A critical analysis of surface water quality in the Rietspruit Catchment, Upper Vaal Water Management Area

Abstract

Surface water quality in South Africa continues to deteriorate due to anthropogenic activities, and not enough is being done about this impending disaster. The Rietspruit Catchment in Gauteng Province, a sub-catchment of the Vaal River Catchment, is one area in which the water quality has deteriorated profoundly. The study investigated the surface water quality in the Rietspruit catchment area, which is part of the Upper Vaal Water Management Area. This was done by examining the water quality trends and comparing them to the Resource Water Quality Guidelines for the Rietspruit Catchment (RWQGRC). Existing data from 2019 to 2023 were extracted from three monitoring points in the Department of Water and Sanitation Water database and the Rand Water Reservoir database. The monitoring locations were all in-stream: upstream at Ennerdale (REN), middle catchment at Sebokeng (RV1), and downstream at Loch Vaal (RV2). The water quality variables analysed were conductivity (EC), suspended solids (SS), chemical oxygen demand (COD), ammonium (NH4 as N), nitrate (NO3 as N), sulphate (SO4), phosphate (PO4 as P), and faecal coliforms.

The water quality analysis showed that the water at Ennerdale was within the ideal and acceptable range, with sulphate levels being tolerable. The water quality in this area was not a concern, as there were very few faecal coliforms present, and the water parameters fell within the RWQGRC guidelines. Monitoring points in Sebokeng and Loch Vaal indicated unacceptable trends of faecal coliforms, phosphate, and ammonium, while chemical oxygen demand (COD) and suspended solids were within acceptable and tolerable ranges. Sulphate, nitrate, and electrical conductivity remained within the ideal and acceptable levels. The study found that water quality in the Rietspruit catchment does not meet the Resource Water Quality Guidelines for the Rietspruit Catchment (RWQGRC), posing health risks from high faecal coliform levels that could lead to waterborne diseases. The causes of poor water quality are identified as a lack of proper governance, insufficient institutional capacity, and inadequate financial management, which have resulted in minimal maintenance of aging water and sanitation infrastructure. The research recommends that all stakeholders work together to improve water quality. The Department of Water and Sanitation should enhance its enforcement of water user regulations using the waste charge-discharge system (WDCS), develop improved information management systems, and implement effective interventions.