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Please use this identifier to cite or link to this item: http://hdl.handle.net/123456789/2165

Advisors: Dr. Seifu Kebede
Keywords: Central Rift Valley Lakes,
WEAP model,
Lake Abiyata
lake level change.
Copyright: Jun-2009
Date Added: 3-May-2012
Abstract: ABSTRACT The Study was conducted in Ziway-Abiyata Catchment in the Central Rift Valley of Ethiopia, to assess the effects of current and future water use practices on the hydrology mainly lake level change of the Lake Abiyata and its surroundings using a WEAP model. Records of hydrology, meteorology, irrigation, domestic water supply and industrial water supply for the study area have been statistically tested and arranged as an input data source to fit the model. Hydrologic and climatic data were correlated with lake levels. The demand and the supply of water resource, base line data and the future development activities of the area were compared using mainly three different scenarios SN1, SN2 and SN3. While by altering the priority settled for the Bulbula River s flow to a least priority level, additional three scenarios SN11, SN22 and SN33 were generated. The results revealed that unless the minimum historical flow requirements are maintained, all scenarios indicated the future effects on Lake Abiyata. For the SN1, the lake level declined by 0.79 m and 0.34 m for Ziway and Abiyata lakes respectively. While compared with the baseline scenario, in the SN11 the lake level drops were 2.61 m and 0.59 m for Abiyata and Ziway lakes respectively. The SN2 scenario revealed a decline by 0.89 m and 0.42 m for the Lake Ziway and Lake Abiyata compared with the baseline scenario respectively. But in the SN22 scenario, a maximum level drop over the simulation period of 3.5 m and 0.7 m below the mean value of the existing condition for Lake Abiyata and Lake Ziway respectively was predicted. The SN3 option had less level drop effect compared with the SN2 scenario for both lakes despite the additional level drop by this development. The lake level drop below the natural sill in Lake Ziway may result in the total dry up of the Bulbula River, which consequently threatens Lake Abiyata s existence as a permanent lake. Similarly, compared with the lake baseline mean lake level, the Abiyata Soda Ash Enterprise expansion will drop the Abiyata Lake level by about 0.09 m, which was less than the effect due to upstream irrigation development proposition in a general sense. It is necessary that more detailed resource assessment of water should be done, including sustainable abstractions (safe yields) and the spatial variability of water quantity. In addition to this, the new projects on the study area demand Integrated Water Resources Management and Environmental Impact Assessment before the realization of the projects.
URI: http://hdl.handle.net/123456789/2165
Appears in:Thesis - Environmental Sciences

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