School of Civil and Environmental Engineering

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2D Hydrodynamic Modeling of Rib River Flooding
(Addis Ababa, 2011-10) Shiferaw, Muluken; Michael, Yonas (PhD)
Flood occurs repeatedly in Ethiopia and cause tremendous losses in terms of property and life, particularly in the lowland areas. The majority of flood disasters’ victims are poor people living in nearby stretch of floodplain. Therefore, the study was carried out to perform floodplain analysis and risk assessment of Fogera and nearby areas. This research involves the integration of 2D Structured Mesh Generator (CCHE-MESH) and hydrodynamic numerical model (CCHE2D model) with Geographic Information Systems (GIS) to develop a regional model for floodplain determination and representation. The study describes the flood extent and depth in the area for flow condition derived from the historical flow data of the Rib River. Triangulated Irregular Network (TIN) was prepared from shape file generated from spot elevations of the floodplain through field survey data and the DEM of the study area in ArcGIS. Triangulated Irregular Network (TIN) is converted to an ASC II format, which is supported by the CCHE-MESH and CCHE2D model. Boundary condition for the inlet is specified as total discharge and discharge hydrograph for steady and unsteady simulation respectively and for the outlet a constant water level of Lake Tana (1788m) is specified as a downstream BC which allows for simulation of the free flow condition at the river outlet. Initial conditions are defined based on information on gauges or through introducing a so called warm-up that precedes the actual simulation period and boundary conditions are generally specified from hydrometric data such as time series data of discharge and stage or simulated discharge hydrograph. Maps of flood Extent, Level, Depth and Velocity are developed using 100 years return period flood. The Flood has the inundation area of 47.13km2 while the simulated flood extent has flood depths less than 5.9m. The depth between 5.9m and 2m is located along the river channel and on the pond which is located south of the rib river. However, the depths below 2m exist largely on the flood plain which extend 4 km and 3 km outside right bank and the left bank of the main river respectively. The simulated water level ranges between 1798.4m ASL at the upstream and 1788m ASL at the downstream end of the main river. The simulation result indicates much of the flooding occur in the middle part of the river where the flow behaviour is mainly dominated by the inflow from the Rib River. Most of the areas around the flood plain are cultivated land with less proportion of Agro-pastoral, Marsh and Pastoral. 85-90% of the flood inundated areas are covered by agricultural land. The remaining 10-15% is covered by Agro-pastoral near inlet to Lake Tana.
3D Gravity Inversion for Mineral Exploration Over Southern Green-stone-Belts of Ethiopia
(Addis Ababa University, 2022-03) Girum, Ashenafi; Tulu, Besha (PhD)
Mainly this study aimed to investigate subsurface geology of the southern green stone mineralization zone for evaluation of gravity inversion is how effectively detecting high-density mineralization. Throughout the project, three main tasks have done: the first task was carrying out necessary correction for observed gravity data. Under this stage three main outputs were obtained: Bouguer gravity anomaly, regional Bouguer anomaly and residual Bouguer anomaly. The target information is represented by residual anomaly therefore it is became the final data for inversion process. The second task was minimizing Tikhonov’s cost function and carrying out inversion with the help of a conjugate gradient algorithm after formulated sensitivity matrix. The interpretation process was the last step of the work. The results obtained from the inversion process are demonstrated in two forms: the first one was a horizontal slice that illustrated the trend of mineralization in a horizontal plane and the second was density contrast model in a vertical plane that illustrated at four different lines of cross-section. In the horizontal density contrast model, the pixels value of high-density contrast under mineralization zone revealed 76.8% of pixels made a good agreement with the mineralization history of the target region. In addition, 90.3% of high-density contrast agreed with the location of metallic minerals in the region. In contrast, very low-density contrast in the region scored 3.77%. Therefore the inverted density contrast model well demonstrated the signature of mineralization in the target region. The vertical slice of the density contrast model indicated the depth condition of the high anomalous density region. Thus cross-section profile 1 up to 4 maximum depth and percentage of high density contrast above 600m depth are 1309.464m, 1089.866m, 847.72m, 661.0338m and 81.5%, 72%, 86.3%, 99.1% respectively. The vertical patterns of high-density contrast are correlated with the information obtained from a borehole at the mineralization zone. From such results and validation, I concluded: gravity anomaly inversion is a good tool to detect the position, depth extent, and the trend of the significant anomalous region.
5D Planning, Scheduling and Control of Construction Projects by Integrating Project Management Software and GIS
(AAU, 2017-12) Sitota, Girma; Abebe, Dinku (Prof.)
