Assessment of Potential Groundwater Zone Using Integrated GIS and Remote Sensing Techniques in Sekota Wereda, Northern Ethiopia.
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Date
2018-09
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Addis Ababa University
Abstract
Due to complex and erratic nature of groundwater occurrences in volcanic rock terrains,
groundwater development in form of boreholes/wells without the necessary pre-drilling
hydrogeological investigations usually results in failure. Therefore, there is the need for adequate
characterization of aquifers and delineation of groundwater potential zones in such volcanic rock
setting. This study employed the integration of multi-criteria decision analysis (MCDA), remote
sensing (RS) and geographical information system (GIS) techniques to delineate groundwater
potential zones in volcanic rock terrain of N-Ethiopia, Amhara Regional State, Wag Himra Zone
of Sekota Wereda, and validation of the result with existing borehole/well yield data. The study
approach involved integration of seven different thematic layers (lithology, land form, soil,
drainage density, lineament density, land use and slope) based on weights assignment and
normalization with respect to the relative contribution of the different themes to groundwater
occurrence using Saaty’s analytic hierarchy approach. Following weigh normalization and
ranking, the thematic maps were integrated using ArcGIS 10.1 software to generate the overall
groundwater potential map for the study area.
Finally, groundwater potential zones are classified into three categories namely low, moderate,
and high zone. It is observed that 10.03% (167.5 km2) of the study area falls under ‘low’
groundwater potential zone. Approximately 1190.8 km2 area accounting for 71.4% of the study
area falls under ‘moderate’ category and ‘high’ groundwater potential zone encompasses an area
of 309.8 km2 accounting for 18.57 % of the total study area.
Finally, the model generated groundwater potential zones are validated with potential yield data
of various wells in the study area. The validation clearly highlights the efficiency of the
integrated RS and GIS methods employed in this study as useful modern approach for proper
groundwater resources evaluation; providing quick prospective guides for groundwater
exploration and exploitation in such volcanic rock setting.
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Keywords
Potential Groundwater Zone, Sekota Wereda, Northern Ethiopia., GIS, Remote Sensing