Estimation of the fate of microbial water quality contaminants in a South African river

Abstract

The aim of this study was to evaluate the validity of assumptions, regarding assimilative capacity for microbial contaminants, implicit in microbial water quality management in South Africa. A one dimensional steady state stream water quality model, assuming first order decay of microbial water quality variables, was employed in an attempt to describe and predict microbial water quality in the chosen catchment. Based on the faecal coliform counts the results indicated that the processes of decay and dilution were inadequate to yield water quality which complied with South African and international guidelines for the domestic and recreational use of water. It was also found that a first order decay model can, with fairly limited data, allow a manager to investigate different microbial water quality scenarios in a cost-effective manner.