1. INTRODUCTIONClean, fresh water is essential for all life forms on earth. Humans use water daily for domestic, industrial, agricultural and other uses. Our economic and social well-being therefore depends on the availability of clean water resources and efficient river systems. In South Africa, it is particularly important to monitor and conserve our water resources, due to the low amount of rainfall received and the country's classification as water-stressed. However, the quality, quantity and range of services provided by rivers can decline when river health is compromised. In an effort to maintain the good condition of our rivers, wastewater plants clean and purify sewage for release into the river system once it meets the cleanliness requirements specified in regulations set by the South African Department of Water Affairs. Proper wastewater treatment is important to ensure that receiving rivers into which wastewater is discharged are not further polluted. Our rivers have the capacity to cope with small amounts of pollution (assimilative capacity). However, they would be overwhelmed if the millions of liters of wastewater South Africans produce every day were not first treated before being discharged back into rivers. If wastewater is not treated properly, negative impacts on human health and the environment may be observed downstream of wastewater discharge. These impacts include harm to wildlife populations (particularly fish and invertebrates that live in the water), disease in people who use the river for recreational purposes (swimming and canoeing), and even contamination of drinking water sources. Pollutants are commonly found… in the middle of the paper… in summary, the review of these literature sources indicated that inadequately treated wastewater can have a detrimental impact on the health of the river and the downstream environment. When the receiving river is of poor quality upstream of the effluent discharge, minimal impacts are often observed downstream of the effluent discharge, but larger impacts are seen when the receiving river is in pristine condition. Biomonitoring is considered an effective technique for assessing these impacts as it provides a holistic and integrated measure of river health that can be used to improve community participation and management of our river systems.3. HYPOTHESIS The hypothesis for this research assignment is: Effluent released from the Howick Wastewater Works has a greater detrimental effect on the downstream aquatic environment than the Darvill Wastewater Works.