News From The River

See the Latest Water Quality Monitoring Data from the FoRR Monitoring Team!

FoRR took to the river on August 21 to monitor three sites in the Reedy River watershed. Our sites include the following:

Site #1: Reedy River just downstream of Swamp Rabbit Cafe

Site #2: A small tributary of the Reedy River in Falls Park 

Sit #3: Reedy River on Mauldin Road upstream of ReWa's headquarters

The pH results for August were consistent with our findings in July, with sites only showing small decreases from last month’s results. 

The air and water temperatures for August’s sampling event increased again, but with much smaller margins of increase than last month. The air temperatures at all three sites ranged from 24C to 27C and the water temperatures ranged from 23C to 24C. This month’s results show an average air temperature increase of 0.83C and 0.33C increase in water temperatures across all three sites. The overall average air temperature was 25.67C (compared to 24.83 last month) and the overall average water temperature was 23.5C (compared to 23.17 in July). 

August’s dissolved oxygen (DO) results remained fairly consistent across the three sites, with both Mauldin Road and Swamp Rabbit Cafe showing slightly increased DO levels (this is a good thing!) and Falls Park showing a slight decrease. Mauldin Road’s DO levels increased by 1.0 mg/L and Swamp Rabbit Cafe’s DO increased by 0.5 mg/L. Falls Park, on the other hand, decreased by 1.0 mg/L to only 5.4 mg/L. We noted low flow at the Falls Park location. This site is on a tributary to the Reedy River instead of on the River itself like our other two sites. Low water flow can contribute to low DO levels since one of the ways oxygen is introduced to stream water is through turbulent or “well-mixed” areas in the streams that “stir” oxygen into the water (known as riffles). When there is very little turbulence or mixing, on the other hand, it becomes difficult for oxygen to become incorporated into the water, resulting in lower levels of dissolved oxygen. We can infer that this is one factor contributing to the lower DO levels in Falls Park this month and the main reason that the other two sites do not show the same DO level decrease this month. The average of the DO results at all three sites is 6.37 mg/L, up 0.17 from July’s average DO level. 

The E. coli bacteria results were much higher in August than they were in July. July’s results ranged from only 200-267 cfu/100mL at all three sites, whereas August’s results ranged from 367-467 cfu/100mL. Swamp Rabbit had the lowest bacteria count this month at 367 cfu/100mL, Falls Park came in at 400 cfu/100mL, and Mauldin Road had 467 cfu/100mL. While these results are higher than the “high” threshold of 349 cfu/100mL, and certainly higher than our results in recent months, they fortunately do not exceed the “problematic” threshold of 1,000 cfu/100mL. Many other volunteers within the Reedy Watershed have also been registering higher-than-usual bacteria levels while sampling this month. Sometimes, even with the flow levels being somewhat low overall, the flashy summer storms can cause untreated waste to be introduced into the water system during periods of flash flooding or when large amounts of runoff are introduced to the river at once. This could be the case due to the high frequency of afternoon storms with large amounts of rain falling very quickly in the last month. In addition to flