Assessment of approaches to determine the water quality status of South African catchments

[摘要] The paradigm shift in water quality management of South African water resources was basedon current international trends. This significant move was from a previous emphasis onsource management to a focus on finding a balance between water resource protection andwater use. The current approach requires that water quality and quantity should bemaintained for sustainable functioning of both the natural aquatic environment and socioeconomicdevelopment. This approach has placed the assessment of water quality status asa key decision tool in water quality management.Various assessment tools have been utilized to quantify the quality of South African waterresources. In this study we assessed the compatibility of some of the methodologies thathave been used in the Department of Water Affairs to determine and report on the waterquality status of the resource. During the assessment the context and manner in whichthese methodologies can be utilized in water quality management were also addressedThe Compliance Evaluation and Fitness for use categorization methodologies are both usedto describe the water quality threshold of potential concern when dealing with the resource.Compliance Evaluation methodology uses a pass or fail assessment, while the Fitness for use categorization methodology uses a scaled approach allowing for the assessmentof gradual change in the system. The out puts of these two methodologies, the ResourceWater Quality Objectives and Fitness for use categories/ classes have both been used in thedepartment as benchmarks to describe the current water quality statusThe assessment of the two methodologies indicated that there are similarities in theapproaches and the principles behind the two processes. The observation of the results,however, indicated differences in the manner of presentation of the results, the interpretationof the outcome and in how water quality management measures that needs to beimplemented are linked.Both methodologies are easy to apply when conducting water quality status assessments.However, the two methodologies are not sufficient on their own when making decisions onwater quality management. It was concluded that although the compliance evaluationmethodology can play a pivotal role when setting end of pipe standards, the process needsto consider the gradual changes of water quality in the river system in order to enableinstigation of different water quality management measures at appropriate levels. Further itwas recommended that with some modification the two approaches can be applied to assesswater quality to support adequate water quality management decisions at various levels.

[发布机构] University of Pretoria