A. Tesfay, Mesele Hayelom Hailu, Filmon A Gebrerufael, M. Adaramola
In Ethiopia, like most developing countries, the majority of households depend on wood and charcoal as their cooking energy resources. This energy has a direct impact on the forest coverage and its emissions have significant health issues. Biogas technology has introduced to address these problems and reduce energy poverty in developing countries. However, the success of this technology depends on many factors such as technology appropriateness, available skill, proper introduction, and government support to create favorable financial incentives. The objective of this paper is to make an overview assessment of biogas development programs in Ethiopia, identify development barriers and provide suggestions to mitigate these barriers. The national and regional biogas program of Ethiopia has implemented to give energy for cooking and to some extent for lighting. However, it has shown limited success over the years. The National Biogas Programme of Ethiopia has shown an overall 50% achievement while the Tigray region registered 55% achievement. In addition, the owner of the biogas facility in Tigray reported a 57% functionality rate but the lowest satisfaction level of 15%. Generally, the region has shown relatively better performance in terms of dissemination and functionality but a low satisfaction rate due to technical limitation, unsteady input, and financial factors.
{"title":"Implementation and Status of Biogas Technology in Ethiopia- Case of Tigray Region","authors":"A. Tesfay, Mesele Hayelom Hailu, Filmon A Gebrerufael, M. Adaramola","doi":"10.4314/MEJS.V12I2.7","DOIUrl":"https://doi.org/10.4314/MEJS.V12I2.7","url":null,"abstract":"In Ethiopia, like most developing countries, the majority of households depend on wood and charcoal as their cooking energy resources. This energy has a direct impact on the forest coverage and its emissions have significant health issues. Biogas technology has introduced to address these problems and reduce energy poverty in developing countries. However, the success of this technology depends on many factors such as technology appropriateness, available skill, proper introduction, and government support to create favorable financial incentives. The objective of this paper is to make an overview assessment of biogas development programs in Ethiopia, identify development barriers and provide suggestions to mitigate these barriers. The national and regional biogas program of Ethiopia has implemented to give energy for cooking and to some extent for lighting. However, it has shown limited success over the years. The National Biogas Programme of Ethiopia has shown an overall 50% achievement while the Tigray region registered 55% achievement. In addition, the owner of the biogas facility in Tigray reported a 57% functionality rate but the lowest satisfaction level of 15%. Generally, the region has shown relatively better performance in terms of dissemination and functionality but a low satisfaction rate due to technical limitation, unsteady input, and financial factors.","PeriodicalId":18948,"journal":{"name":"Momona Ethiopian Journal of Science","volume":"12 1","pages":"257-273"},"PeriodicalIF":0.3,"publicationDate":"2021-05-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"46722904","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
The level of rational use of electricity consumption by households in Mozambique is very low. This paper assesses whether, with the implementation of education and awareness actions through the door-to-door method, is possible to change the consumption habits and rationalize residential electricity consumption in Maputo city, Mozambique. The data was collected through questionnaires, observations, and interviews related to the habits of electricity consumption, the use of electrical equipment, and consumption of household appliances. This was followed by awareness creation on the use of electricity. The results show that after the campaign, the level of knowledge of the measures of rational use of electricity by consumers was increased by 55.3%, the level of adoption of the measures learned was increased by 30.5% and the monthly household consumption was decreased by 16.8%. Household consumption depends on the electrical equipment, and replacement of at least one 60W incandescent lamp in each residence with a 15W fluorescent lamp could bring a significant reduction in energy consumption. For example, the annual consumption of each family can be reduced by 94KWh and 23GWh in the entire City. The low level of rational use of electricity in Maputo city is due to lack of knowledge of the measures and little adoption of the known measures, use of inefficient equipment, low availability of the efficient equipment in the local markets, high cost of efficient technologies, and houses that offer few opportunities for rationing. Rationing; Electricity consumers; Habits; Awareness; Maputo; Mozambique.
