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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Start date: 2023Subject: search.filters.subject.SWAT

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Now showing 1 - 7 of 7
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    ASSESSING THE IMPACT OF LANDUSE/LAND COVER CHANGE ON STREAM FLOW AND FUTURE PREDICTIONS OF LANDUSE/LAND COVER CHANGES OF BELES SUB-BASIN, UPPER BLUE NILE BASIN, ETHIOPIA
    (Hawassa University, 2023-08-22) TSEGA MOGES
    Landuse and land cover change drives changes that limit availability of products and services for human, and it can undermine environmental health. Studying impact of landuse/land cover changes on the stream flow is very important for proper basin management. Hence this study investigated the past and potential future land cover changes, and the impact of the past on the stream flow of Beles Sub-Basin using using the Soil Water Assessment Tool (SWAT). To analyze the change that in the study area, satellite images were downloaded for 1987, 2002, and 2019 years and processed using ERDAS Imagine 2014. Then using supervised image classification, the satellite images were classified to agriculture, wetland, forest, shrub land, and urban land. Accuracy assessment was done, and overall accuracy of 86.25%, 88.7% and 87.9%, were achieved for the classified images of 1987, 2002 and 2019 respectively. The net changes of landuse/land cover of the study area from 1987 to 2019 indicated that forest, shrub land and wet land decreased by 4.73%, 10.59%, and 1.10%, respectively, while Agriculture, and Urban, increased by 14.18%, and 2.24%, respectively. The future LULCs of 2035 and 2055 were projected by IDRISI (CA Markov method), and the result indicated an increase of Agriculture 10.94%, Urban 44.04%, where as forest -12.63%, shrub land -11.35%, and wetland -43.61% decreased. Ten parameters identified to be sensitive for the stream flow. Model calibration was carried out using observed stream flow data from (1989-2010) and The validation was performed from (2011-2019). Both results showed good match between measured and simulated stream flow data with R 2 and ENS achieved 0.80, 0.74 for calibration and 0.64, 0.78 for validation respectively. Due to LULCC, the mean annual Stream flow increased by 3.04m3 /s from 1987-2002, and, 2.83m3 /s from 2002-2019 and seasonal flow increased by 12.05m 3 /s, and 5.49m 3 /s in the wet season, while increased and decreased by 2.13m 3 /s and -2.78m 3 /s respectively in the dry season. The surface runoff increased, while groundwater flow decreased from 1987 to 2002 and from the year 2002 to 2019 the mean monthly stream flow increased by 23.29m3 /s for the wet months while for the dry months decreased by 6.31m3 /s. The Stream flow change to different predefined study years indicates LULCC has significant impacts on the stream flow of the study area. To mitigate LULCC, local and national officials in the Beles Sub-Basin should be invited to develop and implement scientific and suitable planning and management plans
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    MODELING OF SURFACE WATER RESOURCES FOR WATER ALLOCATION: A CASE STUDY IN UPPER GIDABO WATERSHED, GIDABO SUB BASIN, ETHIOPIA
    (Hawassa University, 2023-10-28) TAMIRAT SHUKE KITAWA
    The processes of population increase, urbanization, industrialization, and dependency ratio has resulted in a rapid demand increase for water resources in the developing world. Water managers in the watershed of the developing world face the increasingly difficult task of allocating the limited water resources among competing users for fulfilling their demands due to difference in available resources and water demand increment. Water resources management has limited in the Upper Gidabo watershed and there is traditional water allocation are vastly practiced. This was due to lack of sufficient awareness about available water resources and management in watersheds. Understanding the potential and use of surface water in upper Gidabo would help to increase the productivity of Agriculture and other sectors, to improve the traditional water management system. Therefore the objective of this study was to Modeling of surface water resources for water allocation under developed scenarios for maximizing overall benefits without compromising ecological requirements in the Upper Gidabo watershed in Gidabo sub basin. To achieve the aim of this study soil and water assessment tool (SWAT) model was used to determine the available surface water resources of the watershed after sensitivity analysis, calibration and validation of the model