RMZ – MATERIALI IN GEOOKOLJE

∆V=∫E.dr.Iρ∆V=2πrThe groundwater potential evaluation at industrial estate Ogbomoso, ...377to ρ = bedrock, ∆V.2πrweights that are directlyproportional to the overburden thicknesshave ∆Vbeen assigned (Olayinka etρa= . Gal., 1997). I These weights range from aminimum of 2.5 for thickness less than5 m to a AB maximum 2 MNof 2π (( ) − ( ) 10 ) for overburdenG = thickness 2 exceeding 2 15 m (table 3).MN2( )Coefficient of Anisotropy 2 of the OverburdenThe ρ1> overburden’s ρ2< ρ3coefficient of anisotropy(λ) was calculated for each VES stationρusing the layer resistivities and thicknesses(Olorunfemi & Okhue,1< ρ2> ρ3< ρ41992);λn−1∑h ρn−1∑i iρti=1 i=1= =n−1ρl2(∑ hi)i=1hiρi(9)where ρ tis the transverse resistance,ρ lis the longitudinal resistance, i isthe summation limit varying from 1to n – 1, h iis the ith layer thicknessand ρ iis the i-th layer resistivity.The λ values were plotted and contoured.This was done in order to knowthe areas that are good for groundwaterprospects. Areas which show ridgeson the map will be promising zonesfor groundwater prospects while areaswhich show depressions on the mapwill not be suitable for groundwaterprospects. The resulting overburdencoefficient of anisotropy map (figure5) shows λ values ranging from 1.0 to1.45 with a mean value of 1.16. Vividly,the Northeastern and to the baseKT = × R = Kσ×ρTR TFigure 5. Overburden anisotropy coefficient map.RMZ-M&G 2012, 59