Water Resource

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A Thesis Submitted to Institute of Technology, School of Biosystems and Environmental
(Hawassa University, 2018-10-21) GULILAT GEBRECHRISTOS EARGENA
The development of balanced plan for water resource utilization requires assessment of the water resources in terms of quality, quantity, spatial distribution and the land use land cover condition of the entire catchment area. This thesis work is aimed to characterize different aquifer systems and their hydrochemistry in Tikur Wuha River catchment which is located in South part of Ethiopia particularly in Sidama Zone. The catchment area of Tikur wuha River 625 km2. The area is located in central part of MER and generally characterized by two topographic features. which is the high land near the rift escarpment and the rift floor. The study area is covered by Recent lacustrine and alluvial deposits, scoria cones, rhyolitic lava flows and associated ignimbrites, tuffs and volcanic ash. The escarpment and the mountains of the eastern margin of the catchment are made up of Nazeret series, which is composed of ignimbrite, unwelded tuff, ash flow, rhyolitic flow, domes and trachyte. The low laying area which is the rift floor is covered with lacustrine and alluvial deposits. The hydrogeological classification is done using qualitative and quantitative approaches based on the hydrogeological characteristics of lithological unit and different data collected from different organization, based on this the study area is classified in to the following aquifer aquiclude system. Extensive and highly productive porous aquifer (T=110-2000 m2/day, K=5-400 m/day and Q= 17-70 l/s). Highly to moderately productive mixed porous and fissured aquifers (T=500-2700 m2/day, K=15-560 m/day and Q= 10-30 l/s). Extensive moderately productive fissured aquifer (T=10-110 m2/day, K=0.5-5 m/day and Q= 5-10 l/s). Extensive low to moderately productive mixed porous and fissured aquifer (T=10-55 m2/day, K=0.1-1 m/day and Q= 2.5-5 l/s). Low potential aquifers and aquicludes also cover some parts of the study area. Aquachem software has been employed to identify the different water types. From the analysis of hydrogeochemical data different water types are identified of which the majority of the cold springs, dug wells and boreholes from the highlands and escarpments are Ca-Mg-HCO3 type and Ca-Na-HCO3 type. The majority of waters from the rift floor boreholes and shallow wells; sodium is the dominant cation and the dominant anion is bicarbonate. These ground waters are Na–Ca-HCO3 and Na- HCO3 type.
A WATER SUPPLY SYSTEM STUDY AND ASSOCIATEDGAPS ON SANITATION OF THE DAYE TOWN, SIDAMA REGIONAL STATE, ETHIOPIA
(Hawassa University, 2021-07-18) ABERRA ELEFEW ASAMINEW
Safe and adequate delivery of water to a consumption node is an essential function of a water distribution network. Daye Town has experienced frequent and regular disruption of water because of hydraulic problems related to pressure and velocity during high consumption period and at night-time. The main aim of this study was to model the existing water distribution system for steady-state and evaluate hydraulic performance of the system and sanitation condition of the town. For conducting this study, both primary and secondary data were collected and tools such as WaterGEMS and SPSSwere used. Questionnaire was used for the sanitation assessment for the selected sample households. Pressure gauge was used and the pressure on the selected points on the water supply system measured and then validated with the result from hydraulic modeling analysis. The existing water sources studied, and the population of the town analyzed for the present and the forecasted, 20 years. Accordingly, the total average per capita consumption of the Town in the year 2022was 9.21 l/c/d which showed lower performance compared to 50 l/c/d which is set by GTP-II of the country for category 4 town and 34,714m 3 /year (25.03%) of water is considered to be non-revenue (NRW) and the apparent losses and real losses of the town was 0.9% and 26.44% respectively. There is high gap between demand and supply in the town because the current (2022) and the future (2041) maximum day water demand of the town was 1741.04m 3 /day and 4,581.81 m 3 /day respectively and the current (2022) water production of the town was only 511.2 m 3 /day which only satisfies 44% of the current demand (2022) and 17% of the future demand in year 2041. Therefore, securing additional water supplies becomes an essential issue to meet the current and future water demand of the town. The simulated result showed that 41.35% for pressure value (<10m) and 58.65% for pressure value with recommended value (11-70m) base xii consumption and the velocity of pipe flow showed that 51.3% (<0.6m/s) and 48.7% the range of (0.6-2m/s). The performance of the model was evaluated using model evaluation statistics. The value of the coefficient of determination (R2 ) for pressure calibration was 0.96. Moreover, potential causes of water losses in the town water supply system were assessed, water losses reduction strategies are designed, and the system pressure and velocity are adjusted. Finally, sanitation associated gapsmainly the latrine in household and selected institutions and excreta disposal and transportation was assessed. Percent of households with access to sanitation facility and percent of households with year-round access to improved water system for sanitation was27.52% and 15.5% respectively
