Evaluation of shallow groundwater suitability for irrigation purposes : A case study from Doornfontein area, South Africa

The present study aims at evaluating the quality of shallow groundwater (SGW) and its suitability for irrigation purpose in the most urbanised part of Johannesburg city, South Africa. The SGW samples were collected in three consecutive years and analysed for 20 selected physicochemical parameters, and heavy metals. The results were compared with the South African water quality, and Food and Agricultural Organization irrigation water quality guidelines, and standard indices derived from laboratory outputs. The results of the study show that all physiochemical parameters and heavy metals were within the limits set by both guidelines for irrigation purposes, except for potassium (3.58 mg∙dm-3) and manganese levels (3.152 mg∙dm-3). The calculated irrigation parameter values of sodium adsorption ratio (SAR), sodium percentage (Na%), residual sodium carbonate (RSC), magnesium hazard (MH), Kelly’s ratio (KR) and permeability index (PI) were within the permissible range of irrigation water quality standards. The findings of this study provide helpful information for decision-makers such as utilisation of the studied groundwater for irrigation uses.