Satilla Riverkeeper and a team of dedicated volunteers conduct water quality sampling at 10 public landings on the Satilla River Water Trail. During the summer months, water quality samples are taken every two weeks. The most recent testing took place on Wednesday, September 16.
One of the parameters volunteers test is bacteria. The concentration of Escherichia coli (E. coli), a species of coliform bacteria found in the gastrointestinal tract and feces of mammals, can be an indicator of the presence of other harmful bacteria or pathogens in the water. All of the public landings tested on Wednesday, September 16, 2020 showed E. coli levels within the safe limits for swimming areas.
After a significant amount of rain this past week, the Satilla River rose several feet. At the USGS gauge near Waycross, the river crested just below 11 feet on Saturday, September 19. According to the USGS data, the Satilla River near Atkinson crested at 8.5 feet on Monday, September 21 and still rising.
Site Bacteria Count. (cfu/100mL)
Jamestown Landing 33
Hwy 121 Nahunta 0
Us 84 Waycross 66
FFA Camp Landing 33
US 301 Nahunta 0
US 82 Ava Lightsey Strickland Landing 166
Warner’s Landing 133
Woodbine Waterfront Park 33
Why look specifically for E. coli?
E. coli acts as an indicator species. If significant amounts of E. coli are found, there are most likely other bacteria such as disease-causing bacteria and viruses. However, this is not always the case. Just because there are colonies of E. coli found in the water does not mean that there are always the other harmful bacteria and viruses present. And vice versa, just because E. coli isn’t detected, it does not mean that the water ways are always safe. There is, however, a proven positive correlation with high levels of E. coli and illness and infection.
How does E. coli enter our waterways?
E. coli may enter our water ways through a variety of pathways. Agricultural runoff is a large contributor of E. coli into streams and rivers. Old and worn septic systems are another major player in E. coli introduction as they are likely to leak into the environment and ultimately into waterways. The last major contributor is through legacy bacteria. This is bacteria that has managed to remain in an area long after the site where it was created has been abandoned. During rain events, this bacteria is churned up into the water column with soil and manages to find its way into the water way.
The Satilla Riverkeeper has run a five-week project, sampling sites along the Satilla River once a week for the duration of the five weeks. One day of each week has been used to sample and the following day has been used to read the results. The water samples were incubated for 24 hours. Even weekly sampling results may not always be accurate. Rain events immediately following sampling may lead to temporarily spiked levels of E. coli that could not be accounted for.
All results of bacteria testing from the Satilla Riverkeeper are posted to Swim Guide. However, it is best to make decisions with one’s own judgement. If there has been a recent storm, chances are there are going to be higher levels of E. coli. If it has been a dry week, E. coli levels are probably low. By pairing the data found on Swim Guide with personal judgement based on these factors, one can ensure a safer trip to the Satilla River.
The Environmental Protection Agency recommendations for E. coli levels in recreational waters are in the table below:
|
Designated swimming |
Moderate swimming area |
Light swimming area |
Infrequent swimming area |
|
|
E. coli (cfu/100ml) |
<235 |
<298 |
<410 |
<576 |
In addition to monitoring bacteria levels, volunteers use the protocols developed by Georgia Adopt-A-Stream to monitor dissolved oxygen, pH, temperature, and conductivity. These water quality parameters serve to provide an early warning to the potential of nonpoint source contaminants in the Satilla River. Volunteers sample sites along the Satilla River on a monthly basis and report the data to Adopt-A-Stream (https://adoptastream.georgia.gov ).
If you are interested in becoming a water quality monitoring volunteer, please contact Trish DuBose, waterquality@satillariverkeeper.org.