{"title":"Rationing of Electricity in Maputo City Residences through Education and Awareness Actions","authors":"N. A. Chapala","doi":"10.4314/MEJS.V12I2.3","DOIUrl":"https://doi.org/10.4314/MEJS.V12I2.3","url":null,"abstract":"The level of rational use of electricity consumption by households in Mozambique is very low. This paper assesses whether, with the implementation of education and awareness actions through the door-to-door method, is possible to change the consumption habits and rationalize residential electricity consumption in Maputo city, Mozambique. The data was collected through questionnaires, observations, and interviews related to the habits of electricity consumption, the use of electrical equipment, and consumption of household appliances. This was followed by awareness creation on the use of electricity. The results show that after the campaign, the level of knowledge of the measures of rational use of electricity by consumers was increased by 55.3%, the level of adoption of the measures learned was increased by 30.5% and the monthly household consumption was decreased by 16.8%. Household consumption depends on the electrical equipment, and replacement of at least one 60W incandescent lamp in each residence with a 15W fluorescent lamp could bring a significant reduction in energy consumption. For example, the annual consumption of each family can be reduced by 94KWh and 23GWh in the entire City. The low level of rational use of electricity in Maputo city is due to lack of knowledge of the measures and little adoption of the known measures, use of inefficient equipment, low availability of the efficient equipment in the local markets, high cost of efficient technologies, and houses that offer few opportunities for rationing. \u0000Rationing; Electricity consumers; Habits; Awareness; Maputo; Mozambique.","PeriodicalId":18948,"journal":{"name":"Momona Ethiopian Journal of Science","volume":"12 1","pages":"197-211"},"PeriodicalIF":0.3,"publicationDate":"2021-05-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"42558579","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Fana Filli, A. M. Mahmud, M. Bayray, Meseret Tesfay, P. Gebray
To meet sustainable development goals and address concerns on climate change, much of the world's energy demand is expected to be delivered from clean alternative energy sources. Small-scale wind turbines have proven to be applicable for off-grid electrification. The objective of this study is to present the details on the design and manufacture of a 1 kW wind turbine blade for specified conditions. Blade element moment theory is adopted in the design of the geometry of the blade. Accordingly, the aerodynamic analysis on NACA 64A410 airfoil resulted in a blade radius of 1.95m, an overall twist angle of 31°, and a gradually tapering chord length of 0.062m at the root and 0.247m at the tip of the blade. Then, the wind turbine blades are manufactured from fiberglass (mat350g), resin, catalyst, and gelcoat. Experimental results reveal the wind turbine blades started producing power at a cut-in wind speed of 3m/s. The maximum power achieved during the testing process was 900W at a hub wind velocity of 9m/s. This is lower than the expected 1000W theoretical power output due to not perfect workmanship in the manufacture of the wind turbine blades. This study will help in building local manufacturing facilities and enhance rural electrification through off-grid technologies.
