Progrès de la recherche en sciences appliquées Libre accès

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Evaluation of ground water resource in Akamkpa area, Cross river state, Nigeria

Theophilus O. Arong, Avwenagha E. Oghenero

A combined analysis of lineament length and density from radar imagery and surface resistivity data were used to assess the hydrogeologic conditions in Akamkpa Area, Cross River State. Twenty vertical electrical soundings (VES) were carried out in the area using maximum current electrode spacing of 600m (AB/2=300M), employing schlumberger electrode configuration. The data were interpreted using conventional partial curve-matching method to obtained initial parameters, which were used in a computer programme (REX 2 DINV) to obtain final parameters. The interpretation showed a geological setting with three to six Geoelectric layers occurring more in the area. The first layer has apparent resistivity range of 53.2Ωm-4492.4Ωm, the second layer has apparent resistivity range between 63.3Ωm-8389.9Ωm. The third layer has apparent resistivity values of 406.0Ωm- 3623.0Ωm, the fourth layer has apparent resistivity values between 42.5Ωm-6969.0Ωm, and the fifth layer has resistivity range of 75.0Ωm-34999.0Ωm. The result shows that the second, third, and fourth Geoelectric layers constitute the aquiferous unit depending on location in the area. Correlation of the sounding curves with Lithologic data from nearby borehole showed that the major Lithologic units penetrates weathered laterite, shallow saturated layer of weathered basement, and a fresh basement. Interpretations of radar imagery were done by identifying the lineaments, their number, total length, and total area. This revealed that the area is intensely fractured. The fractures trending in the N-S, NE-SW, and NW-SE directions. The total lineament length of the area is calculated to be 3010.10Km with the frequency of the lineament decreasing in the southwest direction

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