Evaluation of the role of SASS4, as an aquatic biomonitoring method, in the ecological risk assessment process and in the determination of resource directed measures for the Luvuvhu River

The focus of the National Water Act (Act 36 of 1998) is on the sustainable utilization of our water resources. This is to be achieved through the implementation of an integrated resource protection approach, which is aimed at ensuring that a balance is maintained between the protection and utilization of our countries water resources. This approach sets Resource Quality Objectives (RQOs) that define acceptable levels of water resource protection. The acceptable risk of damage to the ecological integrity of a water resource will play an important role in the setting of these objectives, e.g. for a water resource of lower importance a higher risk would be acceptable with the subsequent setting of RQOs at less stringent levels. A desktop Resource Directed Measures (RDM) determination has already been performed for the Luvuvhu River in the Northern Province. There was decided to evaluate a facet of this desktop study, namely the Present Ecological Status (PES), by utilising the South African Scoring System version 4 (SASS4) and the Integrated Habitat Assessment Method (IHAS) biomonitoring techniques. It was then possible to compare the desktop determined PES to the PES determined from the information provided by the biomonitoring techniques. Ultimately, SASS4 verified the reliability of the RDM methodology Further, to facilitate the introduction of Ecological Risk Assessment (ERA) into South Africa there was looked at how and where SASS4 and IHAS would fit into the various phases of the ERA process. SASS4 serves as an indication of the extent of an impact, and in conjunction with an ERA, would provide the means with which to determine causality. A retrospective ERA based on data obtained from SASS4 and a concomitant habitat assessment method will thus provide a valuable tool for the protection of our water resources.Prof. G.J. Stey