Water Resource

Permanent URI for this collectionhttps://etd.hu.edu.et/handle/123456789/71

Browse

End date: 2019Has files: Yes

Search Results

Now showing 1 - 10 of 56
  • No Thumbnail Available
    Item
    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
  • No Thumbnail Available
    Item
    IMPACT OF LAND USE/LAND COVER DYNAMIC ON HYDROLOGY REGIME: A CASE STUDY IN THE UPPER BARO BASIN, GAMBELLA, SOUTHWEST ETHIOPIA
    (Hawassa University, 2019-03-11) Tewodros getu engida
    The principal driving forces for land use/land cover change(LULCC) are rapid increases of population and forest clearing. Those are important factors that influence the hydrological condition of a catchment. Land use/land cover change can also result in change of flood frequency, increase peak flows, base flow, and annual mean discharge. To reverses such kind of problems, assessment of hydrological condition in relation to LULC and finding solution at a watershed level is necessary. The objective of this study was to assess the impacts of LULC change on the hydrology of Upper Baro Basin using Soil and Water Assessment Tool model. The LULC change analysis was performed by using supervised classification method using ERDAS imagine 2014. The accuracy of the classified maps was assessed using error matrix of each selected period. Consequently, 92.14%, 94.63% and 95.63% were found for LULC classification of 1987 ,2002 and 2017 study years, respectively. The result show that there was a drastic decreased of grass land by15.64 % and an increase of agricultural land and settlement by 18.01% and 13.01%, respectively over period. SWAT model was adopted to perform simulation of the main hydrological component in order to finding the effect of LULCC using in 1987,2002 and 2017 and also calibration, validation and uncertainty analysis were performed using sequential uncertainty fitting (SUFI-2). The result showed that there was a reasonable agreement between observed and simulated streamflow with coefficient of determination (R2) and Nash-Sutcliffe efficiency values 0.87 and 0.76 for calibration periods 1990-2002 and 0.77and 0.72 for validation period of 2003 to 2010 respectively. Further, the model was predicting the impact of LULC change on streamflow for period 1987,2002 and 2017. Evaluation of hydrologic response unit (HRU) due to LULCC showed that mean monthly streamflow was increased by 35.8% in wet months and decreased by 21.05% in dry months between the years 1987 and 2002. While betwee 2002 and 2017, it was increased by 47.1% and 3.49% for wet and dry months, and the year 2017 and 1987, it was increased by 82.9% and 15.54% for wet and dry months respectively. InVEST model was used to assess the total soil loss potential for each LULCC, these result show that increased from 276462.8 in 1987 to 391741.2 ton/year in 2017 and the mean annual soil loss was also increased from 67.67ton/ha/year in 1987 to 70.84ton/ha/year in 2017. The trend of soil loss and sediment export indicates that an increase in LULCC. Deforestation and soil erosion problems need to be give attention urgently to maintain the stability and resilience of the ecosystem
  • No Thumbnail Available
    Item
    ASSESSMENT OF RURAL COMMUNITY WATER SUPPLY SCHEMES SUSTAINABILITY AT SHEBEDINO WOREDA, SIDAMA ZONE, SNNPR, ETHIOPIA
    (Hawassa University, 2018-10-27) WONDWOSEN ADMASU
    In developing country there is a problem of water supply schemes sustainability due to damage of functional water supply schemes with different reasons through their service period. This situation is also observed in Ethiopia with in all states and woredas. Shebedino woreda found in sidama zone, SNNPR State has a visible problem in this regard. This study was conducted to assess the sustainability of water supply schemes in Shebedino woreda(study area). The assessment was focused on the functionality of water supply schemes; examining the sustainability of water supply schemes through technical, financial, organizational, social, environmental factors, and community perception within four sampled kebele and 15 water supply schemes of the study area. For this research purpose primary and secondary data were used. Data was collected focused on House to House interview, Field observation, Focus Group Discussion and Key Informant interview with organized questions. Field observation was conducted .The