The relationship between the infrastructure, within the palmiet catchment, and the condition of the Palmiet River water quality and Riparian zone.
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Date
2016
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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.
Description
Master of Science in Civil Engineering. University of KwaZulu-Natal, Durban 2017.