Browsing by Author "Zelalem Tesfaye"

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    Grand Ethiopian Renaissance Dam Reservoir Operation Simulation using HEC-ResSim and its impact on downstream Hydropower Generation
    (Addis Ababa University, 2014-03) Zelalem Tesfaye; Yilma Sileshi (PhD)
    In this study, HEC-ResSim model was used to simulate operation of existing hydraulic infrastructure, and major irrigation schemes in the Eastern Nile river basin and the new hydraulic infrastructure (GERDP).The main objective of this research is to find out the extents of the impact to which the introduction of new upstream reservoir, GERDP, on downstream users of the Nile waters by using the HEC-ResSim reservoir simulation model. Repeated runs of the HEC-ResSim model were made using different filling and after filling of GERDP scenarios to compare the effect of GERDP under alternative operating policies. The computational algorithm in HEC-ResSim is divided in to three major components: (1) watershed setup, (2) reservoir network, and (3) simulation for Calibration, Baseline and Alternative (Dry, Wet and Average filling and after filling) phase scenarios. The methodology computes the required releases to limit storage to the capacity available based on the probabilistic properties of future flows, conditional to current stream flow conditions. The first setup was to simulate gaged flow routing without taking into account effects of development using the flow data of 1956 to 2003 and a good agreement was observed between simulated and gaged data at El-Deim, Khartoum, Dongola, Hassanab and Tamaniat stations. The correlation coefficient R2 values for those stations were found to be in good agreement and found to be more than 0.925 for each station. Following this, the model was configured to simulate the existing and proposed development intervention. The baseline development Scenario is considering only existing major water infrastructures (i.e. reservoirs) and major irrigation schemes in Sudan and Egypt for a period of 1956 to 2003. The simulation result showed that an average annual energy of 14,810.83GWh/year is produced by Roseires, Sennar, Merowe and HAD. The Alternative scenario development which includes during filling and after filling of GERDP, HEC-ResSim simulation, has discovered that long term effects of new upstream reservoir on the operation of downstream reservoirs. After filling of GERDP phase scenario simulation using flow data of 1956 to 2003, the simulation result showed that an average annual energy of 31,363.63GWh/year will be produced by GERD, Roseries, Sennar, Merowe, and HAD (111.76% increase than without GERD), the reduction of average annual energy by 395.41 GWh/year from HAD will be compensated by the energy produced by GERDP and Sudan power plants, which will increase the total energy produced by the whole Eastern Nile system. During the filling phase scenario simulation results showed that an average annual energy of 27,041.96 GWh/year, 25,695.48 GWh/year, and 31,213.61 GWh/year will be produced by the 5 power plants during Average, Dry and Wet filling Scenarios respectively and average annual energy production from GERDP will be 11,314.38, 8,974.19, and 11,925.61GWh/year for the respective sequence of filling years. An average monthly power of 1,625.46MW and average annual energy of 14,238.99GWh/year will be produced during normal operation of GERDP (i.e. after filling from 2019-2066 for 48 years). Due to upstream regulation (i.e. intervention of GERDP, in the upstream of the Eastern Nile river basin) there will be an increase in average monthly inflow downstream in the driest month of the year and the annual average reservoir pool level increase which result in increase of power head.
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    Media Communication Campaign in Promoting Free Public Discussion, Dialogue and Debate on HIV/Aids and Sexuality Related Issues: The Case of Amhara Radio
    (Addis Ababa University, 2010-06) Zelalem Tesfaye ; Negussie Teferra
    This study was conducted to examine the role of the 'Se'ate HIV' live radio phone-in program of the Amhara Mass Media Agency in promoting free and open public discussion, dialogue and debate regarding human sexuality, especially of risky human sexual behaviors , and other sexuality related issues which have long been conceived as culturally taboo by the society at large . To achieve the goal of this study, qualitative research design was found to be the best research methodological framework to gather data which are thought to be relevant to the study. To this end, the study employed focus group discussions and individual in-depth interviews as tools to generate data from sexually active age brackets ranging from 15 to 49years old who are inhabitants of Bahirdar town . The study also employed individual in-depth interview with key informants who are, one way or the other, believed to be highly concerned with the issue. The paper also attempted to review theories, models and approaches that go in line with the media and HIV/AIDS communication interventions . Finally , the findings of the study showed that the program is found to play no significant role in empowering its target audiences to make open and free public discussion , dialogue and debate about risky human sexual behaviors and other sexuality related issues, which are potentially believed to exacerbate the prevalence of the epidemic in the area. The program fails to consider the socio-cultural context, interests', needs' and levels' of understandings of its target audiences. It is also found out that the existence of one line telephone system in the studio, absence of delay machine, cost of phone calls, inconvenient of broadcasting time and shortage of airtime slot are potential hurdles that affect the program to promote open and free public discussion, dialogue and debate about risky human sexuality and other sexuality related issues on the part of its target audiences.
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    The Practice and Challenges of Situational Leadership in Private High Schools of Addis Ababa
    (Addis Ababa University, 2021-12) Zelalem Tesfaye; Kenenisa Dabi
    The main objective of this study was to investigate the actual practice and challenges of situational leadership in private high schools of Addis Ababa. Specifically, the study examined the leadership exercise in the private high school leadership practices; attempted to identify the challenges faced by private high school leaders and provided possible alternative solutions that might help to control challenges and get better leadership practice. To this end, descriptive research design was used. The research also mixed approach. The study used both primary and secondary sources of data. Purposive sampling technique was employed to select sample schools, school principal’s students and PTSA. In addition, random sampling technique was used for student and teacher respondents. The data analysis and interpretation were carried out by using STATA, percentage, standard deviation and grand mean values as deemed appropriate. Accordingly, it was found out that the practice of situational leadership in private high school was moderate and similar. The findings also indicated that the major challenges in the practice of situational leadership in private high school are lack of trained, experienced and competent human resource, employees’ resistance to change, frequent turnover of employees, lack of incentives for employees, slow decision-making habit, increasing rate of rental buildings and shortage of vehicles. On the basis of these findings the researcher provided such recommendations as high schools leaders should engage in various income generating endeavors involving different stakeholders such as parents, donors and non-government organizations. Key term: - Leadership practice, challenges situational leadership.