Hydro- Geoelectrical Investigation of Mubi and Its Environs in Adamawa State

Abstract

Mubi and its environs falls within latitude 10° 12¹N and 10° 20¹N and longitude 13° 10¹ E and 13° 20¹ E, an area expanse of about 78.75km2 .Thirty (30) water samples were collected from various hand- dug wells, boreholes, streams and rivers in the study area and some lithology profiles were also collected from Adamawa State Agricultural Development Program me responsible in providing water for both Urban and Rural areas within the State. All the samples were hydro geochemically analyzed and the results revealed that most of the samples’ physical parameters (pH, EC, TH, TDS) are within permissible range of World Health Organization (WHO) Standard for drinking water, domestic and Agricultural purposes except for few cases (samples at Lokuwa, Wuro- patuji, Police Barracks and Kofar Sarki) that have values exceeding the permissible limit. The results of the chemical analysis of the cat ions revealed that K2+, Ca2+, Mg2+ have values within permissible limit by (WHO) for drinking water and domestic use. Sodium (Na2+) concentration in samples from the study area was found to exceed the maximum permissible limit of 200mɡ/L except for samples from Barama and Digil that have values within the maximum permissible limit. The results of the anions revealed that Cl-, So42-, Po43-, Co32-, No3- in samples from the study area have values within the permissible limit according to WHO with exception of HCo3- that had value exceeding the permissible limit from hand-dug well at Digil. Seventeen (17) vertical electrical soundings (VES) of maximum electrode separation of AB = 320m (i.e. AB/2 = 160m) were carried out in the study area near most of the hand–dug wells, boreholes, rivers and streams where water samples were earlier collected. v The curves in the area revealed 3-4 layers and they are mostly KAH type curves. The first layer is top soil (loosed sand) with mean thickness of 0.9m and average resistivity value of 136.6Ωm. The second layer is flow top basalt with mean thickness of 0.8m and average resistivity value of 12533Ωm.The third layer is weathered /fractured basement and has a mean thickness of 3.2m and average resistivity value of 1,773Ωm. The fourth layer is a layer of fresh bedrock with a mean thickness of 7.6m and average resistivity value of 11,615Ωm. The aquifer thickness ranges from1.3 – 22.1m and the depth to water table also ranges from 1.3– 33.5m. Hydraulic conductivity and Transmissivity of aquifers in the study area were computed and found to have values ranging between 2.0 – 66.4m/day for K and 6.1 – 377.8m2/day for T respectively. The results of the VES were computed and then correlated with the hydro geochemical results. The hydro geochemical results were also compared with World Health Organization (WHO) Standard values. The overall hydro geochemical results revealed that the ground water in the study area is good for drinking, domestic and agricultural purposes. From the study, Digil, Arahan-kunu, Festac Hotel Yelwa, Federal Polytechnic Mubi and Kulb Bible school have been found as suitable areas of good ground water potential for citing boreholes to be used for water supply for drinking water and domestic purposes.