Institute of Technology

Permanent URI for this communityhttps://etd.hu.edu.et/handle/123456789/66

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

Browse

Filters

20233

Settings

Subject: search.filters.subject.stream flow

Search Results

Now showing 1 - 3 of 3
  • No Thumbnail Available
    Item
    ASSESSMENT OF THE RUN OF THE RIVER HYDROPOWER POTENTIAL AT THE DOWN STREAM OF KOKA DAM AND FORECASTING THE LEVEL OF FLOODING AT SELECTED SITE (CASE STUDY OF AWASH RIVER BASIN, ETHIOPIA)
    (Hawassa University, 2023-10-26) ASHENAFI AYZA ASELE
    Energy demand is increasing exponentially. This is because of rapid population growth, urbanization, the higher standards of living, industrial and agricultural expansion. Nevertheless, the available energy supply is not reliable due to sedimentation problem. So, it is advisable to use the nearby available natural resources (i.e. river and suitable topography) for potential assessments without adverse effect to cope with increasing and diversified energy demands. This study aims to investigate the assessment of river run of hydropower potential at 50km downstream of Koka Dam. To achieve the goal, Stream flow data were collected from 1991-2016 and height information was quantified from contour map and 3D spatial analyst tool in ArcGIS. Initially, the study was identified three possible potential sites and from these sites; site one was selected as the most prioritized site using MCDA method. The study included the Flood level forecasting at mostly prioritized site for further precaution using HEC-GeoRAS for preprocessing of geometric data and HEC-RAS for post processing of hydraulic modeling. Following the aforementioned model, methods and data the study computed the theoretical power at site one was (8981kw and 4197kw), technical power was (6960kw and 3253kw) and the annual energy output was (60.9GWh/year and 28GWh/year) are the maximum and minimum power at Q30 and Q95 respectively. The most preferred site had dependable flow of 19.71m3/s and is occur 95% of the year and the design flow was 42.17m3/s and is occur 30% of the year. The flood inundation area and the maximum flood depth at mostly prioritized river station 1100 where the study starts head measurement (i.e. upstream full reservoir level) and around 1km upstream of R.S. 1100 (i.e. at R.S.2050) were (145.79m 2 , 4.96m) and (204.09m 2 , 5.62m) respectively for 100 year return period. The validation of spatial information for site one tested were 0.71 for RMSE and hydraulic model performance for R.S.1100 and R.S.2050 were (0.7, -8.29 and 0.97) and (0.83, 5.92 and 0.96) for ENS, PBIAS and R for return period of 100 year and show the applicability of the model was good. To encapsulate we can get the site at 50km downstream of Koka Dam that have the capacity to produce annual energy of 60.9GWh/year. Consequently, it is possible to minimize the problem of highly increased and diversified electric demands at the target area. Hence, it is recommended that the government at national as well as local level or any other agency should look over it in detail and finding to implement thorough investigation of the area
  • No Thumbnail Available
    Item
    MODELING HYDROLOGICAL RESPONSES TO LAND USE AND LAND COVER CHANGE IN MEGECHA RIVER CATCHMENT OMO-GIBE BASIN, ETHIOPIA
    (Hawassa University, 2023-10-26) BEAKAL YISEHAK ASHENGO
    Land use/ land cover change has been one of factors responsible for altering the stream flow of the watershed on the Megecha River Catchment OMO-GIBE basin leading to impacting river flows. The study mainly focused on to evaluate the impact of land use land cover change on streamflow. Land use change detection was done using remote sensing techniques and the maps were processed through maximum likelihood algorithm of supervised classification using ERDAS Imagine 2014 and ArcGIS 10.4 software. A physical based, semi –distributed hydrological model, SWAT was used to investigate the impact of land cover change on streamflow, of Megecha River Catchment OMO-GIBE Basin. From the land cover change analysis result it was found that there has been a substantial decline of sparse and moderate forest, grass land, bare land and water body. The cropland in the watershed increased from 68.80% in 1996 to 71.13 in 2016. Similarly shrub land and settlement shows increase. This is mainly because of the population growth that caused the increase in demand for new agricultural land and rural settlements which in turn resulted shrinking on other types of land use and land cover of the area. Results have revealed that there is substantial increase in surface runoff volume from 94.34mm to 125.97mm for the LULC map of year1996 and 2016 respectively. The model evaluation statistics for stream flow provided a very good result since NSE >0.75 and R2 >0.75. The change in LU/LC ensued in augmented stream flow and in which the expansion of agriculture has also resulted an increase of surface run off, but decreased the ET of river catchment. Therefore, curving the trends of LU/LC towards increasing vegetation covers is very important so as to reduce the seasonal flow and surface runoff, on the other hand to increase ground water flow. One way of increasing vegetation cover in the river catchment is through controlling the expansion of agriculture at the expense of other land covers and improving the productivity of existing farm lands through the provision of improved production inputs and livelihood diversification
  • No Thumbnail Available
    Item
    EVALUATING THE PERFORMANCE OF SWAT AND HEC- HMS MODELS ON RAINFALL-RUNOFF ESTIMATION AT THE GREAT AKAKI RIVERWATERSHED, ETHIOPIA.
    (Hawassa Unversity, 2023-10-17) HENOK GEZAHEGN MULUNEH
    The present study was conducted to examine the accuracy and applicability of the hydrological models Soil and Water Assessment Tool (SWAT) and Hydrologic Engineering Center (HEC)- Hydrologic Modeling System (HMS) to simulate stream flow. Models combined with the ArcGIS interface have been used for hydrological study in the Great Akaki River watershed. The critical focus of the stream flow analysis was to determine the efficiency of the models when the models were calibrated and optimized using observed flows in the simulation of stream flow. Daily weather gauge stations data were used as inputs for the models from the 1995-2017 periods. Other data inputs required to run the models included land use/land cover (LU/LC) classes resulting from Map agency and related offices, soil map and digital elevation model (DEM). For evaluating the model performance and calibration, daily stream discharge from the catchment outlet data was used. For the SWAT model calibration, ALPHA_BF (Base flow alpha factor (days), curve number (CN) and GW_DELAY(Groundwater delay(day)) are identified as the sensitive parameters. SCS.lag (MI), Curve number(AMC_II) and Initial abstraction (Ia) are the significant parameters identified for the HEC-HMS model calibration. The models were subsequently adjusted by auto calibration for 1995-2010 to minimize the variations in simulated and observed stream flow values at the catchment outlet (Aba Samuel). The hydrological models were validated for the 2011-2017 period by using the calibrated models. For evaluating the simulating daily stream flow during calibration and validation phases, performances of the models were conducted by using the Nash-Sutcliffe model efficiency (NSE) and coefficient of determination (R2). The SWAT model yielded high R2 and NSE values of 0.85 and 0.82 for daily stream flow comparisons for the catchment outlet at the calibration and validation time, suggesting that the SWAT model showed relatively good results compared to the HEC-HMS model. Also, under modified LU/LC and ungaugedstream flow conditions, the calibrated models can be later used to simulate stream flow for future predictions. Overall, the SWAT model seems to have done well in stream flow analysis for hydrological studies.