ANALYSIS OF HYDRUALIC PERFOMANCE OF ALETA WONDO TOWN WATER SUPPLY DISTRIBUTION SYSTEM
(Hawassa University, 2021-10-25) TEKA FETOSA JILO
In many of the developing countries, the hydraulic and physical performance of water distribution network is inadequate to meet consumers’ demands that encounter significant losses in the system. Aleta-Wondo has been experiencing frequent and regular disruption of water supplies for days to a week. This study was conducted in Aleta-Wondo Town to analyze the existing water supply distribution system of the Town. Both primary and secondary data sources were used in this study. Primary data were collected though face-to-face interview with Aleta Wondo Water Supply Office experts, field observation. For secondary data collection, document review was used to collect valuable information. To analyze the data which is collected from different sources, both qualitative and quantitative methods was used. Software applications tools called Origin8 WaterGEMSv8i and excel were used to analyze the data obtained from different source. The analysis shows that the current total domestic water demand in town was higher than supply, the water supply coverage was evaluated based level of connection per family and average per capita domestic water consumption was 14.11 l/c/day. Hence, this result indicates there is a gap between demand and supply in the year 2020. The average water loss in Town was 31%, showing that needs a matter of concern. None of the junctions had pressure bigger than 70 m. 65.21% of the junction water column recorded a pressure less than 15m water column due to high elevation. 34.79% of the Town has pressure within the optimum range of 15- 70 m water column and the highest or lowest velocity recorded was zero during steady state analysis. Velocity in some pipe parts was below 0.6 m/s during steady period simulation. Generally the result of the analysis shows that the overall hydraulic performance of the water distribution system of the Town was poor, which is reflected by low water production rate, low water consumption, and high level of non-revenue water, low service coverage, not pressure in permissible range. Therefore, it is significant to rehabilitate and improve the water distribution system capacities, establishing pressure zone, increase pumping rate and drilling additional borehole. In addition provision of more attention to water losses reduction policies and strategies are vital for remedial measures
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
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/HANA
Fundamentally, 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.
ASSESING THE IMPACT OF LAND USE / LAND COVER CHANGE ON STREAM FLOW (THE CASE OF UPPER AWASH RIVER BASIN, ETHIOPIA
(Hawassa Unversity, 2020-10-20) WORKU NIGUSSIE YOSEF
The population growth for the last 33 years caused changes in land cover of the upper Awash River basin of Ethiopia. The effect of the land cover changes has impact on the stream flow of the watershed by altering the magnitude of surface runoff and ground water flow. This study aimed at investigating the impacts of the land use/land cover change (LU/LCC) on the stream flow of the upper Awash River basin. Both meteorological and hydrological dataset was gathered and analyzed for a period of 1986 to 2018. Land use change detection was done using remote sensing techniques and the maps were processed using ERDAS Imagine 2014 in conjunction with ArcGIS10.1 software. The land use land cover maps were classified using the Maximum Likelihood Algorithm of Supervised Classification. The accuracy of the classified maps was assessed using Confusion Metrics. The result of this analysis showed that the cultivated land, water body and settlement area has expanded but forest and, grass lands has shown a substantial decline during the study period of 1986-2018. The Soil and Water Assessment Tool (SWAT) model was used to simulate the stream flow under different LU maps. The model was calibrated during a periods of (1986 to 1991), (1996 to 2001), (2006 to 2011) and validated during a periods of (1992 to 1995), (2002 to 2005), (2012 to 2015) for land use/land caver of 1986, 2002 and 2018 respectively. The results of sensitivity analysis show that fifteen flow parameters were identified to be sensitive for the stream flow. Calibration and validation on monthly stream flow is performed by dividing stream flow from (1986_1995) first class for1986 land use and land cover, (1996_2005) second class, for 2002 land use and land cover and (2006_2015) 3rd class for 2018 