Construction industry can be deemed as the most vital driving force of a country. Construction of vast projects such as township, stadiums, and dams is a challenging task both in terms of managing complexities of the project and addressing the demands of all stakeholders. Its success or failure largely depends on cost effectiveness, time-bound delivery, quality and amount of resources available throughout the lifecycle of the project. This clearly turns the focus towards effective construction project management. Today’s demand of construction industry requires highly accurate planning, scheduling and management of the process of a project which can enable the overall optimization of cost, time, and resources. With the advances in information technology, its use is being constantly explored in the area of construction planning and monitoring. The aim of this study is to demonstrate the methodology of integrating Geographic Information System (GIS) with construction project management to provide a better solution for optimization and real time monitoring of the progress of a project. GIS is a computer based tool and being used extensively to solve various engineering problems involving the use of spatial data. The technology provides capabilities to solve problems involving creation and management of data, integration of information, visualization and cost estimation to which most of the construction management software are lacking. In spite of the growing popularity its complete potential to the construction industry has not been realized. Integration of GIS and Project management might assist a planner in a better perception of a project as well as in the integration of other parties’ activities in the planning process. It will provide a common basis of understanding and communication among stakeholders. This helps in reducing construction errors occurring on sites and thereby reduces the amount of administrative time. In this research paper a review of up-to-date work on the applications of GIS technology in construction industry is presented. Methodology to generate 3D view of a building and to represent construction schedule within GIS environment is also discussed. With this, integration of GIS and Project Management is developed using AutoCAD, MS-Excel, ArcGIS, and Visual Studio to assist construction managers in controlling and monitoring a construction progress. With time as the fourth dimension, the progress of construction task can be displayed as 4D (3D + time) view. The 5D (3D + time + cost) model of progress monitoring is beneficial to all stakeholders and can be opted as the future of planning and monitoring in the fast developing construction industry. A case study of one story building is selected for the purpose of presenting the integrated tool for progress monitoring. Ultimately, an easy to use Graphic User Interface (GUI) named as “5D Construction Monitoring Application” is developed to enable project participants have an idea of the current status of a project at run-time. The paper explores the potential of GIS environment in developing a construction project information system for rate analysis; and safety and quality control recommendation. It also suggests that the proposed GIS based methodology may replace manual methods used to extract information from the available database and can be easily updated as most of the information is in digital format. Successful project control is a challenging responsibility, but the job becomes easier when it is complimented with visualization of information. The propositions presented herein could facilitate and accelerate this trend, and as well provide means of measuring the success of implementation of 5D planning in construction projects and be a basis for further research.
A Comparative Study of Limits on Normalized Axial Loads of Es-En 1998:2015 With Other Current Major Building Codes on Columns
(Addis Ababa University, 2024-04) Abel Negussie; Adil Zekaria (PhD)
Axial loads highly affect the behavior of reinforced concrete members, such as failure mode, yield curvature, ultimate curvature, curvature ductility, beam-column joint, etc. In order to limit the adverse effects of axial loads, Ethiopian Standards based on Euro-Norms limits normalized design axial compressive loads. This research explores the basis for these limits and then compares them with other major codes and standards. The primary aim for these limits is for the axial loads not to exceed loads at balanced failure, . To study the balanced conditions, a series of interaction charts were constructed with the confinement effect of transverse reinforcement on concrete considered. The three main parameters for the charts are the distance of compression reinforcement from the extreme compression fibres normalised with respect to effective depth, ⁄ , mechanical reinforcement ratios, , and mechanical volumetric ratio of confining reinforcement, . Sectional properties, i.e., yield curvature, ultimate curvature and curvature ductility, under the obtained balanced axial loads were compared to their perspective limits. It was concluded that is highly affected by , and to a lesser extent by and . It has an inversely proportional relationship with both , and . Fifteen different column section was also considered as an example, and their results are in alignment with the interaction charts. From the results obtained, it can be concluded that the limits can be more directed for values of . This is especially the case for column sections having lower values of which show a greater load capacity than the set limits.
A gravimetric method to determine horizontal stress field due to flow in the mantle in East Africa Great Rift Valley
(Addis Ababa University, 2023-07) Abenezer Getinet; Andinet Ashagire (Phd)
The gravimetric approach has been widely used to determine the stress field of subsurface geology of the earth crust. Mainly this study aimed to determine lithospheric shear stress in the Earth’s mantle and its temporal changes caused by geodynamical movements. The gravimetric approach is applied, to evaluate the stress at the base of lithosphere and to detect changes in stress using static gravity field model EGM08 and GRACE monthly solutions respectively. In addition to the static gravity field data some physical information about topographic height, crustal thickness, and lithospheric thickness are incorporated in this method. As a result, more geophysical information and data are applied for computation of horizontal lithospheric stress in this approach. To do so, depth of the base of lithosphere determined by subtracting topographic height from lithospheric thickness is needed, thus the lithospheric shear stress component computed at the base of lithosphere. Moreover, the comparison of lithospheric shear stress using different static gravity field models are performed. The estimated horizontal shear stress at the base of the lithosphere throughout the study area revealed 55.68% of the stress is oriented in a northward direction and the remaining 44.32% is oriented in the southward direction; 44.41% of the stress is oriented in an eastward direction and the remaining 55.59% is oriented in the westward direction: and the result of the estimated horizontal shear stress magnitude ranges from ≈ 0.04 MPa to ≈ 15.32 MPa. Furthermore, the estimated horizontal shear stress components show good agreement with the tectonic boundaries and the location of stress regimes in the WSM2016 database, as well as the seismic events in the study area.
