Groundwater quality assessment of a freshwater wetland in the Selangor (Malaysia) using electrical resistivity and chemical analysis

Abstract

Groundwater quality of the Paya Indah Wetland (PIW) was targeted for the present study using integrated two-dimensional electrical resistivity imaging (ERI) and hydrochemical surveys. Electrical resistivity and the influence of variations in the lake level were investigated using daily water balance measurements, water sampling and geochemical analysis, and well-logging. The geoelectrical resistivity surveys comprised 14 resistivity traverses in the PIW. The resistivity surveys predicted the high-permeability areas separated in order to provide pathways for lake drainage. The resistivity inverse model showed that the freshwater zone is extremely clear. Chemical analyses of the groundwater samples obtained from seven boreholes from 2010 to 2013 were studied. The total dissolved solids and electrical conductivity were represented as being less than 500 mg/L and 600 μmhos/cm, respectively, and freshwater was therefore indicated. The lake water level was proportionate to rainfall fluctuation with the level measured in 2010. The soil and groundwater confirmed there to be fresh and brackish water zones in the study area, this result being obtained from ERI and the hydrochemistry of the groundwater samples.