Water Resource
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Item PERFORMANCE EVALUATION OF IRRIGATION SCHEME - THE CASE OF RATTE LARGE SCALE IRRIGATION SCHEME, DASENCH WOREDA, SOUTH OMO, ETHIOPIA(Hawassa University, 2016-08-18) BUBU HAILE BORDIERatte large-scale irrigation scheme is located in the in Dasench woreda, South Nation Nationality people regional state, Ethiopia, and had a service of five years. However, the performance of the irrigation scheme has not been evaluated yet. In the present study, the performance of the scheme was evaluated by estimating water delivery performance indicators, water conveyance efficiency, water conveyance losses, and satisfaction of irrigation users. The water delivery performance were evaluated by monitoring discharge at nine selected offtakes; three each at the head, middle and tail end of the scheme command area during the crop season from April to June 2022. The water conveyance efficiency of the main and secondary canals and thus the water losses in water conveyance were estimated by measuring irrigation water flow at different locations along the canals. The satisfaction of the irrigation water users from the irrigation service received was evaluated manually at the head, middle and tail end of the irrigation scheme, and for the entire irrigation scheme. Irrigation water flow in the main and secondary canals, as well as at nine tertiaries off takes was measured using float velocity method and 3-inch Parshall flume. The data were analyzed using CROPWAT 8.0, ARC GIS software, and Microsoft Excel. The analysis of internal performance indicators showed that the conveyance, application, storage, and overall irrigation efficiencies, and distribution uniformity were 57.3 %, 63.6 %, 88.17 %, 36.2 %, and 88.6% respectively while the deep percolation ratio is 35.7 %. respectively. The loss in conveyance was unavoidable unless the canal was lined or could be minimized with better canal management activities. Approximately 35.6% of beneficiaries express satisfaction with the irrigation services provided. It was generally found that the irrigation service provided to the user was insufficient, and the program's intended beneficiaries did not receive the benefits. Rearranging WAUs, improving user capacity, and optimizing water delivery scheduling. In summary, in order to optimize irrigation and water management, it is crucial to give careful consideration to converting unlined canals to lined ones and to exchanging water use management best practices from various irrigation projects that enhance the scheme's performanceItem COMPARATIVE PERFORMANCE EVALUATION OF IRRIGATION SCHEMES: A CASE STUDY OF MAI-SHAWSH AND MIDMAR SMALL SCALE IRRIGATION SCHEMES, IN MEREB SUB-BASIN, NORTH ETHIOPIA(Hawassa University, 2017-03-21) GUESH HAGOS ASRESUThis study tries to evaluate the performance of small scale irrigation schemes using comparative indicators at Maishawsh and Midmar schemes, Mereb Sub basin, North Ethiopia. This study area has poor water management practice and not evaluated before using comparative performance indicators. To address the objectives of irrigation water use efficiency and on-field irrigation management performance of this study was field measurements related to canal discharge, moisture content determination of the soils, measurement of depth of water applied to the fields using two inches parshal flume, group discussion and informant interview to establish the cost of production and the price produced. The result of this study revealed that, the conveyance efficiency for Maishawsh scheme was 98.95%, 91.03%, and 75.21%, respectively for main lined, secondary lined and tertiary unlined canals of the scheme, and for Midmar scheme, it was 76.89% which was an earthen canal. The computed application, storage, distribution and overall scheme efficiency values are 60.8, 64.2, 93.40 and 46.7% for Midmar while they are 56.8, 70, 94.2 and 42.7% for Maishawsh schemes, respectively. The comparative indicators of agricultural outputs such as land productivity measured as outputs per unit command area and outputs per unit irrigated area are 3461.58 and 3512.8 US$/ha for Midmar while 3120.91 and 3032.46 US$/ha for Maishawsh respectively. The water indicators such as output per unit irrigation supply and Output per water consumed are 0.36 and 0.61 for Midmar while they are 0.25 and 0.54 US$/m3 for Maishawsh schemes respectively. The water supply indicators measured by, relative water supply and relative irrigation supply gave 1.8 and 1.85 for Midmar while they are 2.29 and 2.37 for Maishawsh schemes respectively. This implied that the amount of water supplied was sufficient for the water demand of both schemes. The original irrigable and command area was declined by 2% from the actual irrigated area in Midmar scheme. However, the actual irrigated area was expanded by 3% and 6% from original irrigable and command area in Maishawsh scheme respectively. The financial indicators measured by gross return on investment and financial self sufficiency for Midmar are 91.5 and 69% while they are 91 and 77% for Maishawsh respectively. Based on this result, Midmar irrigation scheme