Abay Basin Water Allocation Modelling Using Hec Ressim
(Addis Ababa University, 2009-10) Wondye, Fanuel; Seleshi, Yilma (PhD)
Despite Ethiopia possesses abundant water resources potential, second only to Congo in all of Africa, the country is at critical cross roads with large and increasing population, a depressed national economy, insufficient agricultural production and low no of developed energy sources. 83% of Ethiopians lack access to electricity; only 5 percent of irrigable land and 3% of the hydropower potential in the Blue Nile basin has been developed so far. Nowadays persisting drought and increasing competition for water have left Ethiopia with no more chance other than seeking solutions and assure sustainability of the resource. Even though Ethiopian portion of Blue Nile, Abay possesses a great potential of irrigation and hydropower developments, the financial and political constraints have long hindered the country’s development. This study aims at analyzing the effects of implementing the potential irrigation and hydropower projects that are contemplated in the country. Reservoir system simulation (Hec-ResSim) software has been used to study the out puts of executing different developments in the basin. This has been done by setting up the model and simulating for four scenarios including the base scenario referring to the current situation in the basin. After a curious filtering of all projects mentioned in the basin’s master plan and other project specific reports, 315,431ha (38.7% of total 815,581ha potential) of irrigation and 7,026Mw (89.6% of total 7845Mw potential) of hydropower potential; overall comprising 23 dams having a combined maximum storage capacity of 170.15Bm3 have been preferred to be analyzed and assessed using the model. After categorizing these projects under four scenarios; the simulation has been done based on 33 years (1960-1992) of monthly hydrologic flow series. vi This study under has indicated that If Ethiopia is to develop 315,431ha and 7,029Mw, the resulting decline in the cross border flow will be only 3,382.93Mm3 which is only 7.29% of the currently simulated (under current condition scenario,scenario-1) Abay discharge to Sudan which is 46,396.99 Mm3. Under this condition both Ethiopia and Sudan benefit from regulation of Abay by Ethiopian dams, in that it results in increasing of low flows, giving the whole system uniformity of balance, decreasing water escaping during flood seasons. As concluded from this study regulation works upstream in Ethiopia have resulted in a uniform monthly average flow of 3,584.51Mm3 throughout the year to Sudan. Currently as the base case simulation indicated, Sudan receives monthly average low flow of 1,233.54Mm3 through November to June which then turns to be increasing; August being flood month when 13,456.27Mm3 has been observed. In addition if Ethiopia is to develop 7,029Mw including hydropower projects on the tributaries, then some 38,385.81Gwh/annum of electricity will be produced. Even though Tana-Beles project imposes a big deal of inflow and power out put decline on the main stream hydropower plants, this power decrease was exceeded by the power generated at Tana-Beles power plant. Prior to Tana-Beles project Power output from main stream plants has been 34,284.23 Gwh/annum then increased to 34,736.14 Gwh/annum despite power decrease at Karadobi, Mabil, Mandaya and Border.
Accuracy assessment and bias correction for open sources Digital elevation model (DEM): a case study in and around Diredawa city, Ethiopia
(Addis Ababa University, 2022-02) Mesfin, Delelegn; Tulu, Besha (PhD)
Digital elevation model (DEM) is a digital and mathematical representation of the real-world topographic surface by using elevation data. The global open-access DEM data contain errors and are not suitable for engineering and other high accuracy requiring applications. The main aims of this study are vertical accuracy assessment and bias correction for open-source global DEM data. Conventional global DEM data; SRTM DEM 1-arc second and ASTER-GDEM 1-arc second, and new global DEM data ALOS-PALSAR both 12.5 m and 30 m spatial resolution DEM data were applied for this study. Ground control point GCP, RTK-GPS data, and photogrammetric DEM reference data were used to evaluate the accuracy of the selected open-source global DEM data. Accuracy assessment was applied in different approaches, one is a point-based approach using statistical measurement. The computed Root mean square (RMSE) for SRTM is 3.68 m, 4.24m, and 3.41m in GCP, RTK-GPS, and Photogrammetric DEM reference data, for ASTER-GDEM the RMSE value is 8.87 m, 7.08 m, and 7.05 m, for ALOS-PALSAR12.5 m it is 4.58 m, 4.46 m and 4.58 m and for ALOS- PALSAR30 m the value is 5.79 m, 5.10 m and 5.34 m, respectively. The accuracy of SRTM showed better in three reference data and ALOS-PALSAR12.5 m is followed the SRTM in the accuracy. Whereas the accuracy of ASTER-GDEM showed less accuracy among the selected global DEM data. The second approach is based on land use land cover data using RTK-GPS reference data; bare land, road line, drainage pattern, rock area, and tree areas point data are collected using TRIMBLE R8 GNSS/R6/5800 instrument, the accuracy of rock area showed less accuracy in all DEM data except SRTM DEM and the accuracy of the bare land area showed better in all DEM averagely. And the third approach of vertical accuracy assessment is terrain classification; the terrain of this study area is segmented into three classes (flat area, moderate slope, and steep slope), the accuracy of the flat area showed high and the accuracy of the steep slope is less for all DEM data. Finally, bias correction was applied using linear transformation parameters to reduce the residual of the global DEM data, the accuracy of ASTER-GDEM was improved by 22.9 % after the bias correction, while the accuracy of SRTM is improved by 6.7 % and the accuracy of PALSAR12.5m and PALSAR30 m was improved by 5.1 % and 2.2 % after the bias correction.
Accuracy Assessment of Digital Surface Model from Aerial Images: Case Study of Nifas Silk Sub City, Addis Ababa
(Addis Ababa University, 2022-03) Jemal, Endrie; Andenet, Ashagrie (PhD)
Airborne aerial photograph is one of the most effective means of terrain data collection. The vertical accuracy of DSM derived from 2010 and 2016 collected aerial photograph in urban area of Nifas Silk sub city is the critical point in this research. In this study, the reference level produced from GPS elevation, existed GCP elevation and differential leveling are measured to assessed the vertical accuracy of existed GCP elevation and both DSM elevation data derived from Airborne aerial photograph for building urban land cover types. Using static GPS elevation as a reference, the accuracy of existed GCP elevation gave a RMSE value of 1.049m and an arithmetic mean value of 1.049m. GPS reference elevations gave us the RMSE value of 0.592m and 0.787m and an Arithmetic Mean value of 0.466 and 0.659 for used DSM derived from 2010 and 2016 aerial photograph respectively. On the other hand, by using GCP as reference elevation, gave the RMSE value of 0.415m and 0.486m and also used differential leveling elevation, gave the RMSE value of 0.68m and 0.911m for used both DSM derived from2010 and 2016 aerial photograph respectively. A spatial analysis tools can be used for the extraction of DSM elevation in arc GIS software package. Finally, 1.96xRMSE and frequency histogram statistical measurements of data analysis are performed for the difference between measured independent checkpoints and corresponding point of both DSM derived from the two aerial photographs. For our study area, using the three reference elevation point of existing GCP, RTK GPS and Leveling measurements, DSM derived from (2010) aerial photograph elevation data have an accurate by A RMSE value of ±0.071m, ±0.198m and ±0.231m and/or Absolute Mean value of ±0.071m, ±0.198m and ±0.379m that of the value of DSM derived from (2016) aerial photograph data respectively.
