Integration of Remote Sensing and Gis for Groundwater Resources Assessment in Moyale-Teltele Sub Basin, South Ethiopia
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Date
2007-03
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Addis Ababa Universty
Abstract
An integrated approach with remote sensing and Geographic Information
Systems (GIS) was adopeted to assess the groundwater potential in the
southern lowlands of Ethiopia, Moyale-Teltele sub-basin of the Genale Dawa
river basin. Six geologic, physiographic, and hydrologic factors were applied
namely: lithology, structure, geomorphology, slope, land cover, and drainage.
Digital Elevation Model (DEM) acquired from Shuttle Radar Topography
Mission (SRTM) was used to derive contour and geomorphology, where
contour is also used to generate slope. Landsat ETM scenes covering the area
were classified for landcover. Other maps were digitized from different
sources. Water point inventory was done in selected wells and springs to
collect data on location, depth, water level, and yield. Satty’s Analytical
Hierarchy Process was utilized in giving ranks and weights to the layers and
different classes in them. Weighted Overlay Analysis was implemented in
ArcGIS to combine the thematic layers and produce the groundwater potential
map of the area. This result was further verified by groundwater yield data of
boreholes and springs collected in the field and from previous reports. The
validation revealed that the result was in well conformity with the actual yield
of the wells and springs.
The spatial distribution of groundwater potential zones showed regional
patterns related to geologic, physiographic, and hydrologic characteristics of
the area. Quaternary alluvium deposits and Quaternary volcanics were
obtained to be situated in very good groundwater potential zones. The SE-NW
trending geological structures affected most of the tertiary volcanics which
appeared in the very good to good potential zones. Plain landforms and very
low slope areas dominate the very good to good groundwater potential zones.
The very good groundwater potential zones have very low drainage density.
Agricultural lands and wood lands cover most of the very good to good
groundwater potential areas. Groundwater potential zones demarcated
through the model are in good agreement with borehole and spring yield
data. The result demonstrate that the integration of remote sensing and GIS provide a powerful tool in the assessment and management of water
resources.
Key Words
Geographic Information Systems, Remote Sensing, Multicriteria Decision
Evaluation, Groundwater, Rank, Weight, Moyale-Teltele
Description
Keywords
Geographic Information Systems, Remote Sensing, Multicriteria Decision Evaluation, Groundwater, Rank, Weight, Moyale-Teltele