RMZ – MATERIALI IN GEOOKOLJE

The groundwater potential evaluation at industrial estate Ogbomoso, ...383ear relationship between groundwaterpotential and the transverse resistanceof an aquifer (Aderinto, 1986). Table6 gives a summary of the variation ofaquifer potential with transverse resistance.Bedrock Relief MapThe bedrock relief map (figure 9) isa contoured map of the bedrock elevationsbeneath all the VES stations.These bedrock elevations were obtainedby subtracting the overburdenthicknesses from the surface elevationsat the VES stations. The bedrockrelief map generated for the locationsshows the subsurface topography ofthe bedrock across the surveyed area.Bedrock relief map helps to see vividlythe suspected areas for groundwaterprospects. Areas with basementdepressions on the map serve as collectingtrough for groundwater whichwill be the best zones for groundwaterprospects. Bedrock relief has beenused by Okhue & Olorunfemi (1991),Olorunfemi & Okhue (1992), Dan–Hassan & Olorunfemi (1999), Olorunfemiet al, (1999) and Bala & Ike(2001) to investigate into groundwaterprospects at Ile- Ife SW, KadunaNorth Central, Akure SW and GusauNW part of Nigeria respectively.Procedures used by them have beenadopted under this subsection in orderto get the promising areas for groundwaterprospects at Industrial EstateOgbomoso SW Nigeria.The map shows series of basementlows/depressions and basementhighs/ridges. Southern, Eastern andNortheastern part (i. e. VES 2, 6, 8and 9) are the designated areas forthe depressions while Northwestern,Western, Southwestern and Southeasternpart (i. e. VES 1, 3, 4, 5 and7) are ridges zones. The depressionzones are noted for thick overburdencover while the basement high/ridgezones are noted for thin overburdencover. Omosuyi & Enikanselu (1999)findings revealed that depressionszone in the basement terrain servesas groundwater collecting troughespecially water dispersed from thebedrock crests. Thus, the zones withbasement depressions are priority areasfor groundwater development inthe study locations.If the bedrock has a low resistivity,a high aquifer potential could beinferred as result of expected highfracture permeability. Bedrock resistivitiesof the study area from figure3a–b are as given below: VES1 = 95835.0 Ω m, VES 2 = 606.4 Ωm, VES 3 = 2160.8 Ω m, VES 4 =4580.4 Ω m, VES 5 = 1830.7 Ω m,VES 6 = 271.8 Ω m, VES 7 = 4344.4Ω m, VES 8 = 14522.8 Ω m, VES 9= 6781.7 Ω m and VES 10 = 4036.2Ω m. The maximum weight of 10 istherefore assigned to cases wherethe resistivity of the bedrock is lessthan 750 Ω m. As the resistivity ofRMZ-M&G 2012, 59