land use and land cover respectively. For 1986 LULC class of Calibration period, Nash-Sutcliffe simulation efficiency (ENS) of 0.78 and coefficient of determination (R2 ) of 0.84 and validation ENS value of 0.60 and R2 of 0.76 respectively. For 2002 LULC class of Calibration period, Nash-Sutcliffe simulation efficiency (ENS) of 0.81 and coefficient of determination (R2 ) of 0.86 and validation with the ENS value of 0.62 and R 2 of 0.82 respectively. For the 2018 LULC class of Calibration period, Nash-Sutcliffe simulation efficiency (ENS) of 0.85 and coefficient of determination (R2 ) of 0.89 and validation with the ENS value of 0.64 and R 2 of 0.84 respectively. The trend analysis indicated that flow during the wet months has increased by 34.4% and 10.7% between 1986 to 2002, and 2002 to 2018 respectively. While the flow during the dry months decreased by 4.6% and 6.9% between 1986 to 2002, and 2002 to 2018 respectively. Generally, the analysis indicated that flow during the wet months has increased, while the flow during the dry months decreased. The SURQ increased, while GWQ decreased from 1986 to 2018 due to the increment of cultivated land and expansion of urbanization. The model results showed that the stream flow characteristics changed due to the land cover changes during the study period
ASSESMENT OF CHALLENGES OF SUSTAINABLE RURAL WATER SUPPLY: THE CASE OF GAMBELLA ZURIA WOREDA, GAMBELLA REGION, ETHIOPIA
(Hawassa University, 2018-10-20) SELESHI MANAYE DERSEH
Sustainability of water supplies is a key challenge both in terms of water resources and service delivery. Furthermore, it is the key to identify what enables a water scheme to remain operational over a long period of time. Consequently, the objective of this study was to identify the main challenges of sustainable rural water supply systems by evaluating and comparing functional and non-functional systems. The study was carried out in Gambella Zuria Woreda located in West of Gambella town, Gambella Region, Ethiopia. Both primary and secondary data sources were carefully examined. Both quantitative and qualitative research methodologies were used to analyze the data. Score matrix, questionnaire, and focus group discussions were among the selected methods. Water quality testing was done to examine suitability of water sources. The result obtained from tested parameters indicated that except the pH and F values, all parameters values are out of the World health organizations (WHO) standards for drinking water. The parameter values were found to be in the range of pH (6.9- 8.0), Turbidity (2.21-15 NTU), EC (495 – 1123.00 μS/cm), TDS (230-1300 mg/L), TH (183-913.0 mg/L), Fe2+ (0.06-0.67 mg/L), Fluoride (0.11- 1.21mg/l), Ca2+ (5.3-78.00 mg/L) and Mg2+ (13-98.30 mg/L). Additionally, the overall quality of the groundwater low in the sampled sites of the study area and this situation needs urgent and strategic solutions. From this study all the water schemes non-sustainability problems are low water quality, lack of proper operation and maintenance, weak management which resulted in the Woreda’s inability to achieve full coverage of the rural population with safe water services. On the other hand, the finding of this research show that, 45% of functional water supply schemes and 23% of nonfunctional water supply schemes respondents said that the collected water tariff cover the operation and maintenance cost of water supply schemes, and 35% of functional water supply schemes and 86% of nonfunctional water supply schemes respondents responded have problem of ability to pay water tariff. Therefore, regular maintenance of water schemes, awareness creation of the water users, training of water point committees and follow up to the community by the water Bureau of the Wereda can be a better solution to solve the problem before it gets worse
ASSESSEMENT OF COVERAGE AND QUALITY OF POTABLE WATER AND SANITATION IN RURAL AREAS OF KUCHA WOREDA, GAMO ZONE, SOUTHERN ETHIOPIA
(Hawassa University, 2024-10-22) MEKURIA MUNDARE MULATE
Safe water supply and sanitation services are basic requirements for a society. Limited access associated with poor water supply, sanitation and hygiene make the community to depend on unsafe and improvement of basic water supply and sanitation services to give proper and timely response. Thus, this study was conducted to evaluate coverage and quality of potable water supply and sanitation services and forecast the future demand by 2035 for Kucha Woreda. Five Kebele administrations were selected by purposive sampling technique. Totally 110 households (HHs) were selected as a sample population for primary data sources are then distributed to each Kebeles proportionally by using purposive sampling technique. The data sources for the study were both primary and secondary. For secondary data collection document review was used as a tool to collect valuable information. Household surveys, personal observations and key-informants interview were used for primary data collection. The data from households were analyzed using descriptive statistical techniques and explanation building. The inferential statistics one way ANOVA and were descriptive statistical employed to see the statistical significances and associations of the variables respectively. The major finding showed that there are low coverage (21.9%), inadequate spatial distribution of water points (58.4%), low per capita consumption (an average of 7.36 liters), with almost all residents consuming less than 25 liters of safe water, and waiting water-fetching times (an average of 52. 