was slightly better than Maishawsh, the reason might be good water management at field level and Midmar water users pay for what they have consumedItem IMPACT OF URBANIZATION ON STORM WATER RUNOFF VOLUME AND QUALITY: THE CASE OF HAWASSA CITY, SOUTHERN ETHIOPIA(Hawassa University, 2017-08-22) ASCHALEW SIDELIL SEBSIBELand use and land cover change results from various interactions between human being and environment. This study aims to identify and compare changes in land use and land cover occurred in the last 30 years in Hawassa city and its subsequent effect on runoff volume and quality. Information on land use and land cover changes that occurred from 1986 to 2016 in the study area was compared using remote sensing and geographic information system (GIS) with field verifications; Land-sat and spot satellite image were used to analyze the change. Three sets of remotely sensed Land-sat TM 1986, 2000 and 2016 were used to produce the LULC maps at different periods through a supervised classification of the satellite imageries using ERDAS IMAGINE and Arc GIS software. The Soil Conservation System (SCS) runoff volume calculation method that best fit for Ethiopia is used. Urban runoff water samples were gathered from the major runoff outfalls. The runoff sample collected manually using PVC scoop that received the entire flow and where then transferred to sampling bottles. The preparation of composite sample for one rainfall event is done by calibrating the sampling bottle with equal volume for three grab samples and preparing one event composite sample on site for that specific runoff event and sampling station. There was a significant expansion and encroachment of land use and land cover in Hawassa city between 1986 and 2016. In the study period the buildup area increased by 181.8% between 1986 and 2000. It also increased by 184.2% between 2000 and 2016. The total increment during the study period between 1986 and 2016 was about 700%. The second most changed LULC was vegetation cover that declined by 53.5% between 1986 and 2016, by 27.8% between 1986 and 2000 and finally by 37.2% between 2000 and 2016. Cultivated land was the least changed LULC. It declined by 12.2% from 1986 to 2016 but increment between 1986 and 2000 by 5.2% but decreased by 16.5% between 2000 and 2016. Bare land area also decreased by 50.8% from 1986 to 2016. The total storm water runoff depth was 35 mm and total volume was 5,833,460 m3. The storm water runoff depth indicates that 70.8% of the total rain fall changed to runoff water. During this time the contribution of the buildup area contribution was 3.8% and that of non-buildup area was 96.2% area wise. The runoff water quality laboratory results indicate that TN, TP, TSS, TDS, COD, BOD and Bacteria in the sample water were in excess of the level of permit discharge defined by the US environmental regulationItem STREAM FLOW RESPONSES TO CHANGES IN LAND USE/LAND COVER: THE CASE OF UPPER GIDABO CATCHEMENT, RIFT VALLEY LAKES BASIN, ETHIOPIA(Hawassa University, 2017-10-11) TESFAHUN TADEWOS BATEThe study analyses the land cover change between the 1996, and 2011, and the effect these changes have had on stream flow on Upper Gidabo catchment. Within Upper Gidabo catchment land use is undergoing major changes due to pressures of human activities. Changes in land use have potentially large impacts on water resources by causing more surface runoff, decreased water retention capacity, loss of wetland and drying of river. In this study, both the Soil and Water Assessment Tool (SWAT) model and Spearman`s rank correlation statistical time series analysis for measured stream flow were applied to understand the stream flow variability and land use dynamics effect on stream flow of Upper Gidabo catchment. Land use maps of 1996, and 2011 were derived from satellite images and analyzed using ERDAS Imagine 2014 software. From the land cover change analysis results it was found that there has been a substantial decline of forest lands, shrub lands, wet lands and drastic expansion of agricultural land. The SWAT modeling results showed that an increase of stream flow by 21% comparing the two land use maps (1996 versus 2011). The analysis also revealed that flow during the wet months has increased by 9.53 % while the flow during the dry season decreased by 2.36 %. Furthermore the Spearman`s rank correlation test has been applied to detect the monotonic trend existence on the mean annual, seasonal, 1- and 7- days annual minimum and maximum flows. The Spearman`s rank correlation - test demonstrates that in the case of 1-day maximum flow, no significant trend is noticeable; however, the extreme low flows indicators (e.g.1day minimum,7 day minimum) and dry seasonal flows exhibited statistically significant decreasing trends. Generally, the combined results of the SWAT model and the statistical tests revealed that land use change has caused a significant increase on mean annual stream flow and decrease dry season flows of the studied watershed during the period. The identified result is important to inform optimal water resource management and to plan and manage water resources development within the watershed in