Sustainable management and characterization of groundwater resource in coastal aquifer of Niger delta basin Nigeria

A study was conducted in a coastal region of Port Harcourt, Niger Delta, Nigeria, to identify the hydrogeochemical processes influencing groundwater chemistry. The major geological units of the study area are sand, silt and shale of Oligocene–Pleistocene of Benin Formation. For the purpose of this study, a total of 18 groundwater samples were measured for major ions. Findings from this showed that areas underlined by high electrical conductivity values indicate areas with poor groundwater quality. Results from hydrogeochemical facies analysis plotted in Piper diagram showed a trend of Na⁺ + K⁺ > Mg²⁺ > Ca²⁺ > Cl⁻ > SO₄²¯ > HCO₃¯. Further findings from hydrogeochemical analysis revealed that groundwater is of the same origin, deductions from Chadba plot revealed that saline water intrusion influenced hydrochemical composition of groundwater it was reflected by Na–Cl type waters. Results from Gibbs plot revealed that precipitation is major hydrochemical process that influence groundwater, salt water intrusion may also be connected to anthropogenic impacts; such as sewage disposal from septic tanks. In summary, abstraction of groundwater in the area should be reduced, spetic tanks should be built far from where borehole are sunk. Finally government should ensured water purification plant are installed while drilling borehole, to further reduce the current level of salinity in groundwater. Moreso, good hygiene and good sanitary habit should be inculcated by the inhabitant of the study area.