5 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 more than 51.4% of the households were disposing baby faces and solid wastes in the open field, majorities of them (26.5.%) using water only, water use and ash 14.1% of respondents in the study area don't use water at all for hand washing after defecating. The result of water quality test of the study area obtained overall water quality indicates that most parameters are within standard except parameters like Temperature, Iron and phosphate that do not fulfill the WHO and Ethiopian drinking water standards. Bacteriological results show that the presence pathogens i.e. total coliform four water sample sites contaminated exceeding the WHO and Ethiopian standards which do not allow any fecal or total colonies in drinking water
ASSESSEMENT OF URBAN WATER SUPPLY ADEQUACY AND EVALUATION OF HYDRAULIC INTEGRITY (THE CASE IN SHONE TOWN, HADIYA ZONE SNNPR STATE
(Hawassa University, 2023-10-24) WAJANA SORSA BARATA
The importance of water to living things cannot be overemphasized. Providing adequate and sustainable water supply to the rapidly growing population in expanding and developing towns of Ethiopia is getting a challenge from time to time. The main objective of this study focuses on assessing water supply adequacy and evaluating hydraulic integrity through: analysis of water supply coverage, assessing water supply source, assessing system water loss, analysis of current & future water demands and evaluating hydraulic integrity of existing water distribution system by using WaterGEMS software simulation in Shone town, which is located at Hadiya zone, SNNP Regional State of Ethiopia. Both primary and secondary data were collected and used during study and analysis. The primary data collected includes existing pipes network GPS data and water pressure gauge readings from customer faucets. The secondary data collected includes existing water supply system information, type and number of existing mode of service, water production & consumption data, pump & BH data and financial transactions from customer billings. The methods employed during the study include, collecting and analyzing both primary and secondary data & tools used were GPS, Water GEMS Connect edition, ArcGIS 10.3, AutoCAD and statistical analysis. Based on this pipe networks were created, model developed and water GEMS simulation was conducted to test and analyze the hydraulic integrity of existing water distribution system. Accordingly, the total calculated average per capita domestic water consumption of the town for the year 2023 was 15.76 l/capita/day and the amount of water lost from system as non-revenue (NRW) was 106,963.16m3 (36%).The current year 2023 and future 2042 maximum day water demand of the town was 3899.27m3/d and 11615.11m3/d respectively but the amount of water supply from the source to the system is only 1267.20m3/d. After modeling & simulation in peak hours, the distribution system analysis showed that 25.58% of the junctions have above the maximum and 51.16% of the junctions have below the minimum operating pressure and 1.5% of the pipes have above the maximum and 43.28% of the pipes have below the minimum permissible velocity ranges respectively. Therefore, the calculated average per capita domestic water consumption only satisfies 26.27% compared to 60 l/c/d set by GTP-II of the country for category 3 urban town like Shone and the town is under sever conditions in water loss balance as compared to GTP-II target to minimize (<20%), moreover, the amount of water supplying to the system from source can only satisfies 32.51% for current and 10.91% for future demands in 2042. So this points out that availing supplemental water sources becomes the key gap to meet the current and future water demand of the town. The hydraulic analysis result of the system indicates, presence of various shortcomings to existing water supply system in terms of hydraulic integrity, these are oversized and undersized pipes, irregular flow velocity and low pressure (-22.25m H2O) and extremely high pressure values (108.96m H2O), low source water supply and improper pipe size. Moreover, performance of the model was evaluated using statistical evaluating tool. As the result, the value of coefficient of determination (R-value) in pressure calibration calculated was 0.998. Therefore, findings of this research is promised to help the stakeholders to intervene and take timely actions by upgrading the existing water supply system to meet the current and future water demand of the town.