{"title":"Design and Manufacture of 1kW Wind Turbine Blades","authors":"Fana Filli, A. M. Mahmud, M. Bayray, Meseret Tesfay, P. Gebray","doi":"10.4314/MEJS.V12I2.2","DOIUrl":"https://doi.org/10.4314/MEJS.V12I2.2","url":null,"abstract":"To meet sustainable development goals and address concerns on climate change, much of the world's energy demand is expected to be delivered from clean alternative energy sources. Small-scale wind turbines have proven to be applicable for off-grid electrification. The objective of this study is to present the details on the design and manufacture of a 1 kW wind turbine blade for specified conditions. Blade element moment theory is adopted in the design of the geometry of the blade. Accordingly, the aerodynamic analysis on NACA 64A410 airfoil resulted in a blade radius of 1.95m, an overall twist angle of 31°, and a gradually tapering chord length of 0.062m at the root and 0.247m at the tip of the blade. Then, the wind turbine blades are manufactured from fiberglass (mat350g), resin, catalyst, and gelcoat. Experimental results reveal the wind turbine blades started producing power at a cut-in wind speed of 3m/s. The maximum power achieved during the testing process was 900W at a hub wind velocity of 9m/s. This is lower than the expected 1000W theoretical power output due to not perfect workmanship in the manufacture of the wind turbine blades. This study will help in building local manufacturing facilities and enhance rural electrification through off-grid technologies.","PeriodicalId":18948,"journal":{"name":"Momona Ethiopian Journal of Science","volume":"12 1","pages":"173-196"},"PeriodicalIF":0.3,"publicationDate":"2021-05-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"41936287","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
In this paper, the performance of Permanent Magnet Synchronous Generator (PMSG) -based Variable Speed Wind Turbine Generator (WTG) at Adama Wind Farm I (WTG), connected to a grid is studied. To study the performance of the WTG, both machine and grid side converters are modeled and analyzed very well. On the machine side, maximum power point tracking (MPPT) for maximum energy extraction is done using the direct speed control (DSC) technique, which is linked with the optimal tip speed ratio for each wind speed value considered. On the grid side, dc-link voltage and reactive power flow to the grid are controlled. For this purpose, first, the simulation model of the system is prepared in MATLAB Simulink considering the dynamic mathematical model of the PMSG, and Wind Turbine Aerodynamic model using the user-defined function blocks. Then, the PI regulators designed for direct speed, torque (current) control, and dc-link voltage are employed in the model. Moreover, to study and analyze the behavior of the system in a variable speed operation, a wind speed starting from cut-in wind speed (3m/s) to the rated wind speed (11m/s) is applied in 4s. The simulation result of the existing system model shows that the actual values of performance variables correspond well with the analytical values of the system. In addition, the chosen control algorithms applied in the control system of the generator-side converter are hence verified.
{"title":"Dynamic Modeling and Performance Analysis of PMSG- based Variable Speed WTG: Case Study of Adama Wind Farm I, Ethiopia","authors":"Z. Muluneh, Gebremichael Teame","doi":"10.4314/MEJS.V12I2.1","DOIUrl":"https://doi.org/10.4314/MEJS.V12I2.1","url":null,"abstract":"In this paper, the performance of Permanent Magnet Synchronous Generator (PMSG) -based Variable Speed Wind Turbine Generator (WTG) at Adama Wind Farm I (WTG), connected to a grid is studied. To study the performance of the WTG, both machine and grid side converters are modeled and analyzed very well. On the machine side, maximum power point tracking (MPPT) for maximum energy extraction is done using the direct speed control (DSC) technique, which is linked with the optimal tip speed ratio for each wind speed value considered. On the grid side, dc-link voltage and reactive power flow to the grid are controlled. For this purpose, first, the simulation model of the system is prepared in MATLAB Simulink considering the dynamic mathematical model of the PMSG, and Wind Turbine Aerodynamic model using the user-defined function blocks. Then, the PI regulators designed for direct speed, torque (current) control, and dc-link voltage are employed in the model. Moreover, to study and analyze the behavior of the system in a variable speed operation, a wind speed starting from cut-in wind speed (3m/s) to the rated wind speed (11m/s) is applied in 4s. The simulation result of the existing system model shows that the actual values of performance variables correspond well with the analytical values of the system. In addition, the chosen control algorithms applied in the control system of the generator-side converter are hence verified.","PeriodicalId":18948,"journal":{"name":"Momona Ethiopian Journal of Science","volume":"12 1","pages":"155-172"},"PeriodicalIF":0.3,"publicationDate":"2021-05-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"70567031","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Wind flow over the airfoil surface is adversely affected by the differences between the design and ambient values of a dimensionless quantity called Reynolds number. Wind turbine designed for high Reynolds Number shows lower maximum power performance when installed in low-speed wind regime. Tanzanian experience shows that some imported modern wind turbines depict lower power performance compared to the drag-type locally manufactured wind turbines. The most probable reason is the difference between design and local ambient Reynolds numbers. The turbine design parameters have their properties restricted to the range of Reynolds numbers for which the turbine was designed for. When a wind turbine designed for a certain range of Reynolds numbers is made to operate in the Reynolds number out of that range, it behaves differently from the embodied design specifications. The small wind turbine of higher Reynolds number will suffer low lift forces with probably occasional stalls.
