The Calibration of an Artificial Stream System Used to Investigate the Tolerances of South African Riverine Invertebrates to Selected Water Quality Variables

Abstract.

Water quality management in South Africa aims at the maintenance of water in a state that is “fit for use.” This includes use for agriculture, industry, domestic supply, and recreation, together with the maintenance of the natural, functioning resource base: aquatic ecosystems. The water quality requirements of riverine ecosystems need to be established to fulfil this last aim. A first step is the investigation of the tolerances of a range of riverine organisms to key water quality variables or pollutants. However, riverine organisms require flowing water, and in order to provide a flowing water experimental facility, an artificial stream laboratory has been developed. The objective of calibrating this system was to establish the physical and chemical conditions in the streams before test organisms were introduced; then to monitor behavior of organisms in the streams before water quality conditions were experimentally altered. This paper introduces the concept of system calibration and reports on hydraulic and water quality calibration, and the effects of handling on test organisms.