ASSESSEMENT OF URBAN WATER SUPPLY ADEQUACY AND EVALUATION OF HYDRAULIC INTEGRITY (THE CASE IN SHONE TOWN, HADIYA ZONE SNNPR STATE
(Hawassa University, 2023-10-21) WAJANA SORSA BARATA
importance of water to living things cannot be overemphasized. Providing adequate and sustainable water supply to the rapidly growing population in expanding and developing towns of Ethiopia is getting a challenge from time to time. The main objective of this study focuses on assessing water supply adequacy and evaluating hydraulic integrity through: analysis of water supply coverage, assessing water supply source, assessing system water loss, analysis of current & future water demands and evaluating hydraulic integrity of existing water distribution system by using WaterGEMS software simulation in Shone town, which is located at Hadiya zone, SNNP Regional State of Ethiopia. Both primary and secondary data were collected and used during study and analysis. The primary data collected includes existing pipes network GPS data and water pressure gauge readings from customer faucets. The secondary data collected includes existing water supply system information, type and number of existing mode of service, water production & consumption data, pump & BH data and financial transactions from customer billings. The methods employed during the study include, collecting and analyzing both primary and secondary data & tools used were GPS, Water GEMS Connect edition, ArcGIS 10.3, AutoCAD and statistical analysis. Based on this pipe networks were created, model developed and water GEMS simulation was conducted to test and analyze the hydraulic integrity of existing water distribution system. Accordingly, the total calculated average per capita domestic water consumption of the town for the year 2023 was 15.76 l/capita/day and the amount of water lost from system as non-revenue (NRW) was 106,963.16m3 (36%).The current year 2023 and future 2042 maximum day water demand of the town was 3899.27m3/d and 11615.11m3/d respectively but the amount of water supply from the source to the system is only 1267.20m3/d. After modeling & simulation in peak hours, the distribution system analysis showed that 25.58% of the junctions have above the maximum and 51.16% of the junctions have below the minimum operating pressure and 1.5% of the pipes have above the maximum and 43.28% of the pipes have below the minimum permissible velocity ranges respectively. Therefore, the calculated average per capita domestic water consumption only satisfies 26.27% compared to 60 l/c/d set by GTP-II of the country for category 3 urban town like Shone and the town is under sever conditions in water loss balance as compared to GTP-II target to minimize (<20%), moreover, the amount of water supplying to the system from source can only satisfies 32.51% for current and 10.91% for future demands in 2042. So this points out that availing supplemental water sources becomes the key gap to meet the current and future water demand of the town. The hydraulic analysis result of the system indicates, presence of various shortcomings to existing water supply system in terms of hydraulic integrity, these are oversized and undersized pipes, irregular flow velocity and low pressure (-22.25m H2O) and extremely high pressure values (108.96m H2O), low source water supply and improper pipe size. Moreover, performance of the model was evaluated using statistical evaluating tool. As the result, the value of coefficient of determination (R-value) in pressure calibration calculated was 0.998. Therefore, findings of this research is promised to help the stakeholders to intervene and take timely actions by upgrading the existing water supply system to meet the current and future water demand of the town
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
ASSESSING THE EFFECT OF LAND USE LAND COVER CHANGE ON STREAM FLOW AND SEDIMENT YIELD: THE CASE OF ROBIGUMERO WATERSHED, UPPER BLUE NILE BASIN, ETHIOPIA
(Hawassa University, 2024-07-26) KASAHUN TADESSE MARE
Land use and land cover change significantly affected global water yield and sediment yield. The population within the Robigumero watershed experiences periodic increases that are attributable to changes in land use and land cover patterns occurring over both a spatial and temporal scale. Therefore, this study mainly focused on assessing LULC change and analyzing its impact on stream flow and sediment yield in the Robigumero watershed. For this study, spatial and hydro-meteorological data were used as model input. ERDAS Image 2015 was used to assess land cover classification and accuracy. SWAT model was used to simulate stream flow and sediment yield in monthly time steps. The model predicted stream flow with R2 values of 0.89 and 0.77, NSE values of 0.87 and 0.76, and PBIAS values of -2.3 and -5.1 during calibration and validation periods, respectively. Similarly, the model predicted sediment yield with