Water Resource
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Item COMPARISON OF SWAT AND WEPP FOR MODELING ANNUAL RUNOFF AND SEDIMENT YIELD AND QUANTIFCATION OF NUTRENT LOSS IN AGEWU MARIYAM WATERSHED, NORTHERN ETHIOPIA(Hawassa University, 2022-10-22) YALELET ABIE WORKUUnevenly heavy rainstorms during the rainy season create runoff and soil erosion which affects soil fertility and production, especially in northern Ethiopia. In this study soil and water assessment tool (SWAT) and geographic water erosion prediction project (GeoWEPP) were applied to compare estimation of annual runoff and sediment yield and quantification of nutrient loss in Agewu-Maryam watersheds eastern Amhara, region, Ethiopia. To run both models, need spatial and temporal data distribution is required as an input. The soil textures and other selected soil properties were determined in the field and the laboratory and a soil map were derived from the digital soil map of the world. A land-use map was prepared based on manually digitizing from Google earth image. A Digital Elevation Model of the watershed was used for delineating the watershed and preparing a slope map. ArcGIS 10.4 was used for both models for basic interface for further analysis. During each runoff event, runoff samples were collected and the sediment concentrations were analyzed in the laboratory. The simulation result of long-term (24-year) average means annual runoff and sediment yield from WEPP and SWAT models were estimated. The results were performed well as indicated by R 2 0.86 and 0.91 and with NSE 0.54 and 0.71 for monthly runoff were satisfactory for SWAT and WEPP models compared with observed value respectively The estimated average mean annual runoff and sediment yield at the outlet of the watershed was 65.54mm and 146.14mm and 43t/ha/yr and 41.7t/ha/yr respectively for WEPP and SWAT models. The t statics result shows that there is no statistically significant difference with p-value (0.97 for runoff and 0.98 for sediment) between the two models' simulation results. Some of the Sub watershed were identified and prioritized as more susceptible to soil erosion and give more attention first to this area for reducing runoff and soil erosion. The total nutrients loss within the suspended sediment were 33.74kg/ha/yr N,6.79kg/ha/yr P, 642.5 OM kg/ha/yr, and 1.52 K for the watershed. Hence SWAT and WEPP models were well suited for the estimation of annual runoff and sediment yield. The sediment yield simulated from both models was high which was alarming and far beyond the soil loss tolerable rate. Therefore, the result of the model could be used as a decision-making toolItem ASSESSMENT OF WATER DISTRIBUTION NETWORK OF ADOLA WAYOU TOWN WATER DISTRIBUTION SYSTEM(Hawassa University, 2022-10-21) SOLOMON SEYOUM DAMISSEWater distribution systems are designed to fulfill all requirements of water demand needed for decades. Initial system designs frequently consider any anticipated changes likely to happen. However, as times elapsed they slowly begin to fail to satisfy customer’ requirement; both in quantity and quality. This research was conducted by aiming to undertake the assessment of water distribution network of Adola Wayou Town for existing water distribution system which is located southern Oromia region of Ethiopia. The main objective of this research study was to investigate the states of the existing water distribution system by assessing water demand, and water production, hydraulic parameter analysis and water loss and the cause in the distribution system. The research depend on the secondary and primary data which was collected from design document, literature, journals and reports, field observation, interviews and discussion with water utility office to analysis water loss and the cause and water service coverage. The town water distribution network had been analyzed using computer model Water GEMs connected edition under both steady-state and extended period simulation for the present population scenarios. The simulation result of the model for maximum and minimum pressure and velocity was used as the base to analysis the hydraulic performance of the water network during peak hour consumption times and low consumption times. From the analysis result about 11.62% of the nodes have the negative pressure. Additionally, the model output results indicate that about 63 pipe in water network system has the velocity below minimum requirement of 0.6m/s during peak hour consumption time. The total domestic and non-domestic water demand of town was 3421.12m3 /day. From the water produced from the treatment source the non-revenue water in the town water system was considered as 31.93% of distributed water in distribution system. The actual/real water loss share large volume that accounts about, 312,545.2m 3 /year