Accuracy Assessment of Geospatial Data for Cadastral Application: A Case of Addis Ababa City, Ethiopia
(Addis Ababa University, 2022-07) Melese Wondatir; Getachew, Tesfaye (PhD)
Datum transformation is the transformation of coordinate points from one known coordinate reference system into another. The recent practice of geospatial data collection, management, and analysis in Ethiopia is in geocentric coordinates of a point defined based on a global datum (WGS84). However, Ethiopia uses Adindan as the recognized local datum. The current official transformation parameters in use by Ethiopia are slightly different from the parameters determined by previous research and adopted in widely used geospatial software packages. In addition to this, the rotation and scale changes are ignored in the transformation parameters. The current practice of cadaster in Addis Ababa city is below the accuracy level of all local and global geospatial data standard guidelines. The main purpose of this study is to assess and evaluate the Accuracy Assessment of Geospatial Data for Cadastral Application: A Case of Addis Ababa City, Ethiopia. Statistical analyses have been done for second-order GCP, orthophoto, and cadastral parcel accuracy assessment analysis based on ASPRS 2014 standards. The positional accuracy of second-order ground control points, orthophoto, and cadastral parcels evaluated by checkpoints is determined as 0.47m, 1.326m, and 1.87m respectively at a 95 % confidence level. Finally, the software packages used to convert from global to local reference datum differ from one another, causing major changes in the values of specific points. Coordinates values of Orthophoto and static GCPs were converted from WGS84 to Adindan using (X = 162m, Y = 12m, and Z = -206m); the RMS error of easting and northing values were 0.32 m and 0.69 m respectively. On the other hand, the static GCPs coordinates were converted by using (X = 165 m, Y =11 m, and Z = -206 m) and compared with orthophoto coordinates, the RMS error of easting and northing values were 2.65 m and 0.78 m respectively. And, according to Molodensky-Badekas seven transformation parameters using (169.674 m in X, 14.801m in y, and -204.841 in Z), the RMS error of easting and northing values were 3.055m and 0.697 m respectively. Finally, the researcher recommends these parameters shall utilize as unique and constant values to improve data integrity for geospatial work such as cadastral application.
Activity-Based Travel Demand Modeling for Addis Ababa
(Addis Ababa University, 2017-11) Mahlet, Demere; Bikila, Teklu (PhD)
Transportation planning has been shifting from an emphasis on capacity expansion to issues like travel management, social equity and environmental justice, quality of life, energy sustainability, and environmental concerns. The trip-based models are not adequate for reflecting these subjects even if they have served the planning needs of metropolitan areas for many years. The activity-based models, on the other hand, are capable of providing estimates of travel demand under a wide range of scenarios at a disaggregate level. Addis Ababa is currently experiencing high urbanization rates. If this issue is not addressed properly, traffic delays and congestion caused by urbanization will have huge impacts on the environment due to noise and air pollutions. Studying the travel behavior of the residents of Addis Ababa is vital in trying to address the adverse effects of urbanization. In this research, the travel behavior and travel pattern of Bole Sub-City residents were studied. For the purpose of building up an activity-based travel demand model, a discrete choice model was used. Activity diaries were distributed throughout the study area and the respondents were required to fill in their activiites for a period of two days. The results of the survey were then analyzed so as to build up the travel demand model. Daily activity pattern, time-of-day choice, and mode choice models were developed. These three models were linked with each other using a sequential Nested Logit framework. The result from the analysis showed that the daily activity pattern of work tours was accurately predicted by the model, with a goodness of fit of 0.883, as opposed to non-work tours which had a goodness of fit of 0.436. The relatively low goodness of fit value for non-work trips was attributed to the fact that over half of the surveyed population performed work activities leaving the rest of the percentage share to be distributed among school, maintenance, discretionary, and other types of tours. This research can be used as a stepping stone for planners and engineers to further develop travel demand models for other sub-cities found in Addis Ababa.
Actual Evapotranspiration Estimation Using Remotely Sensed Data and Hydrological Model: A Case Study Of Gilgelabay Catchment
(Addis Ababa University, 2015) Genet, Abdi; Dereje, Hailu (PhD)
In order to get reliable qualitative and quantitative information about a potential of water resource in a catchment it is important to assess and evaluate the spatial and temporal variation of actual evapotranspiration by applying SEBS algorithm and SWAT hydrological model and eventually compare with MODIS ET. This is one of the motivations for evaluating the spatial and seasonal dynamics of actual ET for the Gilgel Abay catchment using energy balance algorithm and hydrological model. Spatially distributed actual evapotranspiration (ETa) values were estimated using Surface Energy Balance System (SEBS) approach and the Soil and Water Assessment Tool (SWAT). The input data for SEBS and SWAT were acquired from different sources with different spatial and temporal resolutions. The dynamics of ETa was assessed only for the selected dry years (2009) and wet year (2005 and 2007). Moreover, the analysis was based on the nine selected days of those years having a cloud cover less than 30%. The estimated ETa values were also compared with MOD16 ET at sub-catchment scale. SEBS based estimated daily actual ET eventually were compared with MODIS ET and SWAT actual ET estimates to assess the temporal and spatial variability in the catchment. The result showed that the mean value of SEBS daily actual ET during those days reached up to 5.9 mm/d (Jan-01-2005), 5.5mm/d (January 10, 2007) and 5.1 mm/d (March 12, 2007). In distinction as it observed from the results during wet season days the SEBS estimated actual ET is relatively lower and highly variable spatially. The mean actual ET for day of the year [DOY] 253- 2009 is 8.8 mm/d, DOY 336 - 2007 is 5.8 mm/d and DOY 330- 2009 5.1 mm/d which shows the spatial variability resulted due to heterogeneity of the vegetation cover during the wet season. Similarly, the long-term mean annual actual ET derived from previous hydrological studies using SWAT compared well with MODIS ET over the terrestrial part of the catchment. The evaluation of the wet season actual ET from 2000-2010 from MODIS and SEBS was compared with SWAT and the result showed that a good correlation. Thus, overall MODIS ET product showed good agreement with results from the SWAT models both in magnitude and spatial variability
Adama Flood Problem –Flood Risk Mitigation Option for Boku Shenen Area
(Addis Ababa University, 2016-04) Aychiluhim, Merid; Nigussie, Agizew(PhD)
Flooding is becoming a usual event that occurs in urban and rural areas. It is an interaction between mankind and nature. A city like Adama is nowadays becoming a flood prone area. A flood that comes from the adjacent watershed area seriously affects the low lying areas as seen at Adama – Boku shenen Kebele. Boku Shenen kebele is one of a flood prone area of Adama city every year. Four different watershed catchments that produce flood exist around the kebele. Because of lack of integrated flood risk management system; loss of lives, displacement of people, and destruction of social infrastructures are becoming increasing from time to time. Adama has been vulnerable to flash flooding from rainfall, in particular of the ungagged Kersa and Golba Tegene catchments which pass through South East of the city. It has not been tried to estimate the amount of flood and not recommended mitigation options based on the natural situation of the area previously. Hence, this thesis is to identify peak flood and recommend mitigation options based on the environmental and geological situation of the area that can be affected by extraordinary floods. This thesis tries to consider more options and fills the gaps not covered by others adopting more than four application soft wares like Easy fit, ArcGIS, Global Mapper and AutoCAD. Specially, peak flood discharge estimation and recommend mitigation measures selection method believed to be the gap not properly covered in the previous flood risk mitigation works. The data usage for this thesis tried to make very intensive by considering different data options like gridded (DEM and contour), digitized (soil type, land use and 1:50,000 scale map) and rainfall data. For precipitation modelling, ERA Intensity-frequency-duration curve was used for frequency storm and for the gage weights annual maximum daily rainfall for 24 hours and 6 hours duration storm are used since flood estimation requires a properly recorded data more than 30years from metrological stations. For the study area, I just used a rain fall data of 62years of record from Adama meteorological station. 30m x 30m resolution DEM for catchment was used to delineate the watershed area using GIS. In this thesis, the flood magnitude estimated for a 100years return period was computed by using SCS excel model method for Kersa and Golba tegene catchments and flood mitigation option selected to be detention pond incorporating the designing criteria. Adama Flood Problem-Flood Risk Mitigation Option for Boku Shenen Area 2016 Detention pond/dam was designed for both catchments. For Golba Tegene catchment, after analyzing the area of the reservoir/pond, having 8m of dam height 130962 m3 volume of flood can be absorbed/held which a 25 years design flood is. The spillway was designed for 100years return flood and can spill maximum of 5.586m3/s routed discharge. For Kersa catchment, a controlled local pond type of 3m height at 8584m2 and hence 26421m3 volume flood could be held which is also a 25years design flood. It also has spillway and controlled outlet gate that can discharge a maximum of 0.78m3/s. After the junction point of the two gullies a maximum of 6.36m3/s discharge could pass through the existing gully. However the existing gully was modified so as to accommodate safely the maximum 6.36m3/s discharge. In doing so, this thesis will help and become an input in flood risk mitigation process. It will benefit the study area community directly where as any others can be benefited indirectly.
Addis Ababa Road Traffic Accident Study and Possible Engineering Solutions: Case Study of Akaki-Kaliti Sub City Roads
(Addis Ababa University, 2014-05) Gebremeskel, Atsbeha; Teklu, Bikila (PhD)
This study aimed at examining the road traffic accident and possible engineering solutions: with particular focus on Akaki-Kaliti Sub-City roads. To meet the objective of the research the researcher has given attention to collect accident data, road data, and traffic data from Addis Ababa Police Commission, Akaki-Kaliti Sub-City Traffic Office, ERA (Ethiopian Roads Authority), from Addis Ababa Road and Transport Office, and field observations. Calculation and model selection of Black spot identification go with the land characteristics, objective needs, and basing other real factors required consideration the area of the study. Hence, the results of the study showed the existence of large difference in road traffic accident victims among drivers, passengers, and pedestrian in their sex and age levels. The Male drivers, passengers, and pedestrians were the most affected one as compared to their female counterparts. Moreover, the result confirmed that road traffic accident (death, serious injuries and light injuries) in the city mostly affected age categories of between 18-30 regardless of their sex, and starts declining after age 31. Consequently, the road traffic accidents were extremely affecting the economically active citizens i.e., youths and young adult groups. The road traffic accident trends in the Akaki Kaliti Sub-City roads by day of a week revealed significant growth of the severity of the accidents from 2010/11 to 2012/13 in all days of the week except in Sunday. Though it varies in hours of a day, and hence the crash has reached its maximum points when pedestrians, passengers and drivers' frequency of movement has increased, especially after 6:00 AM and reached the maximum accidents at 10:00 AM. Most of these crushes happened in Central Business District (CBD) and market land use areas with collisions like sideswipe, rear end, collision with pedestrians,broad side, and head on collusion. Most of these accidents occurred on Road junction like midblock than the Y– junction and T – junctions. Besides, the highest accident rates were associated with double carriageway in straight and level road character. Depending on these road traffic accidents and the model used areas like Saris Abo roundabout, Tirunesh Beijing Hospital (Near the Bridge), Customs Office Entrance, Total (Kaliti Shoa Bakery), Korki (Medroc) Entrance, Cheralia Biscuit Factory, and Akaki Kela (Near UNISA) were identified as Black spot areas, since they experienced the highest accident rates. Hence, recommendations of Engineering, Enforcement, Encouragement, and Education like, adequate provision of Road safety education, offering of definite land use policy, Quality drivers' training, and testing, standardized and prerequisite criteria for drives with regard to their educational background and good behavior ,traffic signals , traffic lights and their frequent technical failure should be solved, raised zebra crossing, marking zebra crossing, prohibit overtaking, constructing side walkway, widening of the pavement, streetlights, installation of marking and signs, and some areas also consider adequate median road marking, redesign and providing additional-way movement have been forwarded to alleviate the problems.
Adopting Landscape Infrastructure to Integrated urban Stormwater and Wastewater Management
(AAU, 2017-06) Feyisa, Nibo; Agizew, Nigussie (PhD)
The main goal of this study is to evaluate the existing urban wastewater and storm drainage management system and made recommendation on best selected alternative option of integrated urban wastewater and storm drainage management system. Any technical wastewater and stormwater management system adopted in urban drainage based on prior quantitate design discharge estimation. This study contributes a lot to understanding of the integrated urban water management system key technique to minimize the diffuse pollution load into natural stream, to reduce point source/wastewater discharges and to preserve the hydrologic regime of natural drainage systems. Wastewater and stormwater flow discharge are analyzed based on the three-part methodology. The rainfall of 100, 50, 25, 10, 5 and 2 year annual exceedance probability meteorological method was simulated SCS unit hydrograph rainfall-runoff using HEC-HMS. The calibration result indicates basin parameters were used in HEC-HMS model is improved. Different scenarios for landcover change were evaluated for all rainfall frequency models. The frequency storm of 25 year return period produced the maximum peak discharge at the outlet found 209m 3 /s in 1995, 238.1m 3 /s, in 2002 and 262.6m 3 /s in 2009. The hydrological response indicated that with urban area increase by 24.95%, an increase in peak flow. This study shows that peak discharge increase in 13.87% in period 2002, 25.64% in 2009 compared to period of 1995 as reference. The storm drainage management infrastructures are not updated – not sufficient to the peak discharge. Flooding impact on streets, and public property damage were reported in every year. The wastewater generation from domestic, industrial, public and intuitional have direct relation water supplied and 80% of water used is changed to wastewater. Monthly billed volume of consumed water from 2011 to 2016 was evaluated to determine domestic per capita demand. The average per capita demand is found 26.74l/cap/day. Per capita demand by mode of service were found 89.2L/cap/day for High Consumption, 41.48 L/cap/day medium consumption , 21.06 L/cap/day low consumption, and 9.88 L/cap/day very low consumption. From these demand estimation the total wastewater flow rate are found 2898.9m 3 /day (0.0334m 3 /s). Only 255m 3 /day (4%) of sewer facilities is existed for wastewater management system. These infrastructures are limited to only to onsite sewer line connected to the flash toilet, off-site pitlitrine discharged to treatment plant. GIS specific landscape Suitability assessed where specific practice to place, i.e. integrated urban water management system like stormwater best management practice and Wastewater Generation Reduction. The evaluated stormwater best management practices selected is Sediment Basins, Sand Filters Pervious landscape Pavements, Bio Basins, Infiltration, Ponds and Lakes, Swales & Buffer Strips, Bio Swales, Constructed Wetlands. For wastewater reduction the selected are Stormwater Harvesting/Reuse, Rainwater Tanks, Changing Landscape Form and Water Use Education Programs.
Advancing Bioassessment of Water Quality in Wadeable Rivers and Streams in Ethiopia
(Addis Ababa University, 2024-01) Melaku Getachew; Seid Tiku (Prof.); Geremew Sahilu (PhD); Worku Legesse (PhD); Mary Kelly-Quinn (Prof.)
Numerous international bilateral, plurilateral, and multilateral treaties and conventions were signed between countries to protect human health and environmental pollution. However, most of the signatory countries fail to implement the treaties or conventions (Willis, 2012). For example, though Ethiopia has endorsed or ratified the Basel, Stockholm, and Rotterdam agreements, its legislations and policies for environmentally sound management of hazardous chemicals and wastes are still in infancy and are inefficient in preventing the illegal dumping of waste as well as contamination of water, soil and air resources (Tadesse, 2009). This study reviewed the details of problems of surface water pollution in the metropolitan area of Addis Ababa and the upper Awash River catchment. Urbanisation, population growth, industrialisation without proper waste management facilities, unregulated agricultural practices, uncontrolled liquid and solid wastes, and law enforcement difficulties were the major gaps identified. Furthermore, there are significant gaps limiting efforts to address the magnitude of pesticide pollution in the catchment probably due to the shortage of laboratory facilities and the costs associated with the chemicals and equipment. This study forwarded important conclusions and recommendations to the respective stakeholders. To help the bioassessment of wadeable rivers and streams in Ethiopia, a macroinvertebrate kick sampling protocol has been developed using data from minimally impacted sites and testing it along the pollution gradients. Based on the results, the 2-minute RH kick sampling method is the recommended candidate for the bioassessment of wadeable rivers and streams in the country. Using the developed macroinvertebrate kick sampling protocol in this study, the impacts of the Koka Hydropower dam on benthic macroinvertebrate structure and composition were further investigated. Hydropower has been used for generations to provide reliable, fossil-fuel-free electricity (source of clean energy), water supply for domestic uses and agricultural irrigation, recreational opportunities, several flood-control benefits, as well as a stable system for navigation. However, several disadvantages have also been recognised because of the construction of hydropower dams. It is particularly severe in large dams where there has been extinction of the many fish and other aquatic species, huge losses of forest, the disappearance of birds in floodplains, erosion of deltas, loss of wetland and farmland, and many other irreversible impacts. These impacts can have economic and social (e.g. Community displacement) health implications (consequences). This in turn points towards the need to seek a balance between pros and cons associated with dam construction. Currently, most public and policymakers perceive only the advantages (pros) of the hydropower dam and the impacts mentioned above are largely neglected. To create awareness among stakeholders and to recommend possible solutions to the problem, it was very crucial to conduct the ecological impacts of hydropower dams on the macroinvertebrate communities that include aquatic insects, crustaceans, annelids, mollusks, nematodes, planarians, and other invertebrates as these organisms play a critical role in the transfer of energy from basal resources (bottom layer) (e.g., algae, detritus, and associated microbes) to vertebrate consumers in aquatic food webs, and they serve as the primary food resource for many commercially and economically important fish species. The investigation of the hydropower dam on the structure and composition of macroinvertebrate communities showed that the downstream reach was severely impacted by water pollution compared to the midstream and upstream reaches of the Awash River, however, the results were partly complicated by the nutrient pollution, particularly from the midstream reach. The major factor, amongst others affecting the downstream reach, the water flow change (river velocity) was highlighted as a key variable structuring the macroinvertebrate communities and a variable that can be altered by damming. Similarly, variation partitioning analysis was used to analyze the unique and shared effects of the three sets of predictor variables (environmental, land use, and spatial factors). The findings revealed that the three sets of predictors' shared variation in macroinvertebrate community composition was greater than their contributions. To put it bluntly, anthropogenic activities have a negative global influence on aquatic habitats. As a result, surface water biomonitoring is becoming increasingly crucial in estimating ecosystem deterioration and achieving environmental sustainability. Therefore, the development of methods kick sampling time) based on Ethiopian ecoregions to employ in the bioassessment of surface water quality has been mandatory. This would contribute to the assessment of water quality in wadeable rivers and streams in Ethiopia
Agricultural Land Suitability Analysis Using GIS and Remote Sensing Techniques: The Case of Mecha Woreda, Amhara, Ethiopia
(Addis Ababa University, 2024-01) Abebe Negussie; Hamere Yohannes (PhD)
Agricultural land suitability study plays a vital role in determining forthcoming agricultural cropping patterns, as well as in the formulation of plans and activities related to agriculture. The assessment of land suitability is a critical endeavor that involves the evaluation of a specific area to ascertain its appropriateness and suitability for a particular use within a given locale. This process encompasses a comprehensive analysis that takes into consideration a multitude of factors, including soil characteristics, climate conditions, topographical features, and the availability of water resources. This analysis on land suitability employs a multi-criteria analytical approach in order to determine the most appropriate land for rain-fed purposes. The results of this analysis demonstrate that a considerable proportion of the region being examined exhibits a high level of suitability for agricultural activities. Approximately 20.92% of the region can be designated as significantly suitable for agricultural practices, and an additional 33.03% can be described as highly suitable. These statistics reveal that around 54% of the entire area possesses a substantial capacity for prosperous farming endeavors. According to the research's discoveries, a substantial segment of the evaluated territory is either highly suitable or very high suitable for irrigation, with a combined total of 82.66%.However, there are also notable areas that are only moderately or low suitable (13.96% combined), while a smaller proportion is not suitable (3.38%) for irrigation purposes In conclusion, the results suggest that a significant proportion of the region being examined exhibits a considerable level of suitability, ranging from high to extremely high, for agricultural purposes.
Agricultural Water Management Modeling and Analysis Under Climate Change and Land Transformation (A Case Study of Lower Omo Ghibe Basin)
(Addis Ababa University, 2018-05) Natan, Molla; Daniel, Fikreselassie (PhD)
Human activities and climate factors both affect the availability of water resources and the sustainability of water management and that in turn affect agricultural water management especially in already dry regions, water has become scarcer with increasing requirements from growing population, economic development. Although progress has been made in understanding variability of runoff, the impacts of climate variability and human activities on agricultural water management (actual evapotranspiration) and (discharge accumulated in the river network) remain less well understood. South omo Gibe basin which is one of the sub basin in Ethiopia has suitable land water resource for agriculture for both farm and livestock and currently huge investment are found on irrigation project, and from these the dominant is state owned irrigation like kuraz sugar development irrigation project in the sub basin which planned to irrigate sugarcane on 175,000 hectare of land. According to works design and supervision enterprise that prepare design document of the project the water requirement of the plant is modeled with cropwat considering only atmospheric water demand and put the yield in figure in its report. However now a time In south Omo Gibe sun basin a frequent happening of high and low rainfall, less work on soil conservation practice and deforestation are observed as causes of changing of climate and land degradation that make the need for improved and resilient agricultural water management to have greater yield of the crop with environmental sustainability and so efforts towards improved and resilient agricultural water management is must. Therefore, the main objective of the research presented here is to study the effect of climate change specifically drought and land degradation on water demand and crop yield in the area of study and compare the existing crop oriented model used for the design of crop water requirement of the crop in the project area with agro hydrological model for better irrigation management under climate change and land transformation. To achieve this purpose, an available code that takes into account the interaction between soil, water, atmosphere and plants SWAP model is used after assessing the challenges in the sub basin and identifying adaptation strategy for improved agricultural water management and compared with Cropwat model. consequently, it is tried to analyze the impact of future climate changes and land transformation water demand for irrigation and relative crop yield in the Kuraz irrigation project area. From the result of the performance of the two model SWAP model result of actual evapotranspiration and irrigation water requirement is greater than the designed crop water requirement of cropwat model output which can be calibrated with yield of sugarcane. And the comparison of the two models shows that SWAP model outputindicate the actual evapotranpiration and irrigation water requirement is greater than the CROPWAT model output f the designed irrigation water requirement that can make conform with yield reduction of sugarcane the in project area as a calibration method due to shortage of data. Even though the reduction of sugarcane is happen due to technical inefficiency as I can get the result of research paper on irrigation management practices in kuraz irrigation project, climate change and land degradation plays large effect in this technical inefficiency of irrigation water management more than different tillage practices. in this research due to shortage of data to measure soil moisture and ground water data in the project area I used the yield reduction data from analysis of technical efficiency sugarcane production. From this result neglecting other factors that decrease the yield of sugarcane and considering the effect of climate change and land degradation only, it shows the need of irrigation water will be high to maintain good yield of sugarcane in the future. Today, the sugar corporation supplies 300 m 3 /sec which is the minimum release discharge from Gibe III hydropower project. This means that the corporation should focus on works that increase the amount of water for irrigation in the future. Consequently, taking into account all the simplification and the uncertainties in the model, it is safer for the corporation to increase the water supply capability in the future, particularly using a better approach of soil and water management integrated with sub basin scale soil and water conservation practices should be followed, in order to cope the increasing water demand in the future.