R2 values of 0.80 and 0.75, NSE values of 0.80 and 0.74, and PBIAS values of -7.1 and 0..9 during the calibration and validation periods, respectively. During the study period from 1994 to 2021, the Robigumero watershed experienced substantial LULC change, with agricultural land and built-up area increasing by 18.6% and 160.8%, respectively, while forest, grassland, and shrubland cover decreased by 12.7%, 10.4%, and 40%, respectively. The calibrated model predicted results showed that on the watershed outlet point, mean annual stream flow increased by 4.64 m3 /s, and mean monthly stream flow increased by 0.86 m3 /s during the wet season and decreased by 0.14 m3 /s during the dry season from 1994 to 2021. Similarly, annual sediment yield increased by 5.5 t ha- 1 .yr-1 , with seasonal yields increasing by 4.84 t ha-1 .yr-1 during the wet season and 0.49 t ha- 1 .yr-1 during the dry season. Spatially, nine subbasins (43.3%) of the catchment revealed sediment yield-critical areas; from these, 24.02 t ha-1 yr-1 of sediment was generated. Implementing terracing, filter strips, and contouring in the critical subbasins demonstrated sediment yield reductions of 71.1%, 46.3%, and 51.9%, respectively. The findings of this study indicate that annual and wet season stream flow and sediment yield increased, while dry season stream flow was reduced. The change in stream flow and sediment yield is a direct result of the significant change in land use and land cover in the watershed. This suggests soil and water resource development in the catchment needs urgent regulation by the LULC and should be given priority to sediment reduction measures
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
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
ASSESSING THE IMPACT OF LANDUSE/LANDCOVER CHANGE ON THE HYDROLOGICAL RESPONSE OF KOLA RIVER WATERSHED, SIDAMA REGION, ETHIOPIA
(Hawassa University, 2021-10-23) NIGUSU MULETA ETANA
Landuse/land cover change is one of the major factors that affect the hydrological response of watersheds. Hence studying the impacts of past and future landuse/land cover changes on the hydrology of Watershed is very important for proper watershed management. This study investigated the past and potential future land cover changes and their impact on the hydrological response of the Kola River Watershed by using the Soil Water Assessment Tool (SWAT).To detect and analyze the change that had taken place in the study area, satellite images were downloaded for 1988, 1998, 2008, and 2018 years and processed using ERDAS Imagine 2014. Then by using the supervised image classification technique, the satellite images were classified to agriculture, agroforestry, built up pasture, land, and forest landuse the land cover types. Then accuracy assessment was done, and overall accuracy of 87.83%, 88.41%, 89.15%, and 91.76%, was achieved for the classified images of 1988, 1998, 2008, and 2018 respectively. The changes of landuse/land cover of the study area from 1988 to2018 indicated that Pastureland, Forest, and Agroforestry decreased by 69.55%, 40.86%, and 15.77%, while Agriculture, and Built-up, increased by 24.67%, and 23.9%, respectively. The future LULC of 2048 was projected by IDRISI (CA-Markov method) and the result indicated a continuous increase of Agriculture and Built-up areas as the other landuse land cover such as forest, pastureland and Agroforestry decreased. Model sensitivity analysis was made to choose the most sensitive parameters. Then, R2 and ENS achieved 0.87, 0.77 during calibration and 0.85, 0.74 for validation respectively. The model performance evaluation indicated that SWAT can be used for modeling the impact of historical and projected LULCC on the hydrological response of the study Watershed. As the investigation of 1988 to2018 shows, due to LULCC, the seasonal flow increased by 25.71%, 23.73%, and 19.96%in the first and, second rainy seasons, and short rainy season, while it decreased by 22.21% in the dry season respectively. The annual surface runoff and water yield increased and by 22.21%, and 3%, whereas evapotranspiration and lateral flow, decreased by, 6.21%, and 14.61% respectively. The future LULCC prediction of 2048 showed thatseasonal flow increased by 29.03%, and 28.08%, 14.6% in the first and second rainy season, and short rainy season and decreased by 19.3 in dry seasons. Generally, the investigation of hydrological response to LULCC by taking other data constantly at different predefined study years indicates LULCC has significant impacts on the hydrological response of the study watershed. Therefore to overcome the impact of LULCC, local and national policymakers should be invited to prepare and apply scientific and appropriate watershed planning and management, strategies in the Kola River Watershed
ASSESSING THE IMPACT OF LU/LC CHANGE ON HYDROLOGICAL RESPONSE BY USING SWAT MODEL: A CASE STUDY AT DEDABA WATERSHED, ETHIOPIA.
