| dc.description.abstract | The Klip River wetland is one of the most economically important ecological river system in South Africa as it plays two roles: water purification in the Vaal River system and is also a source of water. However, several studies have demonstrated that the wetland is extremely degraded and has lost capability to perform the two function s. As a large catchment river system, the Klip River runs through different land uses and is subsequently prone to high water quality variability along its course and over time. The main aim of this research was to determine the spatial and temporal mechanisms influencing water quality, sources of pollution
and the associated risks in the Klip River catchment. Thus informing the process of developing a framework for the monitoring and management of water quality in the catchment. The methodology was centered on data collected from water quality monitoring activities from February 20 I 6 to January 2017. Water samples were collected along the profile of the Klip River and analyzed for Al, As, Ca, Cd, Co, Cu, Cd, Fe, K, Mg, Mn, Na, Ni, Pb, U, V and Zn using Inductively Coupled Plasma-Mass Spectrometry (ICP-MS), and nitrates and phosphates
using Spectrophotometry. Water quality results were compared against South African water quality guidelines (SA WQG) for aquatic ecosystem protection, agricultural and domestic uses. To assess the seasonal and spatial dynamics of the water quality, multivariate statistics were employed. Furthermore, to classify seasonality and spatial level of pollution in the catchment, various environmental indices were computed; there included heavy metal pollution index, Potential ecological risk index, Comprehensive Pollution Index. In addition, analysis into the river's ability to self-purify was conducted using River Recovery Capacity and Capacity for self-purification per unit length calculations. Findings revealed that the Klip River water quality is not in compliance with the SA WQG for aquatic ecosystem protection, agricultural and domestic uses thereby rendering the water unsuitable for its designated uses. Consequently, water quality in the Klip River Catchment (KRC) poses significant ecological and health risks. Furthermore, water quality in the Klip is influenced by spatial and seasonal factors. As such the KRC was grouped into two homogenous water quality zones, i.e. the upstream and downstream zones, and this was attributed to the influence of land use activities. Furthermore water quality in the KRC displayed homogenous characteristics in the 2015/16 season comprising of the period from February to June, and 2016/17 season comprising of the months from July to January. This was attributed to the effects of El Nino Southern Oscillation (ENSO) and La Nina phenomena phenomena respectively. Critical pollution was recorded in the upstream zone, in the 2015/16 season relative to the downstream and the 2016/17 season respectively. This was attributed to the evaporation and consequently low volume of water in the river. The main sources of pollution in the KRC included lithological, traffic, mining, point discharges from industries and sewage effluents. These sources varied between seasons and spatial locations. It was also observed that the Klip River possesses a natural capability even though limited, to self-purify for some heavy metals (Cd, Cr, Mn, Ni and Zn). A surface water quality management plan was developed which highlighted the most impaired designated water uses and overall priority pollutants in the KRC. The management plan was used to identify appropriate water quality management measures specific to the KRC. Furthermore a framework for monitoring and evaluation of water quality was developed which outlines the pollutants to monitor per site and the specific uses for which to monitor. Findings from this research demonstrated the adeptness of applying multivariate statistics in dimension reduction, understanding of complex water quality monitoring data and identification of pollution sources in the Klip River Catchment. In addition, findings from this study serve as a guideline for developing strategies for monitoring, evaluating and managing surface water quality in other catchments. These findings can also be used to inform policy makers and various stakeholders to enable the design of efficient mechanisms for water quality management. | en_US |
