Assessing water quality of local streams and rivers is important to protect the natural environment, human health, and ensure a safe drinking water supply. When testing chemical characteristics of water, we compare them to standards set by the State of Georgia in compliance with the Clean Water Act of 1972, for water quality protection.
The Stream Monitoring Program samples 92 sites on 21 streams four times a year. By assessing water quality so frequently, a baseline of stream chemical water quality can be established. Water quality data can then be assessed to see if any parameters are elevated above the standards. If a standard is exceeded and pollution is detected, Stream Monitoring investigates to locate the source and initiate corrective action.
All samples collected by the Stream Monitoring Program are analyzed by certified laboratory analysts at the Cobb County Water Quality Laboratory. Samples collected by the Stream Monitoring Program are analyzed for the following chemical characteristics:
Biochemical Oxygen Demand Biochemical Oxygen Demand (BOD) is the measure of oxygen consumed by bacteria and other microorganisms while they decompose organic matter. |
Chemical Oxygen Demand Chemical Oxygen Demand (COD) is a measure of the amount of oxygen consumed during the chemical decomposition of organic and inorganic contaminants dissolved or suspended in water. |
Conductivity |
Dissolved Oxygen |
Fecal Coliform |
Metals Some level of metals are essential to life but high concentrations of metals are toxic to aquatic organisms. Heavy metals, which include copper (Cu), iron (Fe), cadmium (Cd), zinc (Zn), mercury (Hg), and lead (Pb), are the most toxic to aquatic organisms. Other metals analyzed are Calcium (Ca), Magnesium (Mg), Potassium (K), Sodium (Na), Boron (B), Aluminum (Al), Barium (Ba), and Manganese (Mn). |
Nutrients (Phosphorous and Nitrogen) Phosphorus is a natural element found in rocks, soil, and organic matter. Total Phosphorus is the measure of all forms of Phosphorus, dissolved or particulate, found in a sample of water. Nitrogen includes ammonia, nitrite, nitrate, organic and inorganic nitrogen. Total Kjeldahl Nitrogen (TKN) measures the sum of ammonia and organic nitrogen in the water. Nitrate dissolves easily in water and is stable over a wide range of environmental conditions. Nitrite is quickly converted to Nitrate in water by bacteria. An excess of nutrients in a water body can result in excess plant growth and eutrophication, which is the process in which decomposing organic matter depletes the water of oxygen, killing other organisms such as fish. |
pH –pH A measure of how acidic or basic water is. pH ranges from 0 – 14. Since pH can be affected by chemicals in the water, it is an important indicator of water that is changing chemically. |
Temperature Water temperature governs the type of aquatic life that can survive in the stream. Temperature also influences water chemistry, by affecting the rate of chemical reactions and biological activity, and the dissolved oxygen concentration. |
Total Suspended Solids Total Suspended Solids (TSS) are solids in water such as silt or decaying plant and animal matter that can be trapped by a filter. |
Turbidity Turbidity measures the light-scattering effect of suspended particles in the water, such as silt, sediment, organic material, and plankton. Turbidity appears as cloudiness caused by these suspended particles in the water. |