(Hawassa University, 2021-04-26) IBSA DIBO DEKO
Water is a precious and finite resource and must be managed in sustainable way to meet human as well as environmental needs. Land use/land cover change has an impact for alteration of watershed hydrology. The watershed is undergoing land use change due to intensive cultivation andurbanization as a result of population growth which has an impact on hydrologicresponse of the watershed. This study quantified watershed runoff volume using SWAT modeland assessed the effect of land use/land cover change on the stream flow. In this study, the impact of LU/LCchange was carried out by using the Soil Water Assessment Tool (SWAT2012) model, which was integrated with GIS10.3 software. GIS and ERDAS IMAGINE2014 were used to generate LU/LCmaps from Landsat TM, TM, and OLI acquired in the years 1990, 2001 and 2018 respectively. The land cover maps were generated using the maximum likelihood algorithm of supervised classification. The classified maps were assessed using confusion metrics. The results of the analysis showed that the Agricultural land has expanded during the study period of 1990-2018. During the study period, forest land, and shrub and grassland decreased by 19.5% and 15.61% respectively while Agricultural land and Built-up area increased by 33..63% and 1.48% respectively. Using three land cover maps, three SWAT model setup were run to evaluate the impacts of LU/LC changes on the streamflow of the study watershed. The performance of the SWAT model was evaluated through sensitivity analysis, calibrationand validation by using SWAT-CUP. The Coefficients of determination and Nash–Sutcliffe were used to evaluate the model and it resulted in 0.87 and 0.73 for calibration and 0.82 and 0.68 for validation respectively. During the study periods, the simulation result indicated that streamflow increased in the wet season and short rainy season streamflow by 9.64% and 3.05% respectively, while decreasing by 5.6% in the dry season. The Surface Flow (SURQ) increased by 12.58% while Groundwater Flow (GW_Q) decreased by 14.83% due to the increment of Agricultural land. The study resultsshowed change in flow with change in land use/landcover, so it needs landuse planning and sustainable water resource management
ASSESSING THE IMPACTS OF CLIMATE CHANGE ON STREAMFLOW UNDER CMIP6 CLIMATE PROJECTION IN THE UPPER OMO GIBE RIVER BASIN, ETHIOPIA
(Hawassa University, 2023-03-25) LEMLEM GETNET MOLA
Climate Change is projected to have an impact on future streamflow in various watersheds. This study examined the impacts of climate change on streamflow in the Upper Omo River Basin using a Soil and Water Analysis Tool (SWAT). Projected climate variables (precipitation and temperature) ensemble of 5 Global Circulation Models (GCMs) were obtained from the World Climate Research Programme (WCRP), downscaled by the SDSM4.2 model and applied under the Shared Socioeconomic concentration pathways (SSP2-4.5) and (SSP5-8.5) scenarios. The downscaled SSPs data cannot be directly used to the hydrological model (SWAT) to simulate flow so, Distribution Mapping bias correction method was selected for this study. SWAT was calibrated and validated before it was used for simulation purpose. The performance measures R2 and NSE for calibration (2000-2013) and validation (2014-2019) were 0.79 and 0.71 and 0.86 and 0.85 respectively. Mann Kendall (MK) trend testing was used to determine if a change is statistically significant and to detect trends in temperature and precipitation. According to RCP4.5 and RCP8.5, the emission scenarios predicted significant increasing temperature, but significant decreasing precipitation. Streamflow was simulated for two consecutive periods from 2020 to 2045 and from 2046 to 2071 for both scenarios and compared with the base period from 2000 to 2019 to explore the impact of climate change on Streamflow. The results indicated that the basin is likely to experience increased temperatures and altered precipitation patterns, whereas overall annual flow was projected to be significantly decreasing under SSP2-4.5 and SSP5- 8.5 emission scenarios in the mid and near future. These changes are likely to have major implications for water resources management in the region, particularly for agriculture, hydropower generation, and ecosystem services. The findings suggest the need for adaptive measures to address these impacts, including improved water management strategies and increased investment in climate-resilient infrastructure.