{"title":"Effect of Ambient Reynolds Number on Small Wind Turbine Subjected to Low Wind Speed Conditions","authors":"Joel Mbwiga, C. Kimambo, J. Kihedu","doi":"10.4314/MEJS.V12I2.5","DOIUrl":"https://doi.org/10.4314/MEJS.V12I2.5","url":null,"abstract":"Wind flow over the airfoil surface is adversely affected by the differences between the design and ambient values of a dimensionless quantity called Reynolds number. Wind turbine designed for high Reynolds Number shows lower maximum power performance when installed in low-speed wind regime. Tanzanian experience shows that some imported modern wind turbines depict lower power performance compared to the drag-type locally manufactured wind turbines. The most probable reason is the difference between design and local ambient Reynolds numbers. The turbine design parameters have their properties restricted to the range of Reynolds numbers for which the turbine was designed for. When a wind turbine designed for a certain range of Reynolds numbers is made to operate in the Reynolds number out of that range, it behaves differently from the embodied design specifications. The small wind turbine of higher Reynolds number will suffer low lift forces with probably occasional stalls.","PeriodicalId":18948,"journal":{"name":"Momona Ethiopian Journal of Science","volume":"12 1","pages":"223-231"},"PeriodicalIF":0.3,"publicationDate":"2021-05-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"42403239","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Natural convection indirect type solar dryer integrated with reflectors that can be used for drying fruits and vegetables was designed, constructed, and evaluated. The study mainly tried to improve the performance of a prototype natural convection indirect solar dryer. The solar dryer was integrated with reflectors and its thermal performance was experimentally analyzed and results were compared with the same dryer without reflectors. The experiments conducted included a no-load test to determine the stagnation temperature that can be reached and drying tests using tomato slices. During the drying test, moisture content at the initial and final stages was measured using a moisture balance instrument. The mass of the tomato slices was measured every two hours to find the drying efficiency. Temperatures were measured using thermocouples located at the absorber plate and at the trays inside the drying cabinet. Solar radiation was also measured using a pyranometer located near the dryer. During no load experiments, the maximum temperature reached the collector was around 98oC for the dryer without reflectors. The maximum temperature was improved to around 154oC during the test with reflectors. Similar temperature improvement was obtained during the drying tests as well. Due to the improvement in the temperature in the collector, the drying rate was also improved by 8% for 10 kg and 14% for 5 kg load. The experimental results indicate that the dryer performance was improved when the reflectors were added.
