Water Resource

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End date: 2025

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    RESPONSE OF WHEAT (Triticum Aestivum L.) YIELD AND YIELD COMPONENTS UNDER DIFFERENT MOISTURE STRESS LEVELS AT GEWANE WOREDA, AFAR REGION, ETHIOPIA
    (Hawassa University, 2021-08-19) ZIYAD RUBE HAMID
    Enhancing water productivity of irrigated crops through Agricultural water management practices is a vital option in water scarce areas. Field experiment was conducted at demonstration site of Gewane Agricultural Technical Vocational and Educational Training College located in Gewane woreda, Afar region, Ethiopia. The objective of this research was aimed to identify optimum moisture stress levels for wheat under moisture stress area of Gewane woreda. Ten deficit irrigation levels namely (45, 50, 55, 60, 65, 70, 75, 80, 85 and 90 %ETc) and the control (100%ETc) irrigation water application were used in whole growing season of wheat (Triticum aestivum L.). Adopted wheat variety Fentale -2 was used as testing crop and laid out in randomized complete block design with three replications. The daily climatic parameters used to estimate ETo were collected from Gewane meteorological station. Daily crop water requirement (ETc) was estimated by multiplying reference evapotranspiration with crop coefficient. Yield and yield components were collected and analyzed using SAS 9.0 statistical software. The analysis of variance showed that, the reduction of water application (moisture stress levels) had a highly significant (p<0.01) effect on growth parameters, yield and yield components except on the number of tillers per square meter and harvesting index as compared to the full irrigation (100%ETc). The result also showed that, the grain yield reduced as the stress levels increased, whereas water use efficiency was increased as the stress levels increased. The highest grain yield of 4472.2 kg/ha was obtained from full irrigation( 100%ETc) which had no significant difference with irrigation water application up to 70%ETc. Whereas the lowest grain yield of 3475.7 kg/ha was recorded from 45%ETc. In terms of water use efficiency, the highest and lowest water use efficiency of 1.32 and 0.82 kg/m3 was obtained from 45 and 100%ETc respectively. Therefore, wheat could be irrigated at 70%ETc to improve water use efficiency without a significant grain yield reduction. Moreover, it could be irrigated at 45%ETc in area where water use efficiency is top priority with compromise of grain yield reduction by 22.28% as result of saved water to irrigate other crops
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    GROUNDWATER POTENTIAL ASSESSMENT USING GIS AND REMOTE SENSING: A CASE STUDY IN MANTHA WATERSHED, OMO-GIBE RIVER BASIN, ETHIOPIA
    (Hawassa University, 2023-05-27) ZERIHUN ZENEBE JEBULA
    In the current study area, the demand for groundwater is increasing. Therefore, the ultimate purpose of this study was to map groundwater potential zones in Mantha watershed using geographic information system and remote sensing. Ten groundwater controlling factors (geology, rainfall, lineament, soil, land use/land cover, geomorphology, slope, and distance to river, elevation, and drainage density) were used to map the groundwater potential zones of the study watershed using remote sensing data. Among these, three layers (geology, geomorphology, and soil) of the study watershed were extracted from existing data, and five layers (slope, drainage density, elevation, lineament, and distance to river) were developed using DEM of 30m*30m spatial resolution. 20 years precipitation data obtained from National meteorology Agency of Ethiopia were converted into areal rainfall using inverse distance weight interpolation method integrated with ArcGIS 10.8 to develop rainfall layer of the study watershed. Landsat8 of the year 2020 was used to map the land use/land cover of the study watershed using supervised image classification with maximum likelihood algorism in ERDAS 2015. Then, all thematic layers were reclassified using literatures and Jenks methods and finally rated in analytical hierarchy process. The results of ten thematic layers data rated in in analytical hierarchy process indicated that the most dominant thematic layers that hold high weight relative to others were- geology (28%), rainfall (16.6%), lineament density (12.9%), and soil (10.3%). Groundwater potential map of the study watershed was obtained by using weights derived from AHP and overlay analysis conducted in arc GIS10.8_ platform. There were four groundwater potential zones mapped in the Mantha watershed, namely, very high, high, moderate, and low. The map result was verified by well data and the result showed strong agreement in each category with 85.7%, 83.33%, 90%, and 100% respectively. The finding of this study indicates that the geographic information system and remote sensing model approach are reliable and can be a reliable prospecting method of groundwater potential zone