a sustainable mannerItem 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 ATSBAHAClimate 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 scenariosItem STABILITY ANALYSIS OF MIDDLE AWASH MULTIPURPOSE DAM BY INTRODUCING INCLINED CLAY CORE(Hawassa University, 2017-10-18) MELAKU SITOTAW ESHETEEarth rock fill dam with inclined core geometry is well exercised practice in most countries and this type of core arrangement has its own advantage if implemented on the right site condition, however this experience has not been exercised in our country so far. This thesis will present stability analysis of earth rock fill dam with an inclined core geometry which is proposed as an alternative design option for middle Awash dam project. The dam was designed by Ethiopian Construction Design and Supervision Works Corporation in 2016 as a rock fill dam with vertical clay core. The core geometry has been changed from vertical to inclined arrangement in this study and all analysis has been conducted and compared with the original design. The new dam geometry was fixed and checked for static loading condition and same cross section has been used for dynamic analysis. The analysis has been carried out with numerical modeling computer based software called GEO-SLOPE 2007. Based on computation, the flux through the dam has been found to be 0.0057 m3 /sec. A factory of safety of 1.72 for downstream slope during steady state, 1.464 during sudden draw down and 1.225 of downstream slope during earthquake are among the results found. The permanent deformation of the dam after earthquake, 0.803 m is also within the allowable limit. The analysis result shows that the water tightness of the dam, stability of the embankment slope and deformation of the embankment with and without earthquake has never been compromised and even the alternative design proposed in this thesis has performed in a better way for some loading conditions like downstream slope at steady state, construction stage and during dynamic loading. In addition, the revised section found to be significantly economical as compare to the original design (vertical clay core)Item Assessment of Groundwater Nitrate Level and Source of Pollution within Dire Dawa City, Dire Dawa, Eastern Ethiopia(Hawassa University, 2017-10-19) MESFIN SAHELEThis research was conducted to study the ground water nitrate level, bacterial contamination and its sources. To achieve the objective, water samples were collected from 32 water points in both rural and urban areas for testing nitrate, chloride, sulfate and fecal coliform using photometer and membrane filtration method. The research revealed that nearly 86 percent of the study area was polluted with nitrate which exceed the natural/normal 9 mg l -1 nitrate in the groundwater. The pollution was very high in the urban center and advances from the southeastern part towards the north and northwestern part of the study area. The maximum concentration of nitrate (89 mg l-1 ) was found in Addis Ketema and Ras Hotel area while minimum concentration (0.86 mg l-1 ) at Tome area which is far away from the town. Moreover, the result showed that the concentration of nitrate unevenly declines with increasing water well depth. The research also finds out that the source of nitrate was mainly attributed to infiltration of sewage from the pit latrines. Moreover, fecal coliform was found in 36 percent of the water wells covering nearly 56 percent of the study areas. The presence of fecal coliform clearly indicates the source of pollution is feces. The main determinant factor for the presence or absence of bacterial contamination is the confined aquifer nature of the water well. The correlation plot of nitrate versus chloride and sulfate indicated that there was low or no correlation in the urban center while average correlation away from the town area mainly related to the presence of excreta (single factor) that contribute for the rise of chloride. In general, the nitrate and bacterial pollution covers 86 percent and 56 percent of the study areas with the pollution source is mainly traced back to infiltration of sewage from the pit latrinesItem ASSESSMENT OF THE QUALITY OF DRINKING WATER SUPPLY, DEMAND AND SANITATION CONDITION IN RURAL AREAS OF SHEBEDINO WOREDA SIDAMA ZONE, SNNPR(Hawassa University, 2017-10-19) DANIEL SOKAMO KAMALAWater is a natural resource of fundamental importance. Ethiopia is one of the developing countries with problems of water supply and sanitation. This study was conducted in Shebedino Woreda, Sidama Zone, Southern Nations Nationalities and Peoples State. The aims of this study was to assess the quality, accessibility of drinking water supply and sanitary condition and forecast the future demand by 2026. For this study 4 rural Kebeles and 11 Water points were selected by using systematic sampling method. For household survey, 120 respondents were selected from which 70 were male house headed and 50 were women who were primary responsible in fetching water. Questionnaires were used to assess sanitary and access of drinking water to the community and personal observation was used to identify a water point and to assess sanitary