ABSTRACT
The inhabitants
of this area depend solely on contact springs as supply source of potable
water. However, provision of potable water to meet the needs of the people
still remains an unsolved problem. Therefore, this paper attempts to solve this
problem by using Dar Zarrouk (D-Z) Parameters; Total Transverse Unit
Resistance, T (Ωm2) and
Total Longitudinal Unit Conductance, S (Ω-1) to suggest optimal locations for drilling of boreholes in the
study area. To attain this purpose, 50 Schlumberger Vertical Electrical
Sounding (VES) curves with maximum current electrode spacing of AB/2 = 681 m were interpreted. Thus, the
aquifer parameters information estimated from the (VES) curves were used to
prepare contour maps of T (Ωm2), S (Ω-1), aquifer thickness h (m), aquifer resistivity ρ (Ωm), and Water Table Depth (WTD). For effective use of these parameters,
iso-thickness and iso-resistivity maps were compared with contour map of
transverse resistance. The good agreement between these parameters provided the
basis for identification of prolific aquiferous zones. It was observed that the
Southern part of the study area majorly underlain by the Afikpo Sandstone of
Nkporo Formation (Campanian-Maastrichtian), relatively showed higher T (Ωm2), h (m), and ρ (Ωm) values,
which implies high yield aquiferous zones. The relatively loose structure of
this sandstone unit, coarse grains, and sorting enables it to be porous and
permeable. The Northern part of the region which shows low values for T (Ωm2), h (m), and ρ (Ωm)
suggests low productivity for the aquiferous zones. The paucity of water in
this parts of the study area can be explained to be as a result of the dominant
geology. The high S, values at the
Uburu and Okposi locations in this region suggests the presence of saline
aquifer. This study would be relevant to the development of effective ground
water scheme and for future hydrogeological investigations in the area.