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    GIS-BASED SURFACE IRRIGATION POTENTIAL ASSESSMENT: A CASE STUDY IN MUGA WATERSHED EAST GOJAM ZONE, AMHARA REGION, ETHIOPIA
    (Hawassa University, 2021-10-22) ZELALEM ABEZA
    Assessing available water and land for surface irrigation is important for planning their use. The high dependency on rain-fed farming and erratic rainfall require alternative ways of improving agricultural production. The alternative to improve is through development of small scale irrigation schemes by assessing the available suitable land and water resources in sub-basin level. The objective of this study was assessing the land and water resources potential of Muga watershed in East Gojjam Zone for surface irrigation development using Geographic Information System. Identification of suitable land, estimation of available river flow, and determination of irrigation water requirement were the main steps that were followed. The land irrigation suitability factors considered were: slope, soil, land use/land cover, and river proximity. Estimation of river flow in the six manually added outlets was conducted by simulation after calibration and validation were carried out with the observed flow of gauged river using Soil and water assessment tool. The commonly cultivated crops in the area maize, onion and potato were selected, and the irrigation water requirements of these crops were determined using the CROPWAT8.0 model. Comparison between gross irrigation water requirement of the selected crops for the identified suitable land with simulated river flow at the area of the selected site was carried out. Overall, the weighted overlay analysis of these factors gave a suitable land among river sub-basin as G/muga 560ha, E/muga 3057ha, Bora 670ha, Gibstawit 404ha, and Genet 241ha. Mean monthly flow of 11.4m3 /s were determined at the watershed. A total of 3443ha (5.1%) was found to be potentially suitable for the development of surface irrigation project from a total watershed area of 67535ha. In conclusion, the irrigation potential of the area could be increased either by harvesting rainwater or using groundwater.
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    PERFORMANCE EVALUATION OF STORMWATER DRAINAGE SYSTEM OF BEDELE TOWN
    (Hawassa University, 2020-10-24) YEROSAN KEBEDE AYANA
    Various factors can degrade the drainage system and reduces its performance. As the role of drainage infrastructure is very high in preventing urban floods, their performance should be monitored and quantified. This study aimed to assess the performance of stormwater drainage systems in Bedele Town. Primary and secondary data were used in this study. The catchment that contributes runoff was delineated using ArcGIS 10.4 software. The Stormwater Management Model (SWMM 5.1) was used to simulate the peak flow rate and water level in the drainage canals by considering the current land use. The intensity duration frequency (IDF) curve was developed by using the Log-Pearson Type III. The peak runoff for 10-year and 25-year return periods was estimated by using the Rational Method. The condition of the existing drainage system was assessed and poor solid waste management, lack of well-connected drainage lines, poor liquid waste disposal, and the existence of fully uncovered areas in the town with drainage structures were identified to be the drainage problem of the Town. From the total area of Bedele Town, 41.1% is uncovered with the drainage systems. The total peak runoff generated from this study area is 15.59 m3/s and the average velocity was 2.5m/s for a 10-year return period. The result from the Rational method as well as SWMM 5.1 shows there is an overflow problem in this study due to the presence of drainage canals with insufficient capacity to carry the runoff generated from this catchment. For a sustainable drainage system, the appropriate use of hydrological analysis, hydraulic design, and stream morphological study should be implemented before carrying out the construction of drainage structures for they were not considered during the construction of the drainage system of the Town. Regular maintenance and frequent clearance of drainage lines, proper integration between roads and drainage structures, provision of additional drainage canals, and improved stormwater management were recommended to solve the stormwater drainage problem of the Tow
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    ASSESSMENT OF SURFACE WATER QUALITY AND POLLUTION CONTROL STRATEGIES USING QUAL2Kw MODEL: A CASE STUDY OF TIKUR WUHA RIVER; HAWASSA, ETHIOPIA
    (Hawassa University, 2023-10-26) YARED TEMESGEN