{"title":"Performance Enhancement of Natural Convection Indirect Solar Dryer by Integrating Reflectors","authors":"Hailay Teklu, M. Bayray, Dawit Abay, M. Kalamegam","doi":"10.4314/MEJS.V12I2.4","DOIUrl":"https://doi.org/10.4314/MEJS.V12I2.4","url":null,"abstract":"Natural convection indirect type solar dryer integrated with reflectors that can be used for drying fruits and vegetables was designed, constructed, and evaluated. The study mainly tried to improve the performance of a prototype natural convection indirect solar dryer. The solar dryer was integrated with reflectors and its thermal performance was experimentally analyzed and results were compared with the same dryer without reflectors. The experiments conducted included a no-load test to determine the stagnation temperature that can be reached and drying tests using tomato slices. During the drying test, moisture content at the initial and final stages was measured using a moisture balance instrument. The mass of the tomato slices was measured every two hours to find the drying efficiency. Temperatures were measured using thermocouples located at the absorber plate and at the trays inside the drying cabinet. Solar radiation was also measured using a pyranometer located near the dryer. During no load experiments, the maximum temperature reached the collector was around 98oC for the dryer without reflectors. The maximum temperature was improved to around 154oC during the test with reflectors. Similar temperature improvement was obtained during the drying tests as well. Due to the improvement in the temperature in the collector, the drying rate was also improved by 8% for 10 kg and 14% for 5 kg load. The experimental results indicate that the dryer performance was improved when the reflectors were added.","PeriodicalId":18948,"journal":{"name":"Momona Ethiopian Journal of Science","volume":"12 1","pages":"212-222"},"PeriodicalIF":0.3,"publicationDate":"2021-05-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"44238962","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
The rapid economic growth and urbanization in Ethiopia have led to extensive construction activities in major cities. Construction activities have known to generate large quantities of wastes that pose serious environmental problems. This paper presents the challenges of construction waste management practices in Mekelle city and explores appropriate measures to address the issues in a more sustainable way. Field observation, questionnaire survey, interviewing of public sector officials at different levels was conducted to identify the source and management options of construction waste in the city. The findings showed that the majority of survey participants felt that their firms have taken various measures to manage construction waste. It was revealed that 40% of the respondents exercise illegal dumping as a common method of waste management, which is closely followed by reuse and recycling. It is evident that over 75% of the construction- generated has potential for recycling and reuse as backfilling and base for roads and buildings. The increase in the number of illegal dumping sites in the city represents the failure to properly control and implement effective construction waste management. It was suggested that sustainable solution for construction waste management at local level depends on increasing awareness and promoting reusing and recycling of construction waste.
{"title":"Assessment of Construction Waste Management Practice in Mekelle, northern Ethiopia: Challenges and Opportunities","authors":"T. Alemayehu, A. Osman, H. Goitom","doi":"10.4314/mejs.v13i1.10","DOIUrl":"https://doi.org/10.4314/mejs.v13i1.10","url":null,"abstract":"The rapid economic growth and urbanization in Ethiopia have led to extensive construction activities in major cities. Construction activities have known to generate large quantities of wastes that pose serious environmental problems. This paper presents the challenges of construction waste management practices in Mekelle city and explores appropriate measures to address the issues in a more sustainable way. Field observation, questionnaire survey, interviewing of public sector officials at different levels was conducted to identify the source and management options of construction waste in the city. The findings showed that the majority of survey participants felt that their firms have taken various measures to manage construction waste. It was revealed that 40% of the respondents exercise illegal dumping as a common method of waste management, which is closely followed by reuse and recycling. It is evident that over 75% of the construction- generated has potential for recycling and reuse as backfilling and base for roads and buildings. The increase in the number of illegal dumping sites in the city represents the failure to properly control and implement effective construction waste management. It was suggested that sustainable solution for construction waste management at local level depends on increasing awareness and promoting reusing and recycling of construction waste.","PeriodicalId":18948,"journal":{"name":"Momona Ethiopian Journal of Science","volume":"1 1","pages":""},"PeriodicalIF":0.3,"publicationDate":"2021-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"70567111","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Roads constructed along the mountainous terrains of Ethiopia are susceptible to landslides mostly during rainy season. Mekelle – Abi Adi road is one of the economically important road corridors that connects many towns with Mekelle city. However, the asphalt road segment is heavily affected by quasi-translational type of landslide which hinders traffic flow of the area. Vertical electrical sounding (VES) method was applied to investigate subsurface geology of the road failure along Mekelle – Abi-Adi asphalt road, northern Ethiopia. The geo-electric section result revealed that the shallow subsurface geology of the site is characterized by four distinct geological formations, from top to bottom are: shale, shale-limestone intercalation, limestone and shale-gypsum units. The subgrade of the failed road section is shale unit which is overlain by jointed sandstone unit. The sandstone unit serves as a recharge zone to the bottom shale layer by percolating water via sub-base fill materials which in turn blocks vertical percolation and promote seepage force to the overlying soil mass. Hence, the road failure in the study area seems to be caused due to the development of pore water pressure in the shale layer which soaked water during heavy rainfall. The recommended remedial method for the road failure is re-designing of the affected route from chainage 48 km+850 m to 49 km+250 m towards the northwest of the study area and excavates the top 6 m shale unit.