ASSESSMENT OF CLIMATE CHANGE IMPACT ON THE WATER BALANCE OF LAKE HAWASSA WATERSHED
(Hawassa University, 2023-07-25) KIFLE KARITE ONGOCHO
Assessing the climatic change impact on the water balance of a watershed is vital to develop sound management plans in current and future periods. The main objective of this study was assessing the climatic change impact on the water balance of Lake Hawassa watershed. The study was focused on the projection of climate variables, assessing the historical and future water balance components, and also evaluating the impacts of climate change on the stream flows of Lake Hawassa watersde. The Soil and water Assessment Tool (SWAT) mode was used for assessing the water balance components and to evaluate the climate change impact on the stream flows of Lake Hawassa catchment. SDSM (statistical downscaling model) was used under General circulation model set up for climate modeling. The water balance components of the watershed were computed in gauged and unguaged catchments. According to the SWAT model result in the gauged catchment, the historical average annual precipitation, surface runoff and the evapotranspiration (ET) were 1068.3mm, 155.11mm and 688.3mm respectively. In 2080 for RCP 8.5 the average annual precipitation, Surface runoff and ET will be 972.15mm, 143.17mm, and 812.19mm respectively. The climate change impact on the water balance components of Lake Hawassa watershed was evaluated for RCPs 2.6, 4.5 & 8.5 emission scenarios in the three time periods (i.e. 2020 (2022- 2040), 2050(2041-2070) and 2080(2071-2099). The result from climate model showed a general increasing trend for maximum and minimum temperatures and decreasing trend for precipitation in all the three time periods for all the three emission scenarios. The impact of climate change on the seasonal stream flows of the watershed will generally increases in the Kiremt season in 2020 and 2050 for all scenarios but decreases in Bega and Belg seasons for all time period in all RCPs. The future annual precipitation, Surface runoff, lateral flow, shallow groundwater recharge and water yield will be decreased up to 9 % and 9.9 % respectively and the increase in ET may reach up to 22% at the end of 2099 for RCP_8.5. Due to climate change the future water availability will be reduced in Lake Hawassa watershed. Therefore, the design and implementation of appropriate adaptation and mitigation strategies to the watershed by the decision makers may reduce the adverse effect of climate change.
Assessment of Groundwater Nitrate Level and Source of Pollution within Dire Dawa City, Dire Dawa, Eastern Ethiopia
(Hawassa University, 2017-10-19) MESFIN SAHELE
This 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 latrines
ASSESSMENT OF HEAVY METALS CONTAMINATION IN GROUNDWATER AND ADSORPTIVE REMOVAL OF IRON, MANGANESE, CADMIUM, COPPER AND ZINC USING PEAT MOSS: THE CASE OF KEMBATA TEMBARO ZONE
(Hawassa University, 2020-10-28) NATNAEL SHAMEBO
Heavy metal contamination is one of the most significant health issues. Heavy metals in groundwater were assessed and analyzed using atomic absorption spectrometer. The HPI, Cdeg and HEI indices were greater than their critical values of pollution indices. The result showed that Fe 2+ and Mn 2+ are the major groundwater contaminant's in the study area. Chemicals are mostly used to purify contaminated water. Adsorptive removal is most important to reduce heavy metals in water to acceptable levels and to minimize the cost of chemicals and health effects of chemicals. Thus, research was carried out to observe the effect of Sphagnum moss (peat moss) as non-chemical natural adsorbent. The Sphagnum moss was obtained from SNNPR, Kembata Tembaro Zone, Hambericho Mountain. The 500 and 1000 mg of peat moss were used to examine the effectiveness of peat moss to remove different concentration of iron, manganese, cadmium, copper and zinc. For removal of iron, manganese, cadmium, copper and zinc from contaminated boreholes and shallow wells water, batch experiment were employed. The contact time, pH, temperature and adsorbate concentration effects were studied during the adsorption of iron, manganese, cadmium, copper and zinc. The relationship between pH, time and concentration required adsorbing 5-15 mg/L of iron, manganese, cadmium, copper and zinc from the aqueous solution were observed. The average adsorption (93.72%) result indicated that there was a reduction of iron, manganese, cadmium, copper and zinc concentration in the water samples at pH 6.0. The 1000 mg peat moss was effective to remove 96.3% of 5 mg/L of iron, at pH 6, with the contact time 60 minutes. Adsorption equilibrium was attained after 60ࡋ minutes of contact time and it was described by kinetics studies. From (R2) values Zn 2+ and Cd 2+ best fit Langmuir adsorption isotherm model. All of the tested metals best fit Freundlich adsorption isotherm model.The model should be developed for large-scale treatment using peat moss for effective water purification