Detection of Enterohemorrhagic Escherichia Coli (O157:H7)
(Addis Ababa University, 2019-02-03) Yinur, Degisew; Sisay, Tesfaye (PhD)
O157:H7 E. coli are one of the enterohemorrhagic E. coli strains which cause bloody diarrhea and hemorrhagic colitis as well as hemolytic uremic syndrome in humans. This pathogen has been implicated in the worldwide outbreak of food and water borne diseases. Cost effective, sensitive rapid time detection of this pathogen is beneficial. The objective of the current study was to design and evaluate LAMP diagnostic assay for detection of EHEC O157:H7. In this study, putative fimbria protein coding gene (Z3276) was used to design a loop mediated isothermal amplification (LAMP) assay for the rapid and specific detection of EHEC O157:H7. A total number of 40 pathogenic and non-diarrheic E. coli as well as non E. coli bacteria were used to evaluate the assay. The LAMP amplified DNA samples were visualized as turbid DNA with naked eye as well as using gel electrophoresis and staining. The assay performed with 100% sensitivity, 97.05 % specificity, as well as 97.5% efficiency. The assay was also 10 times more sensitive than the conventional PCR assay; sensitivity evaluation was done through serial dilution. Additionally, the two assay results showed very high agreement (k = 0.97) on detection of the studied isolates. However, faecal samples spiked with the bacteria (DNA extracted by crude lysate) were not successfully detected by both LAMP assay and PCR method.
Application of Geophysical Method for Delinatig Shallow and Deep Ground Water Flow System Along Ziway-Butajira and Meki-Midrekebd Traverses, Central Mer, and Thier Implication for Flouride Concentration
(Addis Ababa Universty, 2017-05) Ararso, Mandefro; Haile, Tigistu (Professor)
An integrated geophysical survey using Vertical Electrical Sounding (VES) and Audio Magneto Telluric (AMT) method was conducted to separate shallow and deep ground water flow systems and the role geological structure play in the movement of these waters from Rift Floor to Western Escarpment sectors, specifically through geophysical work along the Ziway-Butajira and Meki-MidreKebd traverses. These methods were selected for their resolution and ability to map the shallow to intermediate depth (VES) and the deeper (AMT) horizons in the subsurface. Geographically the Ziway-Butajira and Meki- Midrekebd areas lie in the Central Main Ethiopian Rift within Oromia and South Nations, Nationalities and Peoples Regional State in Ethiopia. The areas also lie on dominantly volcanic and lacustrine deposit terrain. The geophysical survey included twenty three (23) VES point using Schlumberger array with maximum half current electrodes AB/2 =750m and twenty seven (27) 2DAMT measuring points. These data were interpreted both qualitatively and quantitatively in order to infer the subsurface geoelectrical stratification of the area and hence the geology as well as the major geologic structures over the transects. It was also possible to extract information on the presence of groundwater bearing horizons in the subsurface including their location and depth. The qualitative analysis of VES data were performed by using apparent resistivity psuedodepth sections constructed for VES points oriented in a near collinear direction, while the qualitative interpretation of the 2D AMT data were also performed by using 2D MT geoelectric sections. For quantitative interpretation, the individual VES data were interpreted using the ResixIP and Win Resist modeling software to obtain the layer parameters beneath each VES and constructing the geoelectrical sections along selected survey lines. The interpretation of the VES during modeling was constrained by lithological logs from two nearby boreholes. The information from VES data and the borehole were also used to constrain the depth information in the 2D MT modeling which are conducted on four survey line. In general, the VES result revealed four to five main geoelectrical layers that differ in degree of weathering and fracturing, composition and depth of burial. The geoelctrical sections further enabled the identification of the depth to the aquifer along the survey line. On the other hand, the 2D AMT help to identify low resistivity zones and structures that extend to larger depth- which has easily mapped the subsurface to depths of about 1200 m. Finally the overall interpretation was done by integrating all the above result together with the topographic maps and bore hall information. As a result of these shallow and deep ground water systems and geological structures are identified. It is found that vertical and near vertical structures that extend to larger depth is mapped along the traverses showing that there is a flow of shallow groundwaters to the deeper horizons, with no major separation between the two groundwater systems. It has also been possible to delineate drilling sites for potential productive boreholes.

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