The relationship between the infrastructure, within the palmiet catchment, and the condition of the Palmiet River water quality and Riparian zone.

Abstract

The construction and daily operation of infrastructure systems, has imposed significant negative consequences on the natural environment. The primary aim of this study was to explore the relationship between the infrastructure, within the Palmiet Catchment, and the condition of the river water quality and riparian zone. It was hypothesized that the Palmiet Catchment has been significantly impacted by the development of the surrounding land. Visual observations of the accessible areas of the Palmiet River, and its associated tributaries, were undertaken with the following key impacts assessed: indigenous vegetation removal, exotic vegetation, channel modification, inundation, water abstraction, flow modification, bed modification, water quality and rubbish dumping. The recorded impacts were then represented onto Geographic Information Systems forming baseline maps of the current ecological condition of the Palmiet River, relative to the abovementioned impacts. Results indicated that the Palmiet River and its riparian zone were in various degrees of degradation. The river channel has been extensively modified by hard infrastructure, thus reducing the infiltration ability resulting in the channelling of the river water. In addition, the impervious surfaces, numerous stormwater outlets and obstructions, i.e. infrastructure supports within the river channel, has significantly modified the flow rate causing the scouring of both the riverbed and riverbank. Numerous blockages and failures in the sewer system as well as illegal activities of industries, in the Pinetown and New Germany areas, has resulted in sewage, containing trade effluent, being discharged directly into the Palmiet River, affecting the water quality. The informal settlements, located near the mouth of the Palmiet River, are another major contributor to the degradation of the Palmiet catchment. Service delivery problems and trust issues in this area has resulted in the accumulation of waste items along the riverbank. The results obtained validate the hypothesis that urbanisation, and infrastructure development in particular, has led to the degradation of the natural environment. By understanding the extent and severity of the impacts imposed on the Palmiet Catchment remedial interventions can be implemented. These interventions include: retention ponds, weirs and wetlands to regulate and slow down the flow of the Palmiet River; geotextile engineering solutions as opposed to hard infrastructure solutions to stabilise collapsing riverbanks; rainwater tanks and retention areas in industries and households to reduce the amount of runoff entering the Palmiet River, the rainwater tanks can potentially also serve as a supplement to the water needs, thereby, reducing the water bills; improved service delivery and the potential hiring of members from the informal settlement to reduce and remove the accumulation of waste and promote trust between different members of the community, and wider municipal area.