FoRR took to the river on August 15 and 17 to monitor five sites in the Reedy River watershed. Reedy River at Unity Park was monitored on August 15 and all other sites were monitored on August 17.

FoRR’s monthly sites include: 

• Site #1: Reedy River just downstream of Swamp Rabbit Café 
• Site #2: Reedy River at Unity Park Auro Bridge
• Site #3: A small tributary of the Reedy River in Falls Park 
• Site #4: Reedy River in Cleveland Park near confluence of Richland Creek and Reedy River
• Site #5: Reedy River on Mauldin Road upstream of ReWa's headquarters

The pH results at all sites decreased slightly from last month’s sampling event. This indicates slightly more acidic conditions this month, but all results still fell within the state standard range of 6 to 8.5.

August’s air and water temperatures averaged 28.8°C and 25.1°C, respectively. Air temperatures ranged from 26-31°C (about 79 - 88°F) and water temperatures ranged from 23.5-26°C (about 74 - 79°F). The air temperatures increased at all sites this month except for Unity Park which decreased by 3 degrees, likely due to sampling during a cold front just before a major storm system came through. The water temperatures at all sites varied only slightly from July’s results.

The E. coli bacteria results for August showed significant increases at the Swamp Rabbit Café, Cleveland Park, and Mauldin Rd. sites, while the level at Unity Park showed no change from last month (233 CFU/100mL) and the Falls Park levels dropped from 667 CFU/100mL to 433 CFU/100mL. We noted 0.92” inches of rainfall within the 24 hours prior to sampling, which is most likely the cause of the elevated results at most sites. Heavy rains like those experienced in our watershed on August 16-17 can result in elevated E. coli levels due to the stormwater runoff produced by the storm and the higher, faster water levels in the river, which can mix up sediment from the bottom of the riverbed that would typically sequester some of the E. coli present in most tributaries. When the sediment is disturbed by heavy stream flow after major rain events, that bacteria that is being stored by the sediments is reintroduced into the water and then picked up by our monitoring team when we gather a bacteria sample. While the levels at both Cleveland Park (1,000 CFU/100mL) and Mauldin Road (1,067 CFU/100mL) met or exceeded the “problematic” threshold of 1,000 CFU/100mL set by the SC State Standards, we recognize the distinct correlation between the rain and likelihood of increased bacterial presence when sampling in these conditions. As such, we believe the high E. coli levels are a result of the rain and not the result of any sort of ongoing issue.

August’s dissolved oxygen (DO) results ranged from 5.1 mg/L at Mauldin Rd. to 7.1 mg/L at Unity Park. All sites except for Unity Park demonstrated lowered DO levels compared to last month and were within a range of 5.1-5.7 mg/L. Unity Park’s outlier result goes hand-in-hand with the air and water temperatures at Unity Park both decreasing while all other sites’ air and water temperatures increased this month. Colder water has a higher capacity to hold more dissolved oxygen, so this is likely why we’re seeing Unity Park’s results differ from the patterns at other sites this month. Unity Park was also sampled right before a large rainstorm, whereas Swamp Rabbit Café, Falls Park, Cleveland Park, and Mauldin Road were sampled immediately after the multi-day rainstorm. The warmer water temperatures and increased turbidity following heavy summer rains can both impact DO levels and are likely the cause of lower DO levels at sites sampled after 0.92” of rain in the 24 hours prior to sampling. Even with the significant decreases when compared to last month, the DO levels at all sites still exceeded the state average of 5 that is set by the SC Adopt-a-Stream program.

August’s turbidity levels all increased or, in the case of Unity Park, stayed the same this month. The turbidity levels at the sites sampled on 8/17 after significant rainfall all had elevated turbidity levels compared to the normal levels at these sites (usually around 5-7 NTUs), but this is not cause for concern this month since we know that the increased turbidity was simply a result of heavy rainfalls and the stormwater runoff rains produce in the Reedy watershed, which can introduce new sediment to the waters and stir up the riverbed sediments, resulting in increased turbidity (or cloudiness of the water). We believe the high turbidity levels this month are a result of the recent rain and not due to an ongoing issue. We hope to be able to sample under more ideal conditions next month and see levels return to normal. If you’re interested in learning more about how you can help reduce high turbidity levels, refer to the Reedy River Water Quality Group’s video on Riparian Buffers!

August’s results and the SC state standards are included for comparison below. All results were within SC state standards. 

• pH is a way of measuring the H+ ions in a water sample, or if the sample is acidic or basic. pH is influenced by the concentration of acids in rain, and the types of soils and bedrock present in the watershed. Ideally, rivers will have a neutral pH, or a value of 7.

• The available dissolved oxygen (DO) in a water sample is important for fish health and life within a body of water. DO can increase in lower temperatures, turbulence in the water, photosynthesis in the stream, and diffusion from the atmosphere. DO can decrease in higher temperatures, in slow-moving and deep water, and in the presence of decaying organic matter.

• E. coli Bacteria counts are found by incubating a water sample that was placed on a medium, then counting the number of coliform forming units. These values are higher in areas where animals are present so always remember to pick up after your pets and don't feed the geese in the park!

• Turbidity, the cloudiness of water, is quantified with the unit of measurement “NTU,” which stands for “Nephelometric Turbidity Units”. Low NTU readings indicate clearer water and high readings indicate very turbid, or cloudy, water. NTU readings typically range from 1 to 4,000, with 1 being clear water and 4,000 having very little transparency and high turbidity (think of the cloudiness of milk). 

Sign up to join the FoRR monitoring team HERE!

Find an SC Adopt-a-Stream event near you to become certified HERE!

The FoRR Monitoring Team uses SC Adopt-a-Stream techniques and has its own monitoring kits, thanks to Ivy Salon and The Greenville Zoo Conservation Fund.