by SWAT_CUP sufi-2 algorithm. The simulated result revealed that the total average surface water potential from the watershed was 773.5 MCM annually during the study period (2021). Both the calibration and validation result for Aposto and kolla gauging station showed a good performance with a value of R2 and NSE of 0.83 and 0.65 for calibration and 0.81 and 0.6 for validation in Aposto and 0.79 and 0.62 for calibration and 0.78 and 0.61 for validation in Kolla gauging station, respectively. After this Water Evaluation and Planning (WEAP) model was used to assess water demands. To assess irrigation water requirement of the sixteen (16) crop types CROPWAT 8.0 software was used. After assessing the currently existing demands Different scenarios were also developed to determine the future water demand, and unmet demand from overall time period of 2021-2050, This scenarios namely: reference, population growth and increased water demand scenario was established to determine increasing demands under increasing human as well as Livestock population, agricultural areas and different industrial activities. The current (2021) utilization is about 110.4 MCM for consumptive use and non-consumptive (EFR) use, For EFR 10% considered from available flow to maintain ecological functioning and water resource development in the watershed. The current demands fully met with available flows and for scenarios the assessed total annual water demand may be expected to be 126 MCM, 195.1 MCM and 341.8 MCM for the reference, high population growth, and increased water demand scenarios, except increased water demand scenario the other scenarios is met fully, It is appropriate to shape more effective policies and regulations in the area for effective water resources management in reducing water shortage and achieving downstream water needs in the future
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    QUANTIFYING SURFACE WATER AVAILABILITY AND DEMAND ANALYSIS IN THE POORLY GAUGED CATCHMENTS OF JEMMA SUB-BASIN, ABBAY/UPPER BLUE NILE BASIN, ETHIOPIA
    (Hawassa University, 2023-10-28) SAMUEL ABABU FARIS
    The socioeconomic activities and environmental changes with respect to the spatiotemporal variation of streamflow in the catchment intricates the supply and demand management system. Assessment of the surface water potential and demand analysis at a sub-basin level was aimed at estimating escalating demands of the catchments and meeting the society's needs without causing potential negative consequences on the ecological balance of the catchments. To quantify the surface water availability of the catchments, the soil and water assessment tool (SWAT) model was used after the sensitive analysis, calibration, and validation of the model was done by SWAT-CUP. The annual total demands was anlysed in water evaluation and palanning (WEAP) model after the surface water potenial was quantified. Different‘’what if” scenario was developed to forecast future water demand, supply requirement, and unmet demands in 2022-2035. The model showed the mean annual flow depth in Beressa and Robigumer catchments was 174.4mm and 166.91mm, respectively and contirbutes to 37MCM and 149.05MCM surface water potential, respectively. From the mean annual precipitation recieved in the Beressa and Robigumer catchments, 48% and 43% was lost through evapotransipiration, respectively. The model performace showed satisfactory result with a value of 0.89(R2 ), 0.87(NS), and 0.76(R2 ), 0.74(NS) in calibration, and 0.71(R2 ), 0.70(NS), and 0.72(R2 ), 0.66(NS) in validation in the Beressa and Robigumer catchments, respectively. The CROPWAT 8.0 model was used to determine the irrigation water requirement of selected crops. The total consumptive water demand in 2022 was 11MCM(29.7%) and 8.1MCM(5.4%) of the total surface water potential of the Beressa and Robigumer catchments, respectively. The total water demand in projected irrigation area scenario was 125.64MCM(84.05%) of the surface water potential of the Robigumer catchment in the year 2035. The EFR was significant parameter to maintain the ecological balance of catchments. In the two last scenarios the total water demand were beyond the surface water potential of the Beressa catchment. To mitigate the future water stress and scarcity in the catcments, dopting rainwater harvesting, other potential sources, and integrated water resources management options are importannt
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    ASSESSING THE IMPACTS OF CLIMATE CHANGE ON STREAMFLOW UNDER CMIP6 CLIMATE PROJECTION IN THE UPPER OMO GIBE RIVER BASIN, ETHIOPIA
    (Hawassa University, 2023-03-25) LEMLEM GETNET MOLA
    Climate Change is projected to have an impact on future streamflow in various watersheds. This study examined the impacts of climate change on streamflow in the Upper Omo River Basin using a Soil and Water Analysis Tool (SWAT). Projected climate variables (precipitation and temperature) ensemble of 5 Global Circulation Models (GCMs) were obtained from the World Climate Research Programme (WCRP), downscaled by the SDSM4.2 model and applied under the Shared Socioeconomic concentration pathways (SSP2-4.5) and (SSP5-8.5) scenarios. The downscaled SSPs data cannot be directly used to the hydrological model (SWAT) to simulate flow so, Distribution Mapping bias correction method was selected for this study. SWAT was calibrated and validated before it was used for simulation purpose. The performance measures R2 and NSE for calibration (2000-2013) and validation (2014-2019) were 0.79 and 0.71 and 0.86 and 0.85 respectively. Mann Kendall (MK) trend testing was used to determine if a change is statistically significant and to detect trends in temperature and precipitation. According to RCP4.5 and RCP8.5, the emission scenarios predicted significant increasing temperature, but significant decreasing precipitation. Streamflow was simulated for two consecutive periods from 2020 to 2045 and from 2046 to 2071 for both scenarios and compared with the base period from 2000 to 2019 to explore the impact of climate change on Streamflow. The results indicated that the basin is likely to experience increased temperatures and altered precipitation patterns, whereas overall annual flow was projected to be significantly decreasing under SSP2-4.5 and SSP5- 8.5 emission scenarios in the mid and near future. These changes are likely to have major implications for water resources management in the region, particularly for agriculture, hydropower generation, and ecosystem services. The findings suggest the need for adaptive measures to address these impacts, including improved water management strategies and increased investment in climate-resilient infrastructure.
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    ASSESSMENT OF CLIMATE CHANGE IMPACT ON THE WATER BALANCE OF LAKE HAWASSA WATERSHED
    (Hawassa University, 2023-07-25) KIFLE KARITE ONGOCHO
    Assessing the climatic change impact on the water balance of a watershed is vital to develop sound management plans in current and future periods. The main objective of this study was assessing the climatic change impact on the water balance of Lake Hawassa watershed. The study was focused on the projection of climate variables, assessing the historical and future water balance components, and also evaluating the impacts of climate change on the stream flows of Lake Hawassa watersde. The Soil and water Assessment Tool (SWAT) mode was used for assessing the water balance components and to evaluate the climate change impact on the stream flows of Lake Hawassa catchment. SDSM (statistical downscaling model) was used under General circulation model set up for climate modeling. The water balance components of the watershed were computed in gauged and unguaged catchments. According to the SWAT model result in the gauged catchment, the historical average annual precipitation, surface runoff and the evapotranspiration (ET) were 1068.3mm, 155.11mm and 688.3mm respectively. In 2080 for RCP 8.5 the average annual precipitation, Surface runoff and ET will be 972.15mm, 143.17mm, and 812.19mm respectively. The climate change impact on the water balance components of Lake Hawassa watershed was evaluated for RCPs 2.6, 4.5 & 8.5 emission scenarios in the three time periods (i.e. 2020 (2022- 2040), 2050(2041-2070) and 2080(2071-2099). The result from climate model showed a general increasing trend for maximum and minimum temperatures and decreasing trend for precipitation in all the three time periods for all the three emission scenarios. The impact of climate change on the seasonal stream flows of the watershed will generally increases in the Kiremt season in 2020 and 2050 for all scenarios but decreases in Bega and Belg seasons for all time period in all RCPs. The future annual precipitation, Surface runoff, lateral flow, shallow groundwater recharge and water yield will be decreased up to 9 % and 9.9 % respectively and the increase in ET may reach up to 22% at the end of 2099 for RCP_8.5. Due to climate change the future water availability will be reduced in Lake Hawassa watershed. Therefore, the design and implementation of appropriate adaptation and mitigation strategies to the watershed by the decision makers may reduce the adverse effect of climate change.
