A number of the Friends of Peachtree Hills Park have been certified by Georgia Adopt-A-Stream (AAS), part of the Watershed Protection Branch of the Georgia Environmental Protection Division, to monitor the health of the section of Peachtree Creek that runs through our park. Jeff Kirsch and Ron Loines are currently our resident certified “creek geeks” conducting chemical, bacterial, and visual monitoring and reporting the results on the Georgia Adopt-A-Stream web site.
You’re invited to visit the web site to see the results of our monitoring and learn about the health of our creek and watershed. Our part of Peachtree Creek is in the Upper Chattahoochie watershed and is identified with site ID 2033. This brief guide is intended to give you a sense of how to interpret the information we post on the AAS site. But feel free to chat with Jeff or Ron anytime with questions or concerns about the health of our creek.
Chemical monitoring involves testing temperature (air and water), conductivity, pH, and dissolved oxygen. Similar to results of lab tests in people, measurements that are way out of normal range are reported for immediate action. Otherwise it’s generally more useful to look at trends over a period of several months to take early action before a big problem arises.
|Measurement||Normal for our area||What the results mean|
|Temperature (air and water)||N/A||Rise in water temperature could mean “thermal” pollution|
|pH||6-8 is considered normal. Our creek generally hovers between 6.5 and 7.0||By definition, it’s a measure of hydrogen ions, but most people think of pH as how acidic (low pH) or alkaline (high pH) something is. pH is measured on a 14-point scale where 7 would be considered neutral. Distilled water, for example, has a pH of 7.0|
|Conductivity||Typically 50-1500 with ours usually between 200 to 260||Conductivity measures the presence of ions or the number of dissolved inorganic compounds (also known as salts). There is no overall norm for our area as conductivity is affected foremost by geology. Limestone and clay increase conductivity while higher concentrations of granite lower conductivity.|
|Dissolved Oxygen||Average of 5 milligrams/liter||Dissolved oxygen, or DO2, is a good indicator of a stream’s ability to support aquatic life. Things that increase dissolved oxygen include plant materials, barometric pressure and turbulence. Decreases in DO2 may be due to warmer temperatures, slow, still, or deep water, or an overload of decaying material.|
What we look for is the presence of E. coli, a fecal coliform (colony-forming) bacteria that lives peacefully and harmlessly in the intestines of us warm blooded mammals. Any E. coli that might be discovered in our creek is directly attributed to the waste of animals. So things like sewage spills, failing septic systems, leaky pipes, storm run-off, and so forth cause an increase in the levels of E. coli in a water way.
E. coli is measured in terms of colony forming units (CFU) per 100 milliliters of water. Ordinarily E. coli is harmless but poses a human (and pet) risk at excessive levels. Counts equal to or greater than 1000 cfu/100 ml warrant immediate action and have to be reported immediately to Watershed Management.
The table below shows the recommended E. coli standards for recreational waters. The levels shown correspond to an acceptable risk level of 8 people out of 1000 getting sick.
|Designated swimming area||Moderate swimming area||Light swimming area||Infrequent swimming area|
|E coli (cfu/100ml)||<235||<298||<410||<576|
In addition to our chemical and bacterial monitoring, we also report changes in the overall appearance and characteristics of the creek and the creek bank. Visual inspection includes things like clarity or turbidity of the water, excess amounts of silt or organic matter, erosion or damage to the creek banks, and so forth.