    River water pollution is caused by both natural and artificial activity, such as waste generated from urban area and agricultural lands. The water quality model using QUAL2Kw was conducted to assess the water quality status of Tikur Wuha River and pollution control strategies in Hawassa, Ethiopia. Water samples from this river were collected on March 2023 at different monitoring stations along the river, and their quality was analyzed. The study result indicated that all the measured parameters satisfied the guidelines of the WHO and Ambient Environment Standards for Ethiopia except BOD5, TSS, and PO4 -3 in the study period. The concentration of DO were meet the permissible limit and two sampling station were below the minimum limit. The measured water quality of the river was appropriate for agricultural activity at all sampling points. The model was applied to simulate the water quality parameters such as flow rate, water temperature, EC, DO, BOD5, pH, TSS, ammonia-N, nitrate-N, and phosphate. The model represented the measured data quite well with some exception. In this study, a stream water quality model, Q2Kw, was used to predict the river water quality using the data collected in dry season. The results from the calibrated model indicate that the model was able to appropriately predict the pollution of the river with |PBAIS| and R 2 values of 1.02% (0.999), (0.65), 8.87% (0.6), and 0.71%, respectively, for temperature, DO, EC, and pH. The model can be applied successfully to generate future scenarios for the study area and applicable to assess the effect of various pollution controls and supporting in-stream measures on key water quality parameters. In general, the study results indicate that proper waste management should be adopted to prevent the continued deterioration and improve the water quality condition of the Tikur Wuha River
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    COMPARISON OF SWAT AND WEPP FOR MODELING ANNUAL RUNOFF AND SEDIMENT YIELD AND QUANTIFCATION OF NUTRENT LOSS IN AGEWU MARIYAM WATERSHED, NORTHERN ETHIOPIA
    (Hawassa University, 2022-10-22) YALELET ABIE WORKU
    Unevenly heavy rainstorms during the rainy season create runoff and soil erosion which affects soil fertility and production, especially in northern Ethiopia. In this study soil and water assessment tool (SWAT) and geographic water erosion prediction project (GeoWEPP) were applied to compare estimation of annual runoff and sediment yield and quantification of nutrient loss in Agewu-Maryam watersheds eastern Amhara, region, Ethiopia. To run both models, need spatial and temporal data distribution is required as an input. The soil textures and other selected soil properties were determined in the field and the laboratory and a soil map were derived from the digital soil map of the world. A land-use map was prepared based on manually digitizing from Google earth image. A Digital Elevation Model of the watershed was used for delineating the watershed and preparing a slope map. ArcGIS 10.4 was used for both models for basic interface for further analysis. During each runoff event, runoff samples were collected and the sediment concentrations were analyzed in the laboratory. The simulation result of long-term (24-year) average means annual runoff and sediment yield from WEPP and SWAT models were estimated. The results were performed well as indicated by R 2 0.86 and 0.91 and with NSE 0.54 and 0.71 for monthly runoff were satisfactory for SWAT and WEPP models compared with observed value respectively The estimated average mean annual runoff and sediment yield at the outlet of the watershed was 65.54mm and 146.14mm and 43t/ha/yr and 41.7t/ha/yr respectively for WEPP and SWAT models. The t statics result shows that there is no statistically significant difference with p-value (0.97 for runoff and 0.98 for sediment) between the two models' simulation results. Some of the Sub watershed were identified and prioritized as more susceptible to soil erosion and give more attention first to this area for reducing runoff and soil erosion. The total nutrients loss within the suspended sediment were 33.74kg/ha/yr N,6.79kg/ha/yr P, 642.5 OM kg/ha/yr, and 1.52 K for the watershed. Hence SWAT and WEPP models were well suited for the estimation of annual runoff and sediment yield. The sediment yield simulated from both models was high which was alarming and far beyond the soil loss tolerable rate. Therefore, the result of the model could be used as a decision-making tool
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    ASSESSING FARM WATER MANAGEMENT AND INFRASTRUCTURAL PERFORMANCE OF KOGA IRRIGATION SCHEME; IN THE CASE OF INGUTI UNITE
    (Hawassa University, 2020-11-20) WUBLIKER NEGESE YIHUNE
