Abstract:
Groundwater is a critical resource, especially in arid and semi-arid regions where surface
water is scarce or unreliable. In such regions, groundwater often serves as the primary
source of water for drinking, agriculture, and industrial activities. It is the only source of
water available on the community of the study area. Therefore, considering to this a proper
assessment for identifying groundwater potential zones on the study area were required to
make suitable management and utilization of groundwater potential zones. The main
objective of this study was to delineate a map of groundwater potential zones of Hargeisa
watershed coverage using Geographical Information Systems, remote sensing and
Analytical Hierarchy Process (AHP) techniques. Seven thematic layers developed in this
research are extracted from existing maps geology, rainfall, geomorphology, soil and land
use/ land cover which derived from Operational land imager satellite and pre-processed
data which is derived from SRTM DEM used for extraction of slope and drainage density
map of the study area, prepared using ArcGIS software. In generally, all of these themes
and their individual features were given weights based on their relative importance in
groundwater occurrence, and the corresponding normalized weights were derived based
on the Saaty's analytical hierarchy process (AHP) and a standard weighted overlay
analysis were used to evaluate and generate the study's potential zones. A final thematic
map was made to identify possible places for groundwater potential zones. The created
map was classified into five zones: 'very low', 'low', 'moderate', 'high' and 'very high' of
groundwater potential area which is covered by 130 km2(1%), 8970km2(68%),
2785km2(21%), 1305km2(10%) and 6km2(<1%) respectively. Result shows, a combination
of high potential zones was found at the southwestern edge, southern and west region of the
coverage. Apart from the geology and rainfall the groundwater is closely depended on slope
of the area. Based on the results of the very high and high GWP zones are located in areas
where the slope is very flat and the poor GWP zone is located in areas where slope class is
very high. The produced groundwater potential zones are also validated using potential yield
data of 136 available boreholes and dug wells in the region and the validation revealed that
81.7 % agreed the model result. The validation clearly confirms and underlines the
efficiency of the combined RS and GIS methodologies used in this work as a valuable
current tool for accurate groundwater resource evaluation, offering timely prospective
recommendations for groundwater exploration and utilization.
