Abstract:
The study area, Guang river catchments, in Amhara regional state, is found in Western
Ethiopiaand can be located at UTM coordinate between (195983-203777m) E and (1438974-
1425310 m) Nwith an average elevation of 700 meters above sea level.The main objective of the
research is to assess the groundwater potential of the Guang catchment using geophysical
methods.
This integrated geophysical investigationincludes the electrical resistivity method (Vertical
Electrical Soundings/VES), magnetic methodsand Satellite gravity data).
The Schlumberger electrode configuration with maximum current electrode separation (AB) of
600m from VES-1 up to VES-5 and 1000m from VES-6 up to VES-26 was used for the
sounding survey.VES data on a total of twenty-six VES stations were collected using
Schlumberger field array along six profiles. Three to five geoelectric layers are mapped in the
geoelectric sections. The possible potential areas for groundwater production are that
characterized by low resistivity values i.e. the weathered layer and fractured zone which have
been identified as an aquifer.
The magnetic survey was conducted across Guang river to map major E-W trending subsurface
structures. From the total magnetic intensity data, the IGRF value is subtracted after the diurnal
correction was applied. IGRF corrected data were enhanced by upward continuation and analytic
signal filters to map structures that may act as a conduit for groundwater.
Satellite gravity data taken from the International Gravimetric Bureau (BGI) gravity database
was primarily aimed to map regional structures of the Guang and its surrounding catchments.
The result of the gravity reconnaissance was used to plan a detailed integrated geophysical
survey using Magnetic and electrical resistivity techniques (vertical electrical sounding).
