Impact Assessment of Irrigation Water Use on Lake Ziway Water Level

dc.contributor.advisorFikreselasse, Daneal(PhD)
dc.contributor.authorGirma, Habtamu
dc.date.accessioned2018-07-23T08:18:18Z
dc.date.accessioned2023-11-11T08:32:43Z
dc.date.available2018-07-23T08:18:18Z
dc.date.available2023-11-11T08:32:43Z
dc.date.issued2015-09
dc.description.abstractThe study area is located in the central rift valley lake basin of Ethiopia. This area has a fresh water lake called lake Ziway but this precious resource is endangered due to abstraction directly from the lake and from feeder rivers (Meki and Katar). This research was intended to show the impact of irrigation water use on lake Ziway water level. The methodology used was CROPWAT 8.0 model to estimate the irrigation water requirements of five major crops irrigated in the study area. Bathymetric data was used to analyze the impact of irrigation water use on the level of the lake. River inflow and outflow data were collected, precipitation and evaporation data were estimated from mean monthly rainfall and annual evaporation data respectively to compare percentage reduction of initial volume of the lake without considering irrigation water abstraction with irrigation water abstraction condition. The results showed that for the whole existing and potential irrigation development area crop water requirements were 197,844,647.3m3. This much irrigation water abstraction holds 9.31% of initial volume of lake Ziway and it reduces 0.4m water level of the lake annually. This much rate of lake level reduction (0.4m/year) may lead to the loss of the lake after 27.5 years and it may also become the cause to cease the downstream flow after 6.25 years. And again, the results showed that regardless of irrigation water abstraction only 7.74% of the initial volume of the lake was reduced, but when irrigation water abstraction was considered 17.05% of the initial volume of the lake was reduced and this showed that irrigation water abstraction merely reduced 9.31% of initial volume of the lake which indicated greater reduction due to irrigation water abstraction relative to reduction with no irrigation water use condition (7.74%). These all results revealed that irrigation water use for the whole existing and potential irrigable area brings drastic impact on the lake Ziway and the downstream area that benefit from the lake. Therefore, the study area needs integrated water resources management to sustain the life of the area. Key Words: Impact, Lake Ziway, Gross irrigation water requirements, Irrigation water abstraction, Lake level reduction, Downstream areaen_US
dc.identifier.urihttp://etd.aau.edu.et/handle/12345678/9745
dc.language.isoenen_US
dc.publisherAddis Ababa Universityen_US
dc.subjectImpacten_US
dc.subjectLake Ziwayen_US
dc.subjectGross irrigation water requirementsen_US
dc.subjectIrrigation water abstractionen_US
dc.subjectLake level reductionen_US
dc.subjectDownstream areaen_US
dc.titleImpact Assessment of Irrigation Water Use on Lake Ziway Water Levelen_US
dc.typeThesisen_US

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