condition of the water source. Also Key informant’ interviews were carried out to collect background information on hygienic behavior, accessibility of water supply and causes of water associated communicable diseases. Totally 33 samples (3 samples from each water point) were collected and tested in the laboratory to assess physico chemical and bacteriological quality of the drinking water. Data was analyzed using descriptive statistics and the result presented in frequencies, mean, standard deviation and percentages. The physico chemical and bacteriological parameters were analyzed using ANOVAs and the result was presented using tables and graphs. Based on the findings, the major problems regarding drinking water and sanitation were: low coverage (30.50%),low quantity (7.1 liters of average per capita consumption and also more than 96.67% of the people take less than 20 liters of potable water), and long water fetching time (in average 47 minutes). Likewise, sanitation situation was not so healthy and encouraging. Many factors were responsible for poor sanitation. Some of them were lack of proper disposal of garbage and toilet waste and lack of knowledge of rural people about personal hygiene and health. The survey result showed that about 51.5% of the households were disposing baby faeces and solid wastes in the open field, majorities of them (70.36%) who constructed a latrine used it now and then and also more than 50% of respondents in the study area don't use water at all for hand washing after defecating. Physicochemical quality test showed that the concentration of Turbidity is very high in Sedeka Kebele at Lamala and Shemeta sites, in Howolso Kebele at Kitawo site and in Gonowagabalo Kebele at Burama and Handisa sites. Level of Manganese also higher in Remeda Kebele at Tado site, which is much greater than WHO guideline values and not suitable for drinking purpose. According to the result of Bacteriological quality test water supply in the studied area had mean number of total coliform and fecal coliform is 8.37and 4.87respectively,which is much greater than WHO guideline values and not suitable for drinking purpose. Therefore, the major copping strategies for the challenges are water points should be protected and water disinfection techniques should be used, evaluating the existing performance, adjusting periodically revised population growth, preventive and regular maintenance program, focusing on the construction of communal latrines and integrating water supply and sanitation sectorsItem EFFECT OF MOISTURE STRESS ON YIELD AND WATER USE EFFICIENCY OF MAIZE (Zea mays L.) AT MELKASA, ETHIOPIA(Hawassa University, 2017-10-21) ROBEL ADMASU LAKEWUAt present and so in the future, irrigated agriculture will take place under water scarcity. Insufficient water supply for irrigation will be the normal rather than the expectation, and irrigation management will shift from emphasizing per unit area towards maximizing the production per unit of water consumed, the water productivity. The purpose of this study was to determine the water use efficiency of maize under moisture stress condition and to identify the critical depth of application with limited effect on yield. Field experiment was conducted at Awash Melkassa (Melkassa agricultural research center farm). The experiment was carried out in randomized complete block design with eight treatments and three replications. The treatment consists of seven moisture stress levels and one control (full irrigation, 85% ETc, 75% ETc, 65% ETc, 55% ETc, 45% ETc, 35% ETc and 25% ETc). Daily crop water requirement (ETc) was estimated by multiplying reference evapotranspiration with crop coefficient. The result reveals that the moisture stress levels set had significant impact on grain yield and crop water use efficiency. The highest grain yield was obtained from full irrigation (5524.8 Kg/ha) which was not significantly (P<0.01) different to the 85% ETc (5406.5 Kg/ha) whereas, the lowest grain yield is obtained from 25% ETc (1468.6 Kg/ha). In terms of field and water use efficiency 25% ETc gives the highest field water use efficiency and crop water use efficiency followed by 35% ETc and 85% ETc. Therefore, it can be concluded that increased water saving and associated water productivity through the use of 85% ETc, can solve the problem of water shortage which improves water use efficiency without significant reduction of yield. But if the water scarcity is high in the area 75% ETc appears to be a promising alternative for water shortage with negligible trade-off in grain yield and water use efficiencItem PERFORMANCE EVALUATION OF LAMO SMALL-SCALE IRRIGATION SCHEME IN TEMBARO WOREDA, KEMBATA TEMBARO ZONE, SNNPR(Hawassa University, 2017-10-25) TIGABU TAMIRAT OTTOREThe level of performance of irrigated farms is one of the most important issues that need to be addressed in Ethiopia where development of irrigation, in particular small-scale irrigation, is adopted as one of strategies to achieve food security. Lamo small-scale irrigation scheme operates under low level of performance due to poor water management and lack of timely maintenance of structures. The performance