Resumen de Hydraulic parameters evaluation of the Pan-African aquifer by applying an alternative geoelectrical approach based on vertical electrical soundings

Zakari Arétouyap, Dieudonné Bisso, Jorelle Larissa Mélii, P. Njandjock Nouck, André Njoya, Jamal Asfahani

• español

  Para este estudio se realizaron cincuenta Sondeos Eléctricos Verticales (SEVs), de los cuales en 14 sitios se tenía información de muestreos de agua. Estos sondeos se interpretaron para determinar los parámetros hidráulicos del acuífero Pan-Africano en la región de Adamawa-Camerún, y estos fueron Transmisividad (T) y Conductividad Hidráulica (K). El enfoque utilizado es efectivo y aplicable a otras áreas similares, si se toman las suposiciones adecuadas. La resistencia transversal (RT) del acuífero oscila entre 24 y 31,350 Ω.m² con un promedio de 7476 Ω.m²; la resistencia transversal modificada (RTM) oscila entre 1526 y 28209 Ω.m² con un promedio de 7873 Ω.m²; la Transmisividad (T) oscila entre 4 y 17,4 m²/día con un promedio de 7.23 m²/día y una desviación estándar de 3.42 m²/día; y la Conductividad Hidráulica (K) varía de 0,07 a 0,74 m/día con una media de 0,31 m/día y una desviación estándar de 0,17 m/día.

• English

  The present article aims at determining hydraulic parameters of the Pan-African aquifer in the region of Adamawa-Cameroon, namely the transmissivity (T) and the hydraulic conductivity (K). For this, fifty vertical electrical soundings (VESs),including 14 performed near existing boreholes with known values of water resistivity, have been conducted in the region using the Terrameter ABEMSAS-1000 with a spacing of current electrodes (AB) varying from 2 to 600 m.The curve matching technique is used to set structural parameters then, an inverse technique algorithm fits both theoretical and field curves for each experimental. The transverse resistance TR and the transmissivity T for the interpreted 14 VES are computed, then used to establish two relationships: one between the modified transverse resistance (MTR) andthe transverse resistance (TR) and another between MTR and the transmissivity (T).This enabled to compute MTR (ranged from 1526 to 28209 Ω.m² with an average of 7873 Ω.m²),TR (ranged from 24 to 31350 Ω.m² with an average of 7476 Ω.m²), T (ranged from 4 to 17.4 m²/day with an average of 7.23 m²/day) and K (ranged from 0.07 to 0.74 m/day with an average of 0.31 m/day) values in the whole region. The approach used for this purpose is effective and exportable to other Pan-African regions in the world.