    Irrigation scheme performance was assessed to evaluate the field water managements and its infrastructural performance .The principal objective of this study was to evaluate field water management and infrastructural performance of Koga irrigation scheme specifically Inguti unit using selected internal performance indicators. Moreover, an institutional support service was evaluated to understand how the scheme is being administered. Field data such as discharge, soil moisture content, and soil physical properties and infrastructures performance were collected. Field surveys and group discussions among the farmers/beneficiaries and Water User Associations (WUA) was also conducted to evaluated existing situation of the support service in the scheme and its performance of WUA. From house hold survey 493 users55 beneficiaries were selected by stratified random sampling. Field surveys and group discussions among the farmers/beneficiaries and Water User Associations (WUA) was also conducted to evaluated existing situation of the support service in the scheme and its performance of WUA. From house hold survey 493 users55 beneficiaries were selected by stratified random sampling. Secondary data such as crop data, climate data and design documents were collected from National Meteorological agency and Koga Irrigation Project office. CROPWAT 8.0 model, GIS and Microsoft office (excel and word) were used for data analysis and documentation in this thesis. Average conveyance efficiency values ranged from 81 to 86.5% for lined (secondary and tertiary canals) and about 64% for unlined tertiary canals. The maximum water loss observed was 0.19 and 0.21l/s/m on lined (secondary and tertiary) canals respectively. And also the maximum water loss observed in unlined tertiary canals was 0.26l/s/m. The average field storage efficiency was found to be 78.9 % and the average field water application efficiency was 53.5%. Average values of the scheme water level ratio, cropped area ratio and infrastructural effectiveness was 85.8%, 94% and 96.2% respectively. The performance of the irrigation scheme was weak due to poor field water managements as indicated above. This might be attributed due to a number of factors observed at field such as illegal water abstraction, unequal distribution of irrigation water, sedimentation of canals and inadequate operation and canal maintenance. Field survey indicates sedimentation, cracking and weeds problems in the lined canals. The overall efficiency of scheme in the Inguti unit was found to be 46.3%. This implies organizational set up and legal enforcement of bylaws and institutional support service was weak to fully maintained and managed irrigation water in the fields
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    IMPACT OF CLIMATE CHANGE ON LOCAL HYDROLOGY: A CASE STUDY IN AGULA’E WATERSHED, TEKEZE BASIN, NORTH ETHIOPIA
    (Hawassa University, 2017-10-16) TSEGAY AREGAWI ATSBAHA
    Climate change, nowadays, has significant impact on the water resource system of an area. This study was conducted in Agula’e watershed, Tekeze river basin, Ethiopia, using Water and Energy Transfer through Soil, Plants and Atmosphere (WetSpa) hydrological model and General Circulation Model (GCM) aiming at estimating the impact of climate change on water availability of the study area. By making proper calibration, precipitation and temperature outputs of HadCM3 coupled atmosphere-ocean GCM model for A2a (medium to high) and B2a (Medium to low) SRES emission scenarios were downscaled using Statistical Downscaling Model (SDSM). In 2020s, precipitation, maximum temperature, minimum temperature and potential evapotranspiration will increase by 1.03%, 0.55%, 0.09% and 2.08% for A2a emission scenario and 1.84%, 0.42%, 0.1% and 2.14% for B2a emission scenario respectively. In 2050s, it will be expected an increment trend in precipitation, maximum temperature, minimum temperature and potential evapotranspiration by 0.8%, 1.63%, 0.12% and 3.13% for A2a emission scenario and 3.06%, 1.19%, 0.10% and 2.95% for B2a emission scenario. In 2080s, precipitation, maximum temperature, minimum temperature and potential evapotranspiration will increase by 1.05%, 3.17%, 0.15% and 4.63% % for A2a emission scenario and 1.35%, 1.97%, 0.13% and 3.65% for B2a emission scenario. In the future period, the overall trend in aerial mean maximum temperature, precipitation, and potential evapotranspiration show positive increment by 2.5%, 0.96%, and 3.28% under A2a and 2.05%, 2.12% and 2.91% for B2a emission scenario respectively. Minimum temperature will not show significance change for both emission scenarios. The model showed that precipitation and actual evapotranspiration results in average increment trend by 1.03%, 0.78% and 1.03% for A2a scenario and 1.93%, 3.05% 1.34% for B2a scenario in 2020s, 2050s and 2080s time horizons respectively. In the future time horizons, actual evapotranspiration will be increased by 6.96%, 7.01% and 7.42% under A2a scenario and by 8.49%, 9.91% and 8.25% for the B2a scenario. The overall trend of precipitation and actual evapotranspiration value will increase by 0.95% and 7.13% under A2a emission scenario and 2.11% and 8.88% under B2a emission scenario respectively. Surface runoff will generally has decrement trend in all the future periods and will averagely decrease by 71% for A2a and70% for B2a emission scenarios
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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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    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