Institute of Technology
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The Institute of Technology focuses on education, research, and innovation
in engineering, technology, and applied sciences to support sustainable development.
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Item GROUNDWATER FLOW MODELING AND ASSESSING THE IMPACT OF FERTILIZERS ON GROUNDWATER QUALITY: THE CASE OF HORMAT-GOLINA SUB-BASIN, AWASH BASIN, ETHIOPIA(Hawassa University, 2019-10-23) MENGESHA TESFAW ABAYGroundwater is the source of water supply for different purposes including domestic, irrigation and depending on its capacity, it is suitable for industrial activities. Groundwater in many parts of the world is under risk because of increasing demands, mismanagement and contamination. All previous studies had not been explored the predicted groundwater flow dynamics in relation to climate change and anthropogenic stress, but this study has developed on the groundwater fluctuation with respect to human pressure and climate change. Visual mod flow flex 5.1 was used for simulating the groundwater flow in response to different stress periods. Groundwater flow and transport modeling in this Sub-basin have provided information about groundwater quantity as well as the quality aspect for decision makers about the groundwater accessibility. The initial head measured values in before and after irrigation season has varied to a maximum of 0.8 m. The groundwater head level in before and after irrigation season was varied from 9.3 m to 8.26 m in the Southern boundary and from 41.5 m to 38.83 m in Northwestern boundary of the Sub-basin respectively. While the predicted groundwater head and drawdown of increased pumping rate with decreased recharge rate scenario was magnify the bad effects in the Sub basin. The maximum depth of 0.27 m and 2.6 m drawdown was found in before and after irrigated season around the pumped wells respectively. The increased pumping rate with decreased recharge rate was replied to the groundwater head at the end of 2021has decreased by 2.81 min the Northwestern boundary of the Sub-basin as compared as using constant pumping rate with constant recharge rate. While decreased pumping rate with increased recharge rate was replied to the groundwater head at the end of 2021has increased by 2.23 m in the Northwestern boundary of the Sub-basin as compared as using constant pumping rate. The impacts of climate change and human pressure on groundwater have been the greatest threats in those supply wells. Decreased in pumping rate with increased recharge rate has accomplished to restore and protect the groundwater resources which is the best option for groundwater restoration and monitoring. Anthropogenic pressures including the application of fertilizers were a considerable cause of degraded groundwater quality in relation to Nitrate and Phosphate concentration with series of time. The groundwater quality has deteriorating with the applied Urea and DAP fertilizes in the selected wells of Hormat-Golina Sub-basin. Farmers have encouraged using practices that minimize the risk of groundwater pollution by carefully controlling and timing of the use of fertilizers to avoid over application.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 latrines