whereas the apparent loss 60,412.79m 3 /year. The finding of the study showed that the service coverage and average connection per family of the town were estimated in the order of 62.65% and 41% respectively. In general the result of the research study of water distribution network system indicates that Adola Wayou Town water utility office under current situation was inefficient. Accordingly it’s required to provide efficient and more reliable water system through pressure zoning, improving pipe size, and planning another water distribution system, giving more attention to water loss reduction police and strategies to reduce the waste actual/real and apparent lossItem PERFORMANCE ASSESSMENT OF URBAN DRAINAGE SYSTEM USING STORM WATER MANAGEMENT MODEL (SWMM): THE CASE OF ALETA WONDO TOWN, SIDAMA REGIONAL STATE(Hawassa University, 2022-07-22) SAMUEL YONKORAThe drainage system were one of the most important factors to be considered in the urban drainage infrastructure plan. Now in adequate urban storm water drainage problems represent one of the most common source of compliant numerous town of Ethiopia. Drainage problem in Aleta wondo Town is the worest issue of over flooding on the surface runoff at highly rainfall season. Unfortunately, street flooding and overtopping drainage system problem are occurring at the rainy season in a Town.The main objective of this study was to assess the hydraulic performance of drainage system Aleta Wondo Town. The study employed both primary and secondary data collection from the field surveying work was conducted to inspect the existing drainage condition and to measure channel geometric conditions. The meteorological approaches employed in this study include, the identification of the existing drainage network flow direction and delineation of contributing area. The Storm Water Management Model( SWMM5.1) was applied to simulate the water level in the links and junctions. The simulated result indicate that 1.162m3 /s average flow rate,1.632m3 /s maximum flow rate and 12.457*103 m 3 total annual volume runoff. The hydrological analysis was computed by the the rational method. The result shows the existing drainage system of Aleta Wondo Town were not well connected drainage lines and silted by different waste material because of the capacity of drainage system can‟t handle the current runoff that flows over the area. Therefore, some adjustment or improvement to give the best service and needs a series of regular maintenance and drainage should be well designed and constructed to the standard and managed properlyItem ASSESSMENT OF METEOROLOGICAL DROUGHT BY USING THE SPI INDEX: A CASE STUDY IN CENTRAL RIFT VALLEY OF ETHIOPIA(Hawassa University, 2022-04-28) BEREKET DESELEGN ASHEBODrought is a complex and recurring phenomenon that has impacts on agriculture, water supply, and ecosystems. Even if its characteristics vary significantly from one region to another, and differs from aridity that is a permanent feature of climate restricted to low rainfall areas drought occurs in all climatic zones. Therefore, it is very important to increase the understandings of the concerned body and local community in the continent in general and in Ethiopia in particular for future most likely drought impacts. The objective of this study was to identify the past and projected meteorological drought by using the standardized precipitation index, in case of Central Rift Valley of Ethiopia. For this study 34 years historical precipitation data from (1985-2019) and (2020-2100) years projected climate data were used for analysis. RStudio software was used to calculate SPI at the nine major station to identify historical and future meteorological drought. The Mann-Kendall trend test and Sen’s slope estimate were employed to find the nature of the drought, rainfall and temperature trend and significance level in the study area. Results showed that the study area was under drought condition in (1991-1992), (2015-2016), (2017-2018) and 2019 in historical period and for projected period in near future (2022, 2029 and 2046) in mid future (2058, 2065 and 2061,2068) in far future (2099, 2085 and 2099,2083) which were among the drought years for both RCP4.5 and RCP8.5 respectively. For historical data SPI-3 showed that 325 moderate, 141 severe and 87 extreme droughts events. Again, 3-month standardized precipitation index showed that 392 moderate, 171 severe and 95 extreme droughts events for RCP4.5 and 456 moderate, 142 severe and 80 extreme number of drought events occurred for RCP8.5. Statistical analysis for historical data showed increasing trends of drought at three-month timescale in Langano and Ziway station but decreasing tendencies in Tora, Kulmsa, Koshe, Degaga and Arsi Negele stations at significant level of (p < 0.05). RCP 8.5 shows significantly