{"title":"Vertical Electrical Sounding (VES) investigation for road failure along Mekelle – Abi-Adi road segment, northern Ethiopia","authors":"G. Mebrahtu, Solomun Atsbaha, Berihu Abadi Berhe","doi":"10.4314/mejs.v13i1.7","DOIUrl":"https://doi.org/10.4314/mejs.v13i1.7","url":null,"abstract":"Roads constructed along the mountainous terrains of Ethiopia are susceptible to landslides mostly during rainy season. Mekelle – Abi Adi road is one of the economically important road corridors that connects many towns with Mekelle city. However, the asphalt road segment is heavily affected by quasi-translational type of landslide which hinders traffic flow of the area. Vertical electrical sounding (VES) method was applied to investigate subsurface geology of the road failure along Mekelle – Abi-Adi asphalt road, northern Ethiopia. The geo-electric section result revealed that the shallow subsurface geology of the site is characterized by four distinct geological formations, from top to bottom are: shale, shale-limestone intercalation, limestone and shale-gypsum units. The subgrade of the failed road section is shale unit which is overlain by jointed sandstone unit. The sandstone unit serves as a recharge zone to the bottom shale layer by percolating water via sub-base fill materials which in turn blocks vertical percolation and promote seepage force to the overlying soil mass. Hence, the road failure in the study area seems to be caused due to the development of pore water pressure in the shale layer which soaked water during heavy rainfall. The recommended remedial method for the road failure is re-designing of the affected route from chainage 48 km+850 m to 49 km+250 m towards the northwest of the study area and excavates the top 6 m shale unit.","PeriodicalId":18948,"journal":{"name":"Momona Ethiopian Journal of Science","volume":"1 1","pages":""},"PeriodicalIF":0.3,"publicationDate":"2021-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"70566895","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Morphometric analysis is the measurement and mathematical analysis of the configuration of the surface, shape, and dimension of landforms. The objective of this study is to characterize the Aynalem and Illala streams using the morphometric parameter. The topographic map at a scale of 1:50,000 taken from the Ethiopian National Mapping Agency was used to characterize the linear and areal aspects. ASTER Digital Elevation Model with 10m resolution was used to characterize the relief aspect. The Arc GIS 10.4.1 was used during the morphometric analysis. The analysis result of the streams is summarized based on the linear, areal, and relief aspects. The area is characterized by a dendritic drainage pattern which is characteristics of massive hard rock terrain. The Aynalem and Illala streams are 4th and 5th order streams. Considering the number of streams in the Aynalem (75.81%) and Illala (74.66%) is composed of first-order streams that indicate a flashy flood and the mean bifurcation value of Aynalem (6.8) and Illala (4.7) shows that the Aynalem area is more structurally affected than Illala but both show less stream integration. The analysis of areal aspects such as elongation ratio, circularity ratio, and form factor has indicated that both streams are characterized as elongated streams, this implies that both streams are flowing in heterogeneous rock material, presences of structural effect, and slow runoff discharge. The other areal aspect such as drainage density, stream frequency, infiltration number, and length of overland flow all show smaller values in both streams. This implies that the streams are characterized by a relatively permeable rock material with a higher infiltration capacity. The relief aspect of the Aynalem and Illala was also analyzed using basin relief, relief ratio, ruggedness number, hypsometric curves, and Hypsometric integral. The streams are characterized by a lower relief ratio and ruggedness number which implies a relatively flat slope and lower relief. The hypsometric curves and the Hypsometric Integral of the streams indicate that the Aynalem and Illala are at the maturity stage. This shows the area is characterized by higher erosion but less affected by recent structures. Based on the morphometric parameter analysis result it is possible to conclude that the stream development is dependent on the topography and geology of the study area and both streams show similar morphometric character.