data was analyzed by descriptive analysis method. From finding the nonfunctional water supply scheme of study area was 33.58 % which is greater than from SNNPR and national level. Technical, financial, organizational, social, environmental factors and community perception have major contribution in the sustainability of water supply schemes. Among the reasons for frequently failed of water supply schemes, lack of spare part has taken the large percentage which is 47.78% and the second large proportion is poor management which is 31.67%. Inadequate budget were contributed for insecurity of sustainability of water supply schemes .The study result shows that more emphasis is not given for community participation in planning and technological selection. Large percentage of finance was allocated for newly constructed water supply schemes by NGOs 79.2%, but government and community have low contribution. Community participation, technical factors and organizational management are the major parts need more emphasis to ensure the sustainability of water supply schemes. It was found that even though the community has high willingness in contribution for the sustainability of water supply schemes, but there is low practice of community involvement. This positive attitude has significance in the sustainability of water supply schemes but need more improvement
  • No Thumbnail Available
    Item
    MODELING THE IMPACT OF LAND USE/LAND COVER AND CLIMATE CHANGE ON THE HYDROLOGICAL BEHAVIOR OF ANDASA RIVER CATCHMENT BY USING SWAT
    (Hawassa University, 2017-12-11) NEGUSU TAREKEGN
    Andasa River Catchment is one of the tributary of Abay River located in Upper Blue Nile Basin. In the catchment climate change and land use impacts were not well studied and quantified yet. Hydrological modeling of catchments is essential for future water resource development programs to provide information for decision makers and planners. For hydrological model Simulation SWAT model was used after calibrating and validating the sensitive parameters of the catchment. The calibration, validation and uncertainty estimation were done by SWAT-CUP in particular by SUFI2 project. The model has very good performances to use for the catchment and further, the model is capable to simulate climate change impacts and land use scenarios. Following SWAT model setup, future climate change scenarios were developed for the catchment and their subsequent impact on the water balance were estimated. This study used HadCM3 GCM model from fourth assessment report of the IPCC under A2 (high) and B2 (low) emission scenarios and CanESM2 model from fifth assessment report of the IPCC under RCP4.5 and 8.5 representing the maximum and minimum condition of CO2 emissions. The coarse GCM resolution was down-scaled by Statistical Downscaling Model (SDSM). The model used to downscale the station level weather variables temperature (minimum and maximum) and rain fall called predictand with the coarse GCM predictors by the principle of multiple regression for the future till 2099 /2100. The future downscaled weather variables were divided into 3 periods; 2013-2042, 2043-2072, and 2073-2099. The change in temperature (˚C) and rain fall (%) is calculated for the three periods in comparison to the base period (1993-2012). The climate projection result indicated increasing monthly temperature and decreasing tendency of rain fall under all scenarios. However, all scenarios agreed in increasing temperature and decreasing rain fall trends in the three periods while averaged. The change in temperature (˚C) and rain fall (%) is introduced to SWAT to simulate the water balances. Based on SWAT model simulation significant reduction of stream flow was observed under almost all scenarios in all future periods. Moreover land use scenarios were developed for the base period (1991-2012) and for future period (2013-2042). Best case scenario (afforestation and conservation) were developed for the two periods. Agricultural land expansions considered as worst case scenario. And their respective hydrological simulation indicated that in best case scenario significant increase in infiltration was observed. Hence, it enhances base flow and maintains stable dry season flow in comparison to worst case scenario
  • No Thumbnail Available
    Item
    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.