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    INSTITUTE OF TECHNOLOGY, FACULTY OF BIO-SYSTEMS AND WATER RESOURCES ENGINEERING, DEPARTMENT OF WATER RESOURCES AND HYDRAULIC ENGINEERING
    (Hawassa University, 2023-10-24) YONAS HAILU WASE
    The goal of this study was to assess the groundwater potential zone in a Deme watershed area of the Omo-Gibe basin, Ethiopia, where data availability was poor. In this study, a number of data from a variety of sources have been used, including climate, stream flow, and spatial thematic layers including land use maps, soil maps, drainage density maps, geology maps, slope maps, lineament density maps, and geomorphology maps. In order to estimate the recharge amount and its spatio temporal fluctuation in the watershed, Soil and Water Assessment Tool model was utilized. At the Orata Alem location within the Deme watershed, several modeling techniques, sensitivity analysis, calibration beginning from 1991 to 2001, and validation 2002 to 2006 periods, were applied. As a result, the results of the calibration and validation phases showed that the model can accurately and reasonably reproduce the stream flow pattern and the various hydrograph responses, as indicated by the Nash-Sutcliffe efficiency(ENS) values of 0.78 and 0.74 and the coefficient of determination(R 2) values of 0.81 and 0.76, respectively. The watershed's mean annual recharge rate is estimated to be 214.5 mm/y, with the northern top section of the watershed experiencing a recharge rate of 233.77 mm/y, the middle of the watershed experiencing a recharge rate of 214.72 mm/y, and the lower part of the watershed experiencing a recharge rate of 194.51 mm/y. Analytical Hierarchical Process was used to rank the various layers based on a pair-wise comparison matrix in order to estimate the final normalized weights of thematic map layers. Groundwater flow direction was determined by the Surfer model. GIS-based Multi-Criteria Decision Analysis was applied for mapping of groundwater potential zones and its results were used to identify three Groundwater Potential Zone: low, moderate and high, with area coverage of 26.3664 Km2 ,744.1776 Km2 and 271.9179 Km2 correspondingly. Around 71.4% of the region has a moderate groundwater potential, and 26.084% has a high potential. Lastly, groundwater well inventory data for 35 wells dispersed around the region were used to validate the Groundwater Potential Zone map in order to evaluate the model's efficacy. The validation results confirmed that 84.44% the study Ground water potential zone match with ground water well points in the Deme watershed, so that the applied approach provides well reasonable results that can help in planning, management and sustainable utilization of the groundwater resources in this water-stressed area.
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    QUANTIFYING SURFACE AND GROUND WATER AVAILABILITY OF THE MEKI RIVER, CENTRAL RIFT VALLEY LAKES BASIN, ETHIOPIA
    (Hawassa University, 2024-08-19) SALAME ABDI AHMED
    Quantifying surface water (SW) and groundwater (GW) availability is crucial for effective water resource management. This study assesses SW and GW in the Meki River sub-basin, central Rift Valley, Ethiopia, by SWAT and MODFLOW models. Integrating SWAT and MODFLOW. This study analyzed hydrological dynamics and groundwater resources for a period 2000 to 2020. SWAT divided the watershed into 18 sub-basins and 86 Hydrological Response Units (HRUs), simulating over 21 years with a three-year warm-up period. The SWAT model, calibrated and validated for 2000–2013, successfully simulated hydrological processes. Model performance was robust, with R² values of 0.76 and 0.85 and NSE values of 0.61 and 0.74, following 1000 simulations during calibration and validation. Critical parameters influencing streamflow included CN2, SOL_K, and GWQMN. Using SWAT-derived GW recharge and evapotranspiration, the MODFLOW-NWT model simulated groundwater flow. Calibration with PEST ensured accuracy, achieving a strong correlation (R² = 0.9922) between observed and simulated groundwater levels across 62 piezometers. Error metrics (RMSE = 9.46 m, MAE = 7.22 m) confirmed model accuracy. Spatial analyses showed heterogeneous groundwater flow influenced by local conditions and SW interactions. River-aquifer interactions revealed significant groundwater discharge to rivers, with daily discharge (91,198.128 m³/day) exceeding recharge (24,866.406 m³/day). The steady-state model showed balanced inflows and outflows, with recharge and river discharge being major inputs. This calibrated model offers a solid framework for managing groundwater resources in the Meki River sub-basin, supporting sustainable water management and planning. Groundwater flow primarily moved from the western escarpment towards the Tora-Koshe-Dugda ridge, influenced by varying hydraulic conductivity. The steady-state model balanced inflows and outflows (40.947 Mm³/year), with recharge (23.5 Mm³/year) and river contributions (9.1 Mm³/year) as key inputs. Evapotranspiration, river discharge, and extraction also played significant roles