evaluation of Lamo small scale irrigation scheme was made by using internal performance indicators as a tool such as application efficiency, storage efficiency, distribution uniformity and deep percolation ratio. Six farmer’s plots located at head, middle and tail of the command area were selected and grown with two commonly grown vegetable crops in the command area viz, onion, and tomato. The average application efficiency, storage efficiency, distribution uniformity and deep percolation of the selected farmer's fields were found to be 48.12%, 81.90%, 79.80% and 51.88%, respectively. Based on the analysis of variance (ANOVA), the result indicated that inflow rate had significant effect (p<0.05) on different performance indicators (application efficiency, storage efficiency, distribution uniformity, and deep percolation ratio) at field level. Since farmers were using end-dyke furrow irrigation system, therefore no runoff was observed. The result of the study also showed that the irrigation water applied to farmers' fields (136mm) was much higher than the required depth to be applied per irrigation event. As a result, large amount of water was lost as deep percolation. Conveyance efficiencies of the main and secondary canals were found as 82.5% and 80.8%, respectively. Seepage losses of the main and secondary canals were found out as 16.70lit/sec/km and 14.70lit/sec/km, respectively. Operational and management, and status of physical structure of the scheme were analyzed using field observations and inventories. Moreover, poor irrigation management and operation of the scheme were identified as major problems at the study siteItem INVESTIGATING THE CAUSE OF FAILURES OF EMBANKMENT DAM (A CASE STUDY OF GRINDEHO EARTH FILL DAM, NORTHERN, ETHIOPIA)(Hawassa University, 2017-10-25)Grindeho earth fill dam located at Agulae near Wukro town, Tigray Region, North Ethiopia. Grindeho earth fill dam planned to harvest 4.2MCM of water from a catchment area of about 78.03 km2 to introduce a modern irrigation practice downstream side of the dam. The planned net irrigable area was about 400ha. However, the dam performs under capacity and does not give service yet as a result of high water loss. Therefore, the main objective of this study was to focus on the investigation of cause and type of failures of Grindeho earth fill dam. To achieve the objectives of this study, primary and secondary data has been collected from the study site, design documents, internet sources related research, references and books for emphasis the literature review, and interviewing the site engineer, hydro geologist and others. The analysis was conducted using GEO-SLOPE software to analyze the seepage flux, slope stability and stress deformation. The amount of Seepage losses through the abutments of the dam based on the design document and laboratory test data are 8.9 *10-4 m3 /sec and 1.1*10-2 m3 /sec, respectively, however the actual seepage losses of the dam based on measurement of the seepage flow at the downs stream side is 0.221 m3 /sec which is much greater than the expected as per the design, the dam has been exposed for piping failure. The stability analysis results based on design document data as well as laboratory test data indicated that the critical upstream and downstream slope of the dam are safe for the possible loading and operation cases. The stress-deformation analysis during the empty and full reservoir conditions and the maximum horizontal and vertical displacements are calculated. The maximum horizontal and vertical settlement for full reservoir conditions is found to be 0.20% and 0.94% of the dam height respectively which is within the safe limit as to deformation is considered. The impervious core material is not safe against the inside cracking and hydraulic fracturing due to the horizontal displacement, however, the dam couldn’t be affected by overtopping problem through the impact of current vertical settlementsItem ASSESSMENT OF WATER SUPPLY AND SANITATION IN RURAL AREA OF MISRAK BADWACHO WOREDA, HADIYA ZONE, SNNPR, ETHIOPIA(Hawassa University, 2017-10-25) TESEMA HEGANA ANEBOProviding 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.Item MODELING WATER RESOURCES USING WEAP MODEL FOR EFFECTIVE WATER MANAGEMENT: A CASE STUDY IN LEGEDARA RIVER CATCHMENT, SNNPR, ETHIOPIA(Hawassa University, 2017-10-27) HENOK MEKONNEN ARAGAWWater is the life blood of all living things yet its availability and management is not well understood and quantified at the catchments scale. Legedara River catchment water resources availability is not well known since the catchment is ungauged and also the water demands within the catchment is not quantified and properly allocated. This study attempted to model the water resources of Legedara river catchment in SNNPR for effective water management through scenario analysis using WEAP model.Hydro-meteorological, spatial, and water demand data were the basic inputs to the model. FAO-Rainfall-Runoff (Simplified Coefficient) method was used to estimate runoff of Legedara River catchment by transferring calibrated model parameters from gaugedWaleme River catchment. However, before transferring