Alternate Solution to Lake Beseka Water Level Rise Containment
(Addis Ababa University, 2017-06) Lulit, Habte; Mebruk, Mohammed (PhD)
Environmental change that has taken place over the last few decades is an essential task to understand the impacts that natural processes and anthropogenic factors have on hydrological settings and ecosystems. Environmental concern regarding the expansion of Lake Beseka has become a major issue. The expansion of Lake Beseka has caused an irreversible damage to the nearby Awash River which is a resource for the surrounding irrigation schemes and downstream water supply. This paper tried to predict the maximum possible Lake level so that it is contained in its territory to control the contamination of Awash River. A numerical groundwater model, TAGSAC, has been used for predicting this maximum possible Lake level rise. For the identification, a steady state groundwater model was first created and calibrated for the inventoried wells. The model is conceptualized by considering a constant head boundary condition for the Awash River in locations where the river is perennial. The calibration of the model was made by changing the recharge and hydrogeologic parameters of the basins. The goodness of fit indicators (GoFIs) showed that the measured and simulated heads of the model have a better match. The maximum Lake level rise was determined by raising the lake water level where the flow was reversed away from the Lake by assuming the Lake is contained in its territory. As the result of this study indicates the maximum Lake level where the flow completely reversed is 12m.
Alternative Approach for The Analysis of Suspended Slab Panels Under Partition Wall Load
(Addis Ababa University, 2005-06) Seyoum, Thomas; Zekeria, Adil(PhD)
Analysis techniques for most structural elements with different arrangement of externally applied loads are well developed and sufficiently covered with modern analysis theories. Further more, the application of today’s high-speed computers enables the analysis of complex structures with different load arrangements. In addition to these effective analysis tools, building design codes provide table of values and analysis charts for the analysis of different elements of structural systems. As one of the structural element in building structure, different analysis methods were proposed for the analysis of suspended slab panel subjected to non-uniform loads. Among the possible arrangement of externally applied loads on suspended slab panel a line load is the one which can best represent the weight of partition wall on it. Different simplified analysis methods were proposed to consider the contribution of this load to the design action effects. The current practice of accounting this partition wall loads in the analysis of suspended slab panel is to change it to the 'equivalent' uniformly distributed load. The analysis of regular slab panel subjected to uniformly distributed load may be carried out using computer softwares or using coefficients which are presented in many design codes (including the Ethiopian Building Code of Standards for concrete structures, EBCS 2 – 1995). The Swedish method and Reynolds method can be referred as some of the examples which are used to obtain equivalent uniformly distributed load. These methods analysis need to be investigated whether they can represent the actual load or not. Therefore, as it is important to address this problem, comparative analysis has been carried out. A new simplified method which considers the actual scenario has been developed. This newly proposed method makes use of coefficients derived from the basic principle of elastic analysis of plate. The results have been verified by comparing it with results of the finite element analysis. It enables us to make elastic analysis of suspended slab panel subjected to the weight of partition wall and avoids the uncertain use of approximate methods.
Alternative Concrete-Steel Building Construction for Social Housing Projects
(Addis Ababa University, 2008-11) Eshelll, Tsehaye; Taye, Shifferaw(PhD)
In this thesis an alternative steel-concrete social-housing is studied with the comparison of the existing cost-efficient construction projects. To accomplish the work the presenter has been point out the problems manifested in the country especially the capital city, Addis Ababa besides the historical development, role and policies of social-housing is presented. In addition the design of G+4, Type B social-housing building is considered in the course of this the design guide line from the design of roof to the footing design is carried out. To complete the design the 3D Model of the frame is analyzed using ETABS 9 software; all loads induced on the frame are considered. Besides the design of the building some construction defects of the normal concrete construction is stated. Since the main aim of this thesis is focused on the alternative steel-concrete social-housing building, the design guide line is specified. The steel process from the design to erection is accomplished by considering bill of materials, erection and detail drawing. And special consideration in structural design and construction is prepared. Finally, the comparison and structural evaluation of the two systems is carried out based on economy, and management and efficiency. From the comparison, some conclusion and recommendation are forwarded.

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