Institute of Technology

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The Institute of Technology focuses on education, research, and innovation in engineering, technology, and applied sciences to support sustainable development.

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    STREAMFLOW RESPONSE TO CLIMATE CHANGE ON TIKUR WUHA SUB WATERSHED, RIFT VALLEY BASIN, ETHIOPIA
    (Hawassa University, 2018-10-23) BROOK LEGESE DADHI
    Climate changes alter regional hydrologic conditions and results in a variety of impacts on water resource systems. Such hydrologic changes will affect almost every aspect of human well-being. Simulation models of watershed hydrology and water quality are extensively used for water resources planning and management. This study aims to assess the streamflow response to Climate Change on Tikur Wuha Sub-watershed, Rift Valley Basin of Ethiopia. In the study the daily hydro-meteorological data values for the baseline period of 1981-2005 were used. Historical Representative Concentration Pathway (RCP) data along with observed data of precipitation and temperature were used for extraction and bias correction using CMhyd tool. After evaluation of bias correction methods using residual plot, and RMSE, MAE and RE, the downscaled climate data such as, RCP4.5 and RCP8.5 scenarios was used for the future period assessment. Soil Water Assessment Tool (SWAT) models were used to assess the streamflow response to Climate Change. Calibration and validation of the model output were performed by comparing simulated streamflow with corresponding measurements from the Tikur Wuha outlet for the periods of 1992-2001 for calibration and 2002-2005 for validation using SWAT-CUP(SUFI-2). The model calibration and validation results shows a good agreement with the observed flow with the coefficient of determination 0.79 and 0.86, and a Nash Sutcliffe efficiency was 0.56 and 0.64, respectively. The result of projected temperature reveals a systematic increase in all future time periods for both RCP 4.5 and RCP 8.5 scenarios, and for all considered period whereas the projected result of precipitation was inconsistent throughout all future time periods and for both RCP 4.5 and RCP 8.5 scenarios. The dynamically downscaled daily climate variables (precipitation and temperature) were used to simulate future projections of streamflow. Streamflow projections for future time periods showed that mean annual streamflow may increase by 15.43, 23.48, and 25.42% in 2020s, 2050s, and 2080s, respectively, from the baseline period for RCP 4.5 scenario, whereas for RCP 8.5 scenario, it will be expected to increase by 29.58, 34.20, and 38.72% in 2020s, 2050s, and 2080s, respectively. The model simulations considered only future climate change scenarios assuming all spatial data constant. Therefore, future study need to consider impact of land use/cover change on the sub-watershed for future sustainable development plan.
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    THE EFFECT OF CLIMATE CHANGE ON URAN DRAINGE: CASE OF BISHOFTU CITY DRAINAGE
    (Hawassa University, 2018-07-14) ABREHAM AMDE GEBRESELASSIE
    Climate change is a reality that planners and designers of drainage infrastructures must consider. Therefore, the risk should be investigated and quantified properly. The objective of this thesis is to investigate the effect of climate change on Urban Drainage having the case of Bishoftu city drainage. Projection of the future climate is done by using CMIP5 climate model outputs of RCP4.5 and RCP8.5 scenarios and downscaled daily rainfall and temperature data of CMIP5. The future climate projection analysis was done by partitioning the coming 50 years in two periods which are (2020-2040) and (2051-2070) and the 1994-2013 is taken as the base line period. These climate scenarios data were bias corrected for serving as input to the SCS for impact analysis. Using Easy fit software, the rain fall data was fitted to Gumball distribution for the quantile estimation. The quantile estimation of 2, 5, 10, 25, 50 and 100 years return period for the site were found to be 47.818, 60.043, 68.137, 78.363, 85.95, 93.481, 110.884 and 118.365. Respectively. The study area which are Kalhiwet church area and the market area water shed area of the drainage design was done. The hydrologic analysis of rain fall run off is computed by using modified SCS method and the hydraulics parameter is computed by 4.2 Hydraulic tool box software for the two catchment area with RCP4.5 and RCP 8.5 Scenarios of the two time horizon of 2030s and 2060s. Finally the design discharge amount is change in Market area by RCP 4.5 in 2060 is change by 63.3% and Minimum 18.64% in RCP 4.5Average design discharge, channel width and depth will increase up to 60.8% Max and 16.9% Min , 29.9% Max and 6.05% Min, and 20.21% Max and 6.7% Min depth is changed in KHC respectively. And for the design discharge of market area Max 63.3% and Min 18.64%, the width of channel is changed by 31.16% Max and 8.17% Min, and also the depth of the channel 32.22% Max and 9.09% Min also change. Therefore, the consideration of climate change on drainage is important
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    IMPACT OF CLIMATE CHANGE ON THE HYDROLOGY OF UPPER BLUE NILE RIVER BASIN: A CASE STUDY IN TANA SUB-BASIN, ETHIOPIA
    (Hawassa University, 2020-11-06) SURAFEL ARAGAW LAMESGIN
    Climate change is one of the serious issues in the word including developed and developing countries like Ethiopia. Tana Sub-Basin is located in the upper Blue Nile River basin . The aims of this study was to evaluate the impact of climate change on the hydrology of Upper Blue Nile River basin of Tana sub-basin in the northwest of Ethiopia. Dynamically downscaled climate model precipitation and temperature outputs were obtained from CORDEX-Africa program RCP4.5 and RCP8.5 by Regional Climate Model. The climate data has significant bias and bias correction was done by using CMhyd tool before used as input to the impact analysis. The analysis was performed in two future projection, 2020-2049 and 2050-2079 considering the reference baseline period 1988-2017 with both RCPs. Minimum temperature changes for RCP 4.5 raised by 0.26°C to 1.10°C and 0.45°C to 2.77°C, and for RCP8.5 0.15°C to 1.58°C and 1.02°C to 2.68°C Mean monthly minimum temperature change for 2020 – 2049 and 2050 – 2079. and Maximum temperature changes for RCP 4.5 and increase by 0.25°C to 1.6°C and 0.1°C to 1.91°C and for RCP 8.5 0.11°C to 1.92°C and 0.19°C to 2.17°C for 2020 – 2049 and 2050 – 2079 time periods with reference to the baseline periods respectively. And also, the mean monthly precipitation change will be increased and decreased by 2.09% to 23.95 % and 30.73% to 47.46% for both RCP4.5 and RCP8.5 scenarios respectively. The SWAT models were used to assess the streamflow response to climate change. Calibration and validation of the model output were performed by comparing simulated streamflow with observed flows from Tana Sub Basin (Blue Nile River outlet at Bahirdar gauging station) for the periods 1988-2001 for calibration and 2002-2008 for validation using SWAT-CUP(SUFI-2). The model calibration and validation result shows R2 and NSE of 0.87 and 0.84 and 0.61 and 0.6 during calibration and validation respectively. Finally, climate change impact on monthly streamflow was evaluated by relating base period stream flow with the future flows for the 2020-2049 and 2050- 2079 for both RCP4.5 and RCP8.5 scenarios. The future streamflow result shown increasing and decreasing change for both RCP4.5 and RCP8.5 scenarios. Hence, the increased and decreased stream flow in the basin may have a significant contribution for the sustainability of existed and undergoing water development projects