decreasing trend with the S-test of -158 and with the Z-value is |Z|> 1.96 at near future, (S-test= -122, Z=-2.3) at far future for 95% confidence level. But RCP4.5 shows decreasing trend at mid future (S-test=-106, Z= -1.67). Finally, from the result we conclude historical drought and projections indicated that its intensity, severity and duration is increase under past data as well as for both analyzed RCPs (RCP4.5 and RCP8.5).Item PERFORMANCE EVALUATION OF THE BILATE AND FURFURO IRRIGATION SCHEMES IN SILTI ZONE, SOUTHERN ETHIOPIA(Hawassa University, 2022-10-22) MULUGETA ABEBO ABOThis study attempts to evaluate the performance of the Bilate and Furfuro irrigation schemes in Silti Zone, Southern Ethiopia using internal and external performance indicators. To achieve the aim the primary and secondary data were gathered. Two schemes were evaluated by their own merits using internal performance indicators and a comparison was also made using external performance indicators. For field data measurements three farmers’ fields were selected at the head, middle, and tail-end of each scheme. The results of analyses revealed that average field application, water storage and overall irrigation efficiencies were 55.9 & 58%, 53 & 46.5% and 28 & 32% for Bilate and Furfuro schemes respectively. This implied that the two schemes were performing inefficiently and inadequately, but, water distributed uniformly. The results obtained for conveyance efficiencies implied that most canal sections had unreasonable losses of water in two schemes. The results of external indicators show that, RWS, RIS, WDC, OPUIA, OPUCA, OPUIS, OPUWC, SIA and IR were 0.68 & 0.79, 0.61 & 0.77, 0.66 & 0.53, 4140.4 & 1781.5 $/ha, 4510.3 & 1968.5 $/ha, 0.94 & 0.28 $/m3 , 0.99 & 0.39 $/m3 , 1.05 & 1.02, 1.11 & 1.09 for Bilate and Furfuro schemes respectively. This revealed that the applied water was not satisfied the crop water demand, but their irrigated lands were expanded for two irrigation schemes. Furfuro scheme was better than Bilate in terms of relative water supply and relative irrigation supply, but their results obtained were below acceptable values. However, Bilate scheme had significantly better land and water productivity than Furfuro scheme due to used high value crops, better agricultural inputs and removal of grass cover and sedimentation from canal systems. Hence, Bilate irrigation scheme was better performing than Furfuro scheme. Therefore, adopt the best practices learned from Bilate irrigation scheme for the Furfuro scheme. Moreover, properly maintain malfunctioned infrastructures, create WUAs and agricultural experts, and create awareness for farmers and WUAs on irrigation water management in two schemes.Item EVALUATION OF SMALL SCALE IRRIGATION SYSTEM IN WESHA SOYAMA VILLAGE IN SIDAMA REGIONAL STATE(Hawassa University, 2022-10-22) ABEL IYASU ANCHISOField assessment to evaluate water use efficiency of small-scale irrigation projects plays a vital role in improving the existing projects and assist engineers in designing new systems so that irrigation practice becomes sustainable. Therefore, this study was carried out to evaluate the performance of Wesha SSIS using internal and external performance indicators. This study used primary and secondary data for assessing the irrigation performance. The primary data collected includes field observation, soil samples to characterize the soil in terms of physical characteristics and discharge measurement at main and field canals. Secondary data collected were total yield, area irrigated, crop type, and climate data. CROPWAT 8.0 model was used to calculate ETo and the crop water requirement. The analysis of internal performance indicators showed that the conveyance, application, storage efficiencies, distribution uniformity, and overall irrigation efficiencies were calculated and the results were 66.43, 46.70, 96.02, 91.88 and 31.02% respectively. Since the overall scheme efficiency at the study area was 31.02%, which was very poor; which mean that irrigation water loss was very large indicating need for scheme improvement. The analysis of water related indicators such as RWS and RIS were found to be 1.35 and 1.14 respectively. Since the value of RWS and RIS is greater than one this implies that, there were sufficient relative irrigation supply and high relative water supply which was beyond the crop demand. This shows that it could irrigate additional farm land with this delivery amount and available effective rainfall in the study area. The value for WDC at the study area was found 1.08 this implies that, the river diversion infrastructure is capable of delivering the necessary peak water demand. Agricultural related indicators such as, the output per unit command area is 38,939.2 Birr/ha and output per unit irrigated area is 139,068.6 