  • No Thumbnail Available
    Item
    PERFORMANCE EVALUATION OF WOSHA AND WERKA IRRIGATION SCHEMES IN WONDO GENET DISTRICT, SNNPRS, ETHIOPIA
    (Hawassa University, 2018-08-12) HENOK TESFAYE CHARINET
    Expanding efficient irrigation development on various scales is one of the best alternatives to provide reliable and sustainable food security. However, many irrigation schemes in developing countries in general and particularly in Ethiopia are performance below capacity. Performance evaluation of irrigation schemes plays a fundamental role in improving irrigation system of a scheme by identifying where the critical problems occurred. Evaluation of irrigation schemes carried out at Wondo Genet SNNPRS, Ethiopia. The primary objective of evaluating Wosha and Werka irrigation schemes using internal and external indicators were to evaluate their performance and suggest possible interventions to enhance their capacity. Internal indicators including conveyance, application, water storage, water distribution uniformity efficiency, and deep percolation ratio were used at the head, middle and tail reach of each scheme. Moreover, external indicators of agriculture output, water supply, water delivery capacity and physical indicator were used for evaluating the schemes. The results showed that the conveyance, application, storage, distribution efficiency of 55.6, 48.2, 89.8 and 91.7%, respectively were found at Wosha irrigation scheme whereas 43.0, 59.0, 87.2 and 91.4%, respectively at Werka irrigation scheme. The agricultural output performance such as OPUIA, OPUCA, OPUIS, and OPUWC were 4213.97 US$/ha, 8732.29 US$/ha, 1.18 and 0.32, respectively at Wosha irrigation scheme and 5840.34, 8534.19, 1.77 and 0.42 respectively for Werka irrigation scheme. Water supply indicators such as RIS and RWS were 0.64 and 0.71, respectively for Wosha 0.48 and 0.55, respectively for Werka irrigation scheme. The result indicates that water delivery capacity of Wosha and Werka irrigation schemes were 1.56 and 1.32, respectively. Physical indicators revealed that irrigation ratio of 0.89 and 0.78 and sustainability of irrigated area of 2.07, and 1.46 were found at Wosha and Werka irrigation schemes. Among the internal indicators, application efficiency was very low especially at Wosha irrigation scheme due to higher water loss through deep percolation. The overall efficiency was also below the desired level, where 26.8 and 25.4 %, respectively realized at Wosha and Werka irrigation schemes. Based on the above observation, adoption of water saving practices such as deficit irrigation, surge and cutoff application to improving application, conveyance and distribution systems can enhance crop productivity per unit irrigation water
  • No Thumbnail Available
    Item
    EFFECT OF DEFICIT IRRIGATION ON YIELD AND WATER PRODUCTIVITY OF ONION (Allium cepa L.) UNDER CONVENTIONAL FURROW IRRIGATION SYSTEM IN BENNATSEMAY WOREDA, SOUTHERN ETHIOPIA
    (Hawassa University, 2019-10-22) TADESSE MUGORO LEBISO
    Enhancing water productivity is an important strategy for addressing future water scarcity in arid and semi-arid regions. Hence, innovations are needed to increase the water use efficiency that is available. Deficit irrigation is believed to improve water productivity without causing severe yield reductions; which the crop is exposed to a certain level of water stress either during a particular period or throughout the whole growing season. The field experiment was conducted in Bennatsemay Woreda Weyito experimental site of Jinka Agricultural Research Center, Southern Ethiopia, during 2018 season with objective of investigating the effect of deficit irrigation on yield and water productivity of Onion under conventional furrow irrigation system. Six treatments (T1=100% ETc, T2=85% ETc, T3=70% ETc, T4=50% ETc, T5=100% ETc Is, 85% ETc Ds, 70% ETc Ms, 50% ETc Ls and T6=85% ETc Is, 70% ETc Ds, 50% ETc Ms, 0% ETc Ls) were imposed on Onion (Allium cepa L.) Bombay red variety and laid out in randomized complete block design (RCBD) with four replications. Results indicated that the different deficit irrigation levels had highly significant (p < 0.01) effect on vegetative growth, yield, yield components and water use efficiency of Onion. Onion bulb yield was reduced with increased water stress, where as water productivity was increased with stress level increased. The highest bulb yield of 21.3 t/ha were obtained from T1 which was significantly different to all other treatments