Abstract:
Groundwater is one of the water resources which plays an important role in water supply in
many countries including Ethiopia. Identifying and delineating the groundwater potential
zones is very important for development plans, policies and sustainable utilization of the
groundwater resources in the area of interest. However, there were only limited studies
conducted on groundwater potential of the Megech watershed. This study is mainly aimed to
identify and map the groundwater potential zones of Megech watershed. A total of nine
thematic layers including geology, lineament density, slope, geomorphology, soil, LULC,
rainfall, drainage density and elevation were used to map the groundwater potential zones of
Megech watershed in GIS environment. Weights and rates were assigned for each thematic
layer and for each thematic layer classes respectively using the PriEsT AHP tool. ArcGIS
overlay analysis was conducted to obtain the groundwater potential map. The percentage of
influence to the output map of the study area in view of groundwater potential was computed
using PriEsT software package having geology/lithology 30%, lineament density 23%, slope
15%, geomorphology 10%, soil 7%, LULC 6%, rainfall 4%, drainage density 3% and finally
elevation 2%. The first four thematic layers (geology, lineament density, slope and
geomorphology) were found to be the dominant factors as portrayed in the map removal
analysis. There were three groundwater potential zones identified and mapped in the study
area namely low, moderate and high. The qualitative results were also compared with an
independent set of 79 groundwater point data to validate the results. The validation analysis
showed 75% agreement between the groundwater point data classes and the groundwater
potential zones identified.
