INVESTIGATION OF GROUNDWATER POTENTIAL USING ELECTRICAL RESISTIVITY METHOD AT GARATU SECONDARY SCHOOL, NIGER STATE, NIGERIA

Abstract

Evaluation of groundwater potential was carried out at Garatu Secondary School, Garatu, Niger State Nigeria. Schlumberger electrode configuration was adopted with maximum current electrode spacing (AB/2) of 100 m. The profile separations was 100 m with inter vertical electrical soundings (VES) point spacing of 100 m from profile A to F. Total of thirty-six vertical electrical soundings station were covered. The interpretation revealed three distinctive geologic layers. The first layer which is the top layer has resistivity value ranging from 907.1 – 1605.2 Ωm, its depth and thickness varies between 1.3 – 1.8 m and 1.3 – 1.8 m respectively which corresponds to the geo-electrical parameters of fadama loam, weathered laterite and fractured basement. The second layer has resistivity value of 205.4 – 322.2 Ωm, depth of 12.0 – 17.8 m and thickness of 10.5 – 16.0 m; this layer refers to the weathered/fractured basement. The resistivity of the third layer ranged from 858.4– 4777.2 Ωm, its depth and thickness are undefined. The results clearly showed that the electrical resistivity method is suitable for and very efficient in investigating groundwater potential. The parameters (resistivity, depth and thickness) of the layers were employed to delineate the aquifer potential of the study area, their weathered/fractured layer with resistivity value varying from 148.9 to 218.9 Ωm while the depth and thickness ranged from 22.8 to 30.4 m and 21.0 to 27.3 m respectively. Five VES points C3, C4, D2, E4, and F2 were delineated as groundwater potential points of the area.