while yield from T6 (12.86 t/ha) was recorded as the lowest one. Similarly, the highest IWUE (2.41 kg/m3 ) and CWUE (4.02 kg/m3 ) were obtained from T6 which was significantly superior to all other treatments. But, at T4 and T6 high yield reduction was recorded which may not be attractive for producers. On the other hand, the total bulb yield, yield components, IWUE and CWUE observed under T3 and T5 irrigation application levels had no statistically significant variation (p < 0.01). However, under T5 the relative yield reduction was greater when compared to T3. So, instead of T5, using T3 (applying 70% ETc) is advisable. Accordingly, made T5 out of the role, compared T1, T2, T3, T4 and T6, high IWUE was observed under T6 and T4 with high yield reduction penalty. From resources conservation point of view, maximum water productivity may be our attention, which could be obtained under this severe deficit irrigation. However, such consequences on yield may not be tolerable from producers view point (at T4 and T6). Therefore, it could be concluded that increased water saving and water productivity through irrigation at 70% ETc deficit irrigation level under conventional furrow irrigation system can solve the problem of water shortage and would ensure the opportunity of further irrigation development in the study area and similar agro-ecology
  • No Thumbnail Available
    Item
    ANALYSIS OF SEEPAGE AND ITS IMPACT ON EARTH DAM: CASE STUDY GEREBSEGEN EARTH DAM, TIGRAY, ETHIOPIA
    (Hawassa University, 2017-10-27) BERIHU HAILE HAGOS
    Gerebsegen dam, zoned earth type of dam with height of 46m was constructed for the purpose of irrigation and Mekelle city water supply. It is located in the Southwestern part of Mekelle city, capital city of Tigray regional state, Northern part of Ethiopia. The dominant geological formations of the site are dolerite shale and marl-limestone intercalations, characterized by cavernous, joints and karastic features which can be responsible for the excessive seepage and presents serious problems in the dam foundation, reservoir and abutments that may be so extensive as to make corrective measures impracticable. The main intention of this thesis work was to evaluate the performance of the dam related to seepage and slope stability, for which Geo Studio-2007 software (SEEP/W and SLOPE/W) was used throughout the analysis. Prior to the analysis using the model, seepage dominantly flowing through the foundation and abutments was measured using current and float method. The measured value was 0.2053 m3 /sec and the annual amount of water loss due to seepage computed was 6,474,340.80 m3 /year. By selecting three different sections of the dam during the model analysis, the average seepage flux computed at the normal pool level (NPL) and actual reservoir level (ARL) for every meter length of reservoir were 3.304E-05 m3 /sec/m and 2.252E-05 m3 /sec/m respectively. But the value computed during designing of the project where only one section of central foundation was considered, was 1.031E- 07 m3 /sec/m, which ignores the two left and right foundations which are found to be pervious and critical to the water tightness of the dam. The simulation results of SLOPE/W revealed that the downstream under steady state seepage, upstream and downstream under steady state seepage with earthquake, rapid draw down and rapid draw down with earthquake slope factor of safety are 1.805, 1.423, 1.366, 1.883 and 1.203 respectively, indicating the dam is safe against slope failure and the amount of shell materials used for the construction of the dam were excess. But the uncontrolled excessive seepage can have an adverse impact on the constructed earth dam; for which the stability of the dam against the excessive seepage needs to be assessed regularly
  • No Thumbnail Available
    Item
    ASSESSMENT OF WATER SUPPLY AND SANITATION IN RURAL AREA OF MISRAK BADWACHO WOREDA, HADIYA ZONE, SNNPR, ETHIOPIA
    (Hawassa University, 2017-10-25) TESEMA HEGANA ANEBO