{"title":"Quantitative Geomorphological Parameters Analysis for the Aynalem- Illala Streams, Tigray, Northern Ethiopia","authors":"Fethangest Woldemariyam Tesema, Gebrerufael Hailu Kahsay, Berihu Abadi Berhe","doi":"10.4314/mejs.v13i1.4","DOIUrl":"https://doi.org/10.4314/mejs.v13i1.4","url":null,"abstract":"Morphometric analysis is the measurement and mathematical analysis of the configuration of the surface, shape, and dimension of landforms. The objective of this study is to characterize the Aynalem and Illala streams using the morphometric parameter. The topographic map at a scale of 1:50,000 taken from the Ethiopian National Mapping Agency was used to characterize the linear and areal aspects. ASTER Digital Elevation Model with 10m resolution was used to characterize the relief aspect. The Arc GIS 10.4.1 was used during the morphometric analysis. The analysis result of the streams is summarized based on the linear, areal, and relief aspects. The area is characterized by a dendritic drainage pattern which is characteristics of massive hard rock terrain. The Aynalem and Illala streams are 4th and 5th order streams. Considering the number of streams in the Aynalem (75.81%) and Illala (74.66%) is composed of first-order streams that indicate a flashy flood and the mean bifurcation value of Aynalem (6.8) and Illala (4.7) shows that the Aynalem area is more structurally affected than Illala but both show less stream integration. The analysis of areal aspects such as elongation ratio, circularity ratio, and form factor has indicated that both streams are characterized as elongated streams, this implies that both streams are flowing in heterogeneous rock material, presences of structural effect, and slow runoff discharge. The other areal aspect such as drainage density, stream frequency, infiltration number, and length of overland flow all show smaller values in both streams. This implies that the streams are characterized by a relatively permeable rock material with a higher infiltration capacity. The relief aspect of the Aynalem and Illala was also analyzed using basin relief, relief ratio, ruggedness number, hypsometric curves, and Hypsometric integral. The streams are characterized by a lower relief ratio and ruggedness number which implies a relatively flat slope and lower relief. The hypsometric curves and the Hypsometric Integral of the streams indicate that the Aynalem and Illala are at the maturity stage. This shows the area is characterized by higher erosion but less affected by recent structures. Based on the morphometric parameter analysis result it is possible to conclude that the stream development is dependent on the topography and geology of the study area and both streams show similar morphometric character.","PeriodicalId":18948,"journal":{"name":"Momona Ethiopian Journal of Science","volume":"1 1","pages":""},"PeriodicalIF":0.3,"publicationDate":"2021-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"70566760","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
T. Ketemaw, Abdelwassie Hussien, Fethangest Woldemariyam Tesema, Berihu Abadi Berhe
Dijil River catchment is a sub-catchment of the Abay drainage basin and covers 138.28 km2. This paper presents numerical groundwater flow modeling at steady-state conditions, in a single-layer aquifer system under different stress or scenarios. A numerical groundwater flow models represent the simplification of complex natural systems, different parameters were assembled into a conceptual model to represent the complex natural system in a simplified form. The conceptual model was input into the numeric model to examine the system response. Based on geologic and hydrogeological information, confined subsurface flow condition was considered and simulated using MODFLOW 2000. The model calibration accounts matching of 24 observation points with the simulated head with a permissible residual head of ±10m. The sensitivity of the major parameters of the model was identified during the calibration process. According to the simulated water budget in the model, the simulated inflow is found to be 1.2791870E+05 m3/day which is nearly equal to the simulated outflow of 1.2791755E+05 m3/day with the difference being