Browsing by Author "Zelalem Zerihun"

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    Groundwater Potential Assessment and Hydrogeochemistry of Upper Dhungeta and Ramis Sub-Watersheds, in Case of Oromia Regional State, West Hararghe Zone, Ethiopia
    (Addis Ababa University, 2022-12) Zelalem Zerihun; Tilahun Azagegn
    The main sources of water for domestic water supply of Bedesa, Gelemso, kara, wachu towns, Boke woredas and neighboring rural villages is Upper Dhungeta and Ramis Sub-watersheds where are found in the eastern escarpment of the rift valley on the upper part of Wabishebele river basin. Despite their importance, the hydrogeological and hydro geochemical system of the sub-watersheds is not well understood. This study was aimed to assess the groundwater resource potential and Hydrogeochemistry by identifying and characterizing the main aquifer types of the sub-watersheds, estimating the natural groundwater recharge, determining ground water flow directions, identifying geochemical evolution and suitability of the water in the sub-watersheds for different purposes. Well log data and hydraulic parameter values obtained from constant pumping test data were used to identify and characterize the aquifers in the sub-watersheds. For estimation of the natural groundwater recharge, soil water balance method was used. Groundwater flow directions also were determined from the groundwater contour map prepared by GIS software using groundwater level data. The study has indicated that there are three major types of aquifer types in the sub-watersheds namely Extensive and Moderately Productive Porous Aquifers, Extensive and Highly Productive Fissured Aquifers and Extensive and Moderately Productive Fissured Aquifer. From the computed meteorological data, the amount of water infiltrated to subsurface as a recharge was 101.2mm. Moreover, groundwater flow runs locally towards the low lands (Bedesa graben) which is considered as discharge area. Yet, regionally it flows from the west to east and southeast directions of the sub-watershed. Finally, Physical parameters measurement, and chemical analysis of water samples were analyzed to study the geochemical evolution of water in the area and the Ca-Mg-HCO3 type is the dominant water type which indicates recharge area ground water with less time of residence and interaction with the surrounding rock/soil. Finally, by comparing with different standards and guidelines, Groundwater in the area is suitable for Domestic, Agricultural and Industrial purposes.