    Providing access to safe water and sanitation to combat poor health is an integral part of the strategy to alleviate poverty in many countries and the sustainability of both sanitation and water schemes are basic requirement for development. The overall aim of the study is to assess water supply and sanitation and its challenges in rural area of Misrak Badawacho woreda. Questionnaires of both closed and open ended, field visit, documents review, FGD and key informants interview were used. Out of the total kebeles 10% were selected and samples were collected based on random sampling statistical technique. As found out according to the study, more than 63.53% of the community were walking more than the standard time of WHO, 64.7% of the community were unsatisfactory on water supply service, daily demand of water were only 5.97L/c/d, the actual water demand were only 1122.658m3/day but the required demand were 4701m3/day and the water coverage were only 29.85%. Unfair distribution of the schemes and HH size are also the other factors for low water consumption pd/cp. As found, the factors for sustainability of water schemes are technical factors such as absence of community participation during technology selection, absence of spare part, low quality of spare part, poor managements of both schemes and financial system. In addition to this water quality is also another factor such as pH and high concentration of manganese. All the water in the study area is corrosive due to low pH that ≥7. As found in the study area 95.3% of the community have latrine but 70.6% are unusable manner because the latrines have no proper privacy and improper for setting, 9.4% have no roof and wall, open defecation were become 35.3% in the area and only 15.3% of latrines have closed wall and roof. The other factor is cultural factors which increase open defecation. According to water quality test 80% of the water supply systems were contaminated by disease causing bacteria, there is no chlorination program of water schemes and most areas are affected by high fluoride concentration. Due to this in the study area UAP target is missed, schemes are exposed for non functionality, the clean water supply systems are not improved due to quality problem and communities are still using unimproved sanitation facilities. To overcome such problems, rehabilitation of existing system, expansion of on spot water supply systems, investigations additional water sources to increase the amount water production and minimize traveling distance. Increasing community participation, improving management system and using corrosion resistant pipes and rods increases sustainability of the water schemes. To improve water quality problems disinfection of water source, and investigation of alternative treatment method of fluoride and water sources with low fluoride are better. Working on improvement of rural sanitation facilities and using alternative means of latrine construction to minimize cultural factors in the study area.
  • No Thumbnail Available
    Item
    EVALUATION OF ALTERNATE, FIXED AND CONVENTIONAL FURROW IRRIGATION SYSTEMS ON TOMATO YIELD AND WATER USE EFFICIENCY AT HUMBO WOREDA, ETHIOPI
    (Hawassa University, 2018-12-25) TAMIRNEH KIFLE SHIKUR
    Water scarcity is one of the most important factors influencing sustainable agricultural production in arid and semi-arid regions. Insufficient water supply for irrigation was the norm rather than the exception, and irrigation management has been shifting from emphasizing production per unit area to maximizing the production per unit of water consumed, the water productivity. To cope with scarce water supplies, applying irrigation water below full crop-water requirements is an important tool to achieve the goal of reducing irrigation water use and increase water use efficiency (WUE). The objective of this research was to evaluate the three furrow irrigation systems on tomato yield and water use efficiency and identify the furrow irrigation method which allows achieving optimum tomato yield. To achieve this, experimental design was arranged in RCBD with three treatments and four replications. The irrigation treatments were Alternate Furrow Irrigation (AFI), Fixed Furrow Irrigation (FFI) and Conventional Furrow Irrigation (CFI) method. The analysis of variance indicated highly significant differences in yield and water use efficiency (P < 0.05). The result showed that conventional furrow irrigation method gave maximum fruit yield (32 ton/ha) and alternative furrow irrigation method showed highest water use efficiency (8.82 kg/m3 ), and has high marginal return rate. There for, in area where enough water available, applying water at conventional furrow irrigation system through growing season is advisable to obtain maximum tomato yield and in water scarce area applying irrigation water through alternative furrow irrigation system in four day interval is found to be economical feasible and highest water use efficiency.