birr/ha. Water productivity indicators such as, Output per unit water consumed and Output per unit irrigation water supplied are 45.24 birr/m3 and 0.15 birr/m3 in Wesha SSIS respectively. Based on the results obtained can be concluded that the agriculture production indicators are found to be reasonable. The potential evapotranspiration of the study area, calculated using CROPWAT Model, is more than the effective rainfall in most of the months calling for supplemental irrigation. The effective rainfall is more than ETo by 10.96 mm/month during July; meaning that no irrigation is required during this month. Therefore, those farmers who grow crops on July are less likely to apply supplemental irrigation. On the other hand, extensive irrigation is essential for crops planted particularly on October, November, December, January, February, March, April, May (with 84.67, 96.9, 100.16, 82.86, 93.2, 85.15, 88.07 and 53.95 mm of irrigation water requirements, respectively). During the study period, on-site soil erosion, temporary water logging and illegal canal breaching are the observed major problems associated with the farmers’ irrigation practices. Weak operation and maintenance of the project is also witnessed. Since the current irrigable area is below the irrigable area at the initial period of the irrigation scheme, thus the project is not sustainable; due to the fact that SIA is much far from 100%. Settlement expansion is the major reason observed in the field as threat to the sustainability of the projectItem ASSESSMENT OF SUSTAINABILITY OF RURAL WATER SUPPLY SCHEMES: A CASE STUDY OF DAMOT GALE WOREDA, WOLAITA ZONE, SOUTHERN ETHIOPIA(Hawassa University, 2022-03-24) GELAN GASHO MALAKOThe Sustainability Development Goal targets to reduce the proportion of people without sustainable access to safe drinking water, but huge disparities still exist. The main objective of this study was to assess the main factors affecting the sustainability of rural water schemes in the Damot Gale Woreda. The main factors considered were: water usage, water quality, time spent to collect water, service provision, service interruption, water tariff, willingness to pay, management factors, choice of technology and environmental factors. Data was collected using questionnaires, focused group discussion, field visits and key informant interview. Statistical Package for Social Sciences (SPSS) was used to analyze the data and to calculate sustainability scores for water schemes. The analysis showed that the average daily water usage was below the mean, i.e 20 to 40 liters/ household. About 75.47 % of the beneficiaries spent more time to collect water than the standard (30 minute round trip). About 73.21 % of the beneficiaries were dissatisfied with the absence of operator during water collection. About 57 % of beneficiaries answered there were service interruptions because of system failure rated at 77.74 %. About 50.18% of water users perceived taste and odor problem. About 23.02 % of beneficiaries argued that the newly set tariff was expensive and 34.34 % are not willing to pay. The results indicated that the main factors which made the schemes unsustainable were: long fetching time; service interruption due to scheme failure; new water tariff; willingness to pay and commitment of all members. Water service providers and the community should address the identified affecting sustainability factors in their conception, planning, construction and post construction management activities of rural water supply schemes. Therefore, the findings call for adopting demand responsive approach, strengthening community participation, building community capacity to manage water supply schemes properly, establishing effective user fee collection system, developing trusted and transparent system of funds management, choosing appropriate technology, building local technicians' capacity, minimizing problems related with availability of spare parts, improving construction quality as well as strengthening the capacity of the leading office at Woreda level to support rural communities in managing water supplyItem PERFORMANCE EVALUATION OF URBAN WATER SUPPLY SYSTEM; A CASE OF JIGJIGA TOWN, SOMALI REGIONAL STATE, ETHIOPIA(Hawassa University, 2022-10-22) ABDURAHMAN ALI AHMEDIn most developing countries, such as Ethiopia, problems with urban water supply and demand are common. The purpose of this thesis was to assess the present urban water delivery system in Jigjiga Town with the major goals of identifying issues with the Jigjiga Town water system by evaluating the current status of the town's water supply system, evaluating the WSS hydraulic performance, and finally propose corrective solutions. The present situation was assessed using the gap between the town's supply and demand by forecasting its