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Waterresources Potential Evaluation of Holeta River Catchement Centeral Oromia, West Shewa

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dc.contributor.advisor Ayenew, Tenalem (PhD)
dc.contributor.author Wogari, Ketema
dc.date.accessioned 2018-07-06T07:38:35Z
dc.date.available 2018-07-06T07:38:35Z
dc.date.issued 2006-06
dc.identifier.uri http://etd.aau.edu.et/handle/123456789/6877
dc.description.abstract The study area lies in the central part of the country, 45 km west of Addis Ababa, in Oromia National Regional state. It is a sub catchement of upper Awash drainage basin with a total surface area of 515 km2. Currently the need for water is highly increasing due to increasing population, irrigation practices, and agricultural based industry (particularly flower farming) in the area. Thus the main objective of this research is to study the status of water resources potential in the catchement. It is generally characterized with two major types of land forms: volcanic ridges and hills surrounding the catchement at its northern and eastern, part with flat land areas in central, western and southern part with humid climatic conditions and rivers that flow towards south. The basaltic lava flows (Alaji and Tarmaber Megeze formation); Trachyitic and Rhyolitic volcanic rocks, phyroclastic deposits and Quaternary Alluvial sediments are major geologic units in the area. On annual basis, the area has 1253.3mm; 748.2 mm, and 310.6 mm of mean total rainfall, Actual Evopotranspiration (AET), and groundwater recharge respectively, and is found under moisture surplus where by, precipitation satisfy soil moisture demand. The groundwater recharge from the annual precipitation in the area is very high. The Holeta River catchement is wide and very long. The land slope with in the catchement is very gentle. The outcrops in the area are highly fractured and jointed. Local minor faults and regional fractures are densely distributed in the area. There fore, recharge to the groundwater from the local precipitation with in the catchement is found to be high, so that groundwater storage of the area having alluvial sediments, weathered and fractured basaltic rocks and scoracious basalts as main aquifer and highly weathered basalt (paleosoil) layer as confining (barrier) is very high. The main recharge area of the study catchement are Fo’ata mountain range, Fo’ata mintile area Simbirtu kotu area, in the northern part, and Wechecha Menagesha mountain chain in the eastern part of the catchement, which are also located at higher elevation. These high lying areas get high rain fall compared to its surrounding low-lying area. Moreover, the groundwater movement in most places sub- parallel to the surface water flow and more or less controlled by the topography of the area. According to the hydro geological investigation under taken with in the catchement and as it has been revealed also from the yield of wells, the catchement is categorized in to four permeability and productivity zones. The high permeability and productivity areas (yield ≥ 10 l/s), moderate permeability and productivity (yield 5-10 l/s) low permeability and productivity (yield 2-5 l/s), and poor permeability and productivity (yield < 2l/sec). The water samples analyzed in the area have 15.5 oc to 24.7 oc and less than 1000 mg/l of temperature and TDS respectively, eventhough they show progressive increase along the flow path. In all analyzed samples calcium is the dominant cation and bicarbonate is the dominant anion. The water in the catchement is mainly of Ca-Mg-HCO3, Ca-Na-HCO3 and Ca.HCO3. Almost all the analyzed water samples are with in the limit of acceptable value of WHO (World Health organization) water quality standards for water supply and irrigation. In general the current water resource potential (quantity and quality) of the catchement for domestic, agricultural, and industrial is evidently enormous. How ever the long term sustainable use of this resource requires an integrated effort of all concerned professionals and departments and the inhabitants of the whole population of the catchement and its surroundings as to how to use and protect the soil- water- forest system in the catchement as it is very decisive in the fate of the future generation. en_US
dc.language.iso en en_US
dc.publisher Addis Ababa Universty en_US
dc.subject Catchement Centeral Oromia en_US
dc.title Waterresources Potential Evaluation of Holeta River Catchement Centeral Oromia, West Shewa en_US
dc.type Thesis en_US

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