Water quality is a term used to describe the chemical, physical, and biological characteristics of water, generally in terms of suitability for a particular or designated use. The designated use of the South River is fishing. Monitoring data from three important parameters are used to assess water quality. Chemical factors are a measure of substances such as nutrients (e.g., fertilizers), heavy metals (e.g., zinc, copper), and pesticides. Physical characteristics of water quality include but are not limited to temperature, dissolved oxygen, and suspended solids. Biological parameters refer to aspects of the living environment from microscopic algae and invertebrates to fish. Changes in these three parameters, over time, can tell us a lot about the health of the South River and can alert us to pollution issues that need to be addressed.
The South River’s water quality pendulum has shifted from very bad to significantly improved, with much of the improvement coming in the last 10 to 15 years. Today, the greatest threat to the river’s water quality is stormwater runoff followed by combined sewer overflows (CSOs - Atlanta), and sanitary sewer overflows (SSOs - DeKalb County). Atlanta has greatly reduced its CSOs over the past decade and DeKalb must eliminate its SSOs by 2020. The South River’s water quality revival confirms that when sources of pollution are addressed, water quality can improve relatively quickly.