only 1.1484375E+00 m3/day. Water budget analysis reveals that outflow from river leakage accounts for 92.8 % of the total outflow and 14.1 % of the total inflow comes from the river leakage in the study area. Three scenarios of increased withdrawals and one scenario of altered recharge were used to study the system response. Accordingly, an increase in well withdrawal in scenario-I (existing wells pump simultaneously), scenario-II (existing drilled wells yield withdrawal increased by 30%), and scenario-III (additional eight wells having expected yield of 30 l/s drill and pump) resulted in an average decline of the steady-state water level by 1.06m, 1.68m, and 4.46m, respectively. They also caused the steady-state stream leakage to be reduced by about 2.93%, 4.58%, and 11.23%, and subsurface outflow by 9.41%, 14.67%, and 37.86%, respectively. A decrease in recharge by 25% and 50% results in a decrease of the head by 6.1m and 13.4m respectively, and a stream leakage decrease by 20.3%, and 40.3% respectively as compared to the simulated steady-state value. Therefore, adequate groundwater level monitoring wells should be placed in the catchment to control the total abstraction rates from the aquifer and fluctuations in groundwater levels.
{"title":"Numerical Groundwater Flow Modeling of Dijil River Catchment, Debre Markos Area, Ethiopia","authors":"T. Ketemaw, Abdelwassie Hussien, Fethangest Woldemariyam Tesema, Berihu Abadi Berhe","doi":"10.4314/mejs.v13i1.5","DOIUrl":"https://doi.org/10.4314/mejs.v13i1.5","url":null,"abstract":"Dijil River catchment is a sub-catchment of the Abay drainage basin and covers 138.28 km2. This paper presents numerical groundwater flow modeling at steady-state conditions, in a single-layer aquifer system under different stress or scenarios. A numerical groundwater flow models represent the simplification of complex natural systems, different parameters were assembled into a conceptual model to represent the complex natural system in a simplified form. The conceptual model was input into the numeric model to examine the system response. Based on geologic and hydrogeological information, confined subsurface flow condition was considered and simulated using MODFLOW 2000. The model calibration accounts matching of 24 observation points with the simulated head with a permissible residual head of ±10m. The sensitivity of the major parameters of the model was identified during the calibration process. According to the simulated water budget in the model, the simulated inflow is found to be 1.2791870E+05 m3/day which is nearly equal to the simulated outflow of 1.2791755E+05 m3/day with the difference being only 1.1484375E+00 m3/day. Water budget analysis reveals that outflow from river leakage accounts for 92.8 % of the total outflow and 14.1 % of the total inflow comes from the river leakage in the study area. Three scenarios of increased withdrawals and one scenario of altered recharge were used to study the system response. Accordingly, an increase in well withdrawal in scenario-I (existing wells pump simultaneously), scenario-II (existing drilled wells yield withdrawal increased by 30%), and scenario-III (additional eight wells having expected yield of 30 l/s drill and pump) resulted in an average decline of the steady-state water level by 1.06m, 1.68m, and 4.46m, respectively. They also caused the steady-state stream leakage to be reduced by about 2.93%, 4.58%, and 11.23%, and subsurface outflow by 9.41%, 14.67%, and 37.86%, respectively. A decrease in recharge by 25% and 50% results in a decrease of the head by 6.1m and 13.4m respectively, and a stream leakage decrease by 20.3%, and 40.3% respectively as compared to the simulated steady-state value. Therefore, adequate groundwater level monitoring wells should be placed in the catchment to control the total abstraction rates from the aquifer and fluctuations in groundwater levels.","PeriodicalId":18948,"journal":{"name":"Momona Ethiopian Journal of Science","volume":"1 1","pages":""},"PeriodicalIF":0.3,"publicationDate":"2021-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"70566825","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
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