Addis Ababa University Libraries Electronic Thesis and Dissertations: AAU-ETD! >
Faculty of Science >
Thesis - Earth Sciences >
Please use this identifier to cite or link to this item:
|Title: ||GEOELECTRICAL CONSTRAINTS FOR GROUND WATER MODELS AROUND LEGEDADI, NORTH EAST OF ADDIS ABABA|
|Authors: ||MENGESHA, SISAY|
|Advisors: ||Dr. Shimeles Fisseha|
|Keywords: ||Earth science|
|Copyright: ||Nov-2008 |
|Date Added: ||3-May-2012 |
|Abstract: ||Geophysical surveys were carried out around Addis Ababa namely on the Ada’a plain, the
Becho plain and different traverses with different orientations in the Abay plateau by Water
Works Design and Supervision Enterprise (WWDSE). The methods employed were electrical
resistivity sounding, electrical resistivity imaging and magnetic mapping. The study mainly
focuses on the evaluation of the groundwater potential of Ada’a and Becho plains and was
designed for the purpose of pressurized irrigation development.
In this thesis work, only electrical resistivity sounding method is employed and the study area is
restricted along a transverse of Gohatsion-Chancho-Sululta-Legedadi-Adaa which is located
between 9004’78’’& 9056’58’’N and 38027’29’’ & 38054’67’’E. The study aims to map the
possible paths of fluids and to develop geoelectrical models of a given area interms of ground
water studies. This includes detail reprocessing and analysis of the existing data. And to acquire
practical experience in the interpretation of resistivity data.
From the pseudosection along profiles and the sliced depth section at different depth levels show
the northern part is relatively resistive than southern part. This may indicate the thickness of the
hard rock pledges southward or an extended conductive response of the overburden.
The interpreted result of the individual VES points and the two geoelectric sections shows, in the
northern flank there is a favorable condition to aquifer shallower than the southern flank. But
thick aquifer is observed on the southern flanks as compared to the northern flank. The graphs
obtained from hydrodynamic data also confirm this result. And the ground water flows from
north to the south direction.
The depth of investigation attained by the resistivity data was not deep enough to penetrate
the lower volcanic aquifer. Therefore the use of deep probing, natural source EM
geophysical methods such as controlled source or conventional Audio Magnetotelluric
(CS/AMT) is recommended. Besides, the potential methods (gravity and magnetic)
integrated with other techniques such as remote sensing in GIS framework are
recommended to come up with full picture of the subsurface map of the survey area.
Generally results from vertical electrical soundings as obtained from the stacked graphic plot,
pseudosections and geoelectric section analysis show that northern flank is relatively resistive
than the southern part. Therefore, from the hydrogeological point of view the southern part
deserve more interest for ground water exploration.|
|Appears in:||Thesis - Earth Sciences|
Files in This Item:
|90||944.41 kB||Adobe PDF||View/Open|
Items in the AAUL Digital Library are protected by copyright, with all rights reserved, unless otherwise indicated.