GROUNDWATER VULNERALITY ASSESSMENT USING ELECTRICAL RESISTIVITY METHOD IN PARTS OF OMUMA AND OYIBO LOCAL GOVERNMENT AREAS, RIVERS STATE

Abstract

Seven Vertical Electrical Soundings were  carried out.  The study involved the use of  schlumberger  configuration. The thrust  of this  work  is  on  determining the  vulnerability  of the  hydrogeological  units  by  employing the  use of  electrical  resistivity  method  to  evaluate  the  vulnerability  of  aquifers  to  contamination in parts of  Omuma and Oyibo Local  Government  Area, Rivers State, Nigeria.  The  resistivity  data  measured  were  interpreted  manually  and  with  resist  computer  software  packages, which  gave the  resistivity, depth and  thickness for  each layer  within the  maximum  current  electrode   separation.  Isopach  map  showing the  depth of the  aquifers and  the  longitudinal  conductance  estimating the  aquifer  protecting  capacity were obtained.  The  longitudinal  conductance  ranges  from 0.005  to   0.13 mhos.  The  study area  is  vulnerable  to  contamination. The  isopach  map shows  a  variation  in the aquifer  thickness  from  20 to  105m.  The  region  with  high thickness  variation of  50 to  105m falls  within the  North  and  the  central region.  This  coincide with  prolific  aquifers.