calibrated model parameters different procedures were done, since selection of representative catchment, modeling of gauged catchment and calibration and validation. Catchments areal rainfall and reference evapotranspiration are estimated by Thiessen Polygon method and Penman Monteithmethod respectively. Domestic, industrial and environmental water requirements were estimated using WEAP model. Current situation of water demands for the selected water users were simulated. Five different scenarios for future water demands were developed and in addition to these climate scenario was developed and evaluated. During the model setup, all demand sites were assigned equal priority. As a result of parameter derivation hydro meteorological Waleme River catchment is almost similar to Legedara River catchment. The model calibration and validation results were found satisfactory for the gauged catchment (ENS = 0.81; R2 = 0.86 and RVE = -2.64% for calibration and (ENS = 0.77; R2 = 0.81 and RVE = - 7.73% for validation). The water balance components of Legedara River catchment were estimated and mean annual values of rainfall and reference evapotranspiration found to be 1316.42mm and 1142.07mm, while the actual evapotranspiration and runoff constitutes; 538.78mm and 778.65mm respectively. The modeling result revealed that, all the selected demand sites satisfied fully in the current situation and for reference scenario, scenario one, two and four, even though the remaining river flows for the months of December, January and February were almost zero after deduction. However, the result of catchment water resources and demands showed that at the last year of scenario three (2040), there will be a 26.71MCM, i.e., 36.17%, reduction in the total annual flow of Legedara river catchment.Moreover, it was found in the catchment that it is having unmet demands in scenario three. Nonetheless, it was shown that environmental flow requirement of 14.77MCM will be fully delivered at the outlet of Legedara River catchment. Hence, no absolute scarcity of water would develop. In scenario five, the simulating value showed that, increase and decrease of current mean monthly rainfall values by 10% and 5% have an impact on increase or decrease of catchment runoff.Further researches on groundwater availability were also suggested to meet the unmet demandsItem COVERAGE AND QUALITY OF POTABLE WATER SUPPLY AND SANITATION IN RURAL AREAS OF DAMOT SORE WOREDA, WOLAITA ZONE, SOUTHERN ETHIOPIA(Hawassa University, 2017-10-27) MESERET BEKELELimited access associated with poor potable water supply, sanitation and hygiene make the community to depend on unsafe and poor water consumption and these calling for the expansion and improvement of basic water supply and sanitation services. This study was conducted in Damot Sore Woreda, Southern Ethiopia to examine coverage and quality of potable water supply and sanitation. For this study, four Kebele administrations were selected by purposive sampling technique and 83 households were randomly selected for primary data sources. Household surveys, key-informant interview and personal observations were used for primary data collection. Location map, water quality sampling point and spatial distribution of water supply schemes in the Woreda were prepared using Arc GIS 9.2 software. A total of 55 water samples were taken and examined for physico-chemical and bacteriological parameters;11from source,11 from household containers,11 from drinking cup,11 for dry and 11 for wet season. The data from the respondents were analyzed using descriptive and inferential statistical technique. Accordingly, multiple linear regression models was applied to identify factors influencing the HH water coverage, one way ANOVA were employed to see the statistical difference of the variables at 5% significant level and correlation was also used to observe associations of variables. The findings revealed that the major problems regarding drinking water were: low coverage (46.5%), low spatial distribution of water points(58.4%), low quantity(average 6.9litres) consumption per capita and almost all residents take less than 20 litres of potable water and long fetching time (average 52.75 minutes). It was observed that, HH water coverage is influenced by family size (p=0.00), functionality of the schemes (p=0.014), time required to fetch water (p=0.00) and distance to the schemes (p=0.01) was found to be significant. The result of water quality test revealed that average values for all selected physico-chemical parameters such as pH (except hand dug well at Shamba kebele), EC, Turbidity(except hand dug well, on-spot spring and hand dug well at Bolela, Anchito and Shamba kebeles, respectively), TDS, TH, Nitrate, Iron, Fluoride, Magnesium and Chloride at source, storage and point of use were found within the acceptable limit of ES and WHO. However, the mean value of Temperature and Phosphate were beyond the recommended ES and WHO standards. The laboratory result of bacteriological water quality for all sampled sites exceeded to the ES and WHO standards. The value of temperature decrease significantly from water source to HH storage (p=0.036). However, other parameters showed no significant change from source to storage. The concentration of total coliform increases significantly from supply source to point of use (p=0.024). The dry and wet season measurement showed that variation in physico-chemical and bacteriological parameters. However, statistically no significant difference observed between dry and wet season in all parameters studied. Lack of improved pit latrine, poor hand washing practice, improper handling and disposal of wastes and lack of clean storage facilities identified as the major factors responsible for poor sanitation situation, which contributes to the deterioration of drinking water quality in the Woreda. So, Woreda water supply service could not meet domestic water consumption (l/c/d) with existing capacity and gets lower. The water sources in the area are bacteriologically contaminated and therefore not suitable for domestic purposes unless treated.Item ANALYSIS OF SEEPAGE AND ITS IMPACT ON EARTH DAM: CASE STUDY GEREBSEGEN EARTH DAM, TIGRAY, ETHIOPIA(Hawassa University, 2017-10-27) BERIHU HAILE HAGOSGerebsegen 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 regularlyItem PERFORMANCE EVALUATION OF SMALL SCALE IRRIGATION SCHEME IN ADDIS-ALEM, SEHARTI SAMRE WOREDA, TIGRAY, ETHIOPIA.(Hawassa University, 2017-10-28) ABRHA FENTAW AKALUWater is scarce and expensive resource which needs to be utilized in a highly productive manner for agriculture. The main objective of this study was to evaluate the performance of the small scale irrigation scheme at Addis-Alem, Seharti Samre Woreda, Tigray Regional State. The importance of performance evaluation of small scale irrigation scheme mainly for advising irrigators on how to improve their system and management practice, intervention across different system levels, and to compute irrigation seasons and technologies The scheme has command area of 60 ha during the current study time and serving about 240 beneficiaries. To achieve the aim primary and secondary data were gathered. The internal and external performances using minimum sets of performance which includes agriculture water use economical, and physical performances. In order to compute the irrigation water use efficiency of farmers at field level, nine farmer fields were identified from the irrigation scheme in the relation to their location (head, middle and tail end water users). The internal process which include conveyance, application, storage, runoff, deep percolation ratio, distribution efficiencies, and overall irrigation efficiency were used to check the performance of the irrigation scheme. The results of the analyses indicate that the conveyance and application efficiencies were found to be 51.297 and 68.07% respectively. The runoff ratio of the scheme was nil as the furrows are block end type. Deep percolation ratio in the same order of the scheme was found to 31.93%. Storage efficiency was also estimated 47.69%. Further, irrigation uniformity of98.91% was attended. From the analysis of external indicators, the output per cropped area and output per command area were found as 4545.455 and 1363.636US$ha-1 respectively. The output per irrigation supply of the scheme was 0.663 US$ m-3 . Output per water consumed in the scheme was 0.974 US$ m-3 . The water use performance of the scheme was computed, water supply and relative irrigation supply were found as 7.362.The irrigation ratio of the scheme was found to be 0.30 which means about 70% of the command area is not under irrigation during the study period. In general,, the performance of Addis-Alem irrigation scheme is low . But there is still a room for improving the performance of the scheme by resizing the main canal as well as the secondary and tertiary canals which were not adequately carrying the required irrigation waterItem 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 TAREKEGNAndasa 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 scenarioItem COMPARISON OF MUSLE, EPM AND PSIAC SEDIMENT ESTIMATION MODELS: CASE STUDY GEREB-SEGEN DAM WATERSHED, TIGRAY, ETHIOPIA(Hawassa University, 2017-12-22) SOLOMON HAILU GEBREEGZIABHERSedimentation of the dam reservoir is a series problem in Ethiopia. It also a major problem in many developing countries causing significant loss of water storage ,loss of agricultural productivities, loss of electrical supply and ecological changes. The MUSLE, EPM, and PSIAC models are tested for the prediction of sediment yield at Gereb-segen watershed, Tigray, Ethiopia. Poor land use practices and improper management systems have played a significant role in causing high soil erosion rates, sediment transport and loss of agricultural nutrients. The main objective of this study is comparison of sediment yield of the Gereb_segen dam reservoir, using the MUSLE, EPM and PSIAC models with the observed data and selection of appropriate model for the area. The research integrates the three models with Geographic information system (GIS), Remote sensing and Digital elevation model. Rain fall data, soil data , Geological data , Temperature, land use and land cover, crop management and conservation practices, infiltration rate of soil at filed level were used as input data sets to generate the three model factor values. As a result, MUSLE estimates that sediment yield of the study area to the range between 3.89 & 26.45 ton/ha/yr where as EPM estimates the sediment yield in the range of 84.20 to 344.09 ton/ha/yr and PSIAC also estimate 0.16 to 8.90 ton/ha/yr. As they were, compared the three models used to estimate sediment yield of the target area with the measured data which studied by Haregeweyni et al.