population, while water losses were calculated using the difference between production and consumption data. In addition, WaterGEMS software was utilized to construct the model in order to examine the current water supply and distribution system. The model was used to adjust the high and low-pressure zones at junctions, as well as the velocity through the pipe. To explore the system model, the model was run for steady-state simulation and extended period simulation. According to the results of the research, the Town's water supply just covers 64% of demand. This result indicates the prevalence of demand-supply gap. Furthermore, the average loss from three years of production and consumption observation was 36 %. Moreover, the system has issues of over and under pressure, with utmost pressure occurring at extended period simulation (EPS) at PHD being 69mH2O, which is under the suggested range, and 83.5 % (182 points) of the velocity in the pipes being less than 0.5m/s. To deal with these issues, additional pumps must be installed to enhance production, existing well sources must be rehabilitated, and the capacity of the distribution pipeline must be increased by installing new pipesItem IMPACT OF CLIMATE CHANGE ON THE GROUNDWATER HYDROLOGY OF LAKE ZIWAY WATERSHED, ETHIOPIA(Hawassa University, 2022-10-23) MIERAF ABEBE DONKAClimate change poses uncertainties to the supply and management of water resources. The relationship between the changing climate variables and groundwater is more complicated and poorly understood. Groundwater resources are related to climate change through the direct interaction with surface water resources, such as lakes and rivers, and indirectly through the recharge process. The impact may be worse for developing countries like Ethiopia because of their economies are strongly dependent on basic forms of natural resources. This thesis presents the likely impact of climate change on groundwater hydrology of Lake ziway watershed located in the Rift Valley basin of Ethiopia, The RCP scenarios of types 4.5, and 8.5 were used for the climate projection from the CORDEX Africa domain from CMIP5. The RCM of RCA4 was used to generate future possible local meteorological variables in the study area. These data were used as input to the Soil and Water Assessment Tool (SWAT) model to simulate the corresponding future streamflow Variability in the Ziway watershed. SWAT-CUP, a program for calibration and uncertainty was utilized for uncertainty analysis. The two projected time periods for this study were the 2040s, and 2070s. In the Lake Ziway watershed, there exists a climate change in the study period of 1989-2019. Since, there is a significant change from the base period to the projected time periods, therefore there would exist a climate change impact for the projected time periods under both scenarios in the Lake Ziway watershed. Therefore, climate change shows a significant decreasing impact on the groundwater flow of Lake Ziway watershed, which in turn affects the level of Lake Ziway significantlyItem EFFECT OF DEFICIT IRRIGATION UNDER DRIP IRRIGATION METHOD ON THE YIELD AND WATER USE EFFICIENCY OF ONION (Allium cepa L.) AT FOGERA DISTRICT, NORTHWESTERN ETHIOPIA(Hawassa University, 2022-12-20) MISGANAW YIMER TESSEMAWater has been identified as one of the scarce inputs, which can severely restrict agricultural production and productivity unless it is carefully conserved and managed. Deficit irrigation improves water productivity and irrigation management practices resulting in water saving by maintaining soil moisture content below optimum level throughout growth season. Hence, a field experiment was conducted in Amhara region, South Gonder zone, at Fogera district during the dry season of 2020 using deficit irrigation under drip irrigation method to evaluate the effect of deficit irrigation practices on yield and water use efficiency (WUE) of onion. The experiment was carried out in randomized complete block design with three irrigation treatments (drip irrigation at 100%, 80% and 60%ETC) and three replications. Drip irrigation at 100%ETc gave very highly significant onion yield (26.8 t ha-1 ), as compared to 80% and 60%ETc irrigation treatments. However, irrigation water use efficiency was found highest (6.2 kg m -3 ) with drip irrigation at 80%ETc. The amount of water saved at 80% and 60%ETc under drip irrigation method were 90mm, and 179.9mm respectively over 100% drip irrigation method and this may sufficient to irrigate 0.2 to 0.4 hectare of additional area of onion crop as compared to that of 100%ETC drip irrigation method. Therefore, this study suggests that farmers in the study area, having limited amount of water for irrigation, should adopt deficit irrigation under drip irrigation method.
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