(2008) sediment yield of 11.82 ton/ha/yr, the MUSLE similar with 82.06% and the PSIAC model similar with 12.35% while the EPM model it is more differ from the measured data. Using the MUSLE model the Gereb-segen watershed sited 0.28% under low, 4.29% moderate, 48.64% high and 46.79% very sedimentation classes.Item P E V LA UA IT ON OF G NILO A MS ALL S C ELA GIRRI A S OIT CHE EM R( AYA OK B )O , HTE I IPO A(Hawassa University, 2017-12-27) S EL W N SAGE HT uts dy saw taitini ed ot sessa s na d lave au et eht p fre o namr ce of aniloG llams sc ela noitagirri mehcs e su gni lanretni ep r amrof n ec ni d srotaci ( vnoc eyan ec ffe i neic cy, noitacilppa eiciffe ncy, rots a eg ef cif i ne cy dna noitubirtsid u imrofin ty) os sa ot reco dnemm etairporppa serusaem ot orpmi ve eht mehcs e nam a tnemeg dna ep r namrof ce. oT u tredn eka siht uts dy amirp ry d ata ( csid harge stnemerusaem ni eht ac n ,sla nemerusaem t fo ped th fo retaw deilppa t o eht remraf s’ ,dleif dleif ,snoitavresbo iweivretni ng neb e aicif ry f mra e ,sr a dn noitanimreted of erutsiom stnetnoc fo the lios erofeb dna tfa re irri g ,noita itanimreted on fo lios phy acis l seitreporp ) dna se adnoc ry atad w ere lloc e .detc As ot eht retaw eviled ry s ,ecivre eht cs h me e saw sed ig den ot eviled r noitagirri retaw ot laudividni sdleif desab no lanoitroporp wolf s uorht g tuoh the rri i noitag nosaes , tub a lautc w eta r eviled ry ivres ce to rri i srotag aw s wonknu n etad na d .emulov It was dnuof taht ht e vnoc eya cn e e eiciff n seic of iam n anac l eno dna owt erew %3.37 dna 5.97 7% evitcepser ly. ehT oc nveyance ciffe i seicne fo eht adnoces ry c lana s eno ot is x erew ,%75 ,%97 ,%08 ,%8.87 57. %4 dna %27 r vitcepse le y. ehT oitacilppa n eiciffe ncy tluser no erht e stops in ’sremraf dleif detacol ta ,daeh elddim dna liat sehcaer fo eht dnammoc erew dnuof ot eb ,%62.84 %15.86 and %56.57 evitcepser ly. sihT swohs taht ht e vnoc eyan ec ef neicif cy of eht niam dna adnoces ry c slana eno dna evif dna eht daeh tolp pa noitacilp ciffe i ne cy we er dnuof ot eb woleb ht e ex detcep .level desaB on eht tnemssessa o f emraf r s’ pe noitpecr ba o tu eht frep o namr ce fo eht rri ig noita ehcs me ti si dnuof taht la l stnednopser oc n demrif th ta uoht gh eht hsilbatse m tne fo eht s mehc e si ev ry tnatropmi rof eht m ot eruces doof les f- fus f neici cy, ht ey fe le taht ti si on t nimrofrep g w .lle ehT dlohesuoh stnednopser eveileb am j ro smelborp taht ekam eht emehcs neiciffeni t erew anetniam nc e melborp ,)%1.72( retaw tfeht ro irohtuanu z de lanac ihcaerb ng ni eht emehcs ,)%8.02( taw re egatrohs %7.81( ) na d wa ret ilitu z noita tcilfnoc (1 .)%5.2 G ene r la ly ht e vo e llar ep r amrof nce o f eht mehcs e si etar d sa po ro . It etacidni s taht rri iga srot deen te lacinhc ppus o tr dna wollof up in era a fo no - mraf w reta m na ag ,tneme nac la m ,ecnanetnia dna lanoitutitsni troppus ni smret o f nitatilicaf g s e secivr dna a ram ot ssecc k ot sa os te f ts rehtra reng .Item ANALYTICAL EVALUATION OF NATURALLY EXISTING SLIGHTLY WEATHERED ROCK AGAINST BLASTED ROCK AS EMBANKMENT MATERIAL (A CASE STUDY OF RIBB DAM(Hawassa University, 2017-12-27) SELAMAWIT TESFAYE G/HANAFundamentally, a good embankment dam design should not only refer to the one which is structurally stable and safe. However, it should also comprise of the actual site condition like use of easily available materials for construction purpose. Utilizing of locally available material for embankment dam will have economic advantages avoids construction difficulty and shortens construction periods. Ribb rock fill dam was designed and constructed with a significant volume of rock material produced by blasting and further degrading process to satisfy the gradation requirements. However, the site was rich with a slightly weather fine rock fill material which can easily be produced and stock pilled with normal production process of using machineries. Hence, this thesis presents the overall stability analysis for revised Ribb dam replacing the rock fill material with slightly weathered rock to show the effect of shallow geotechnical investigation works on dam projects. Numerical modeling software called GEO-Studio 2007 has been used for the analysis. Based on the analysis carried out for different loading conditions, the revised section satisfies all the requirements suggested by standards and improved factor of safeties of 1.801 for steady state seepage, 1.489 for sudden draw down and 1.396for steady state with earthquake has been found. Besides the newly revised design has been found economical since saves 497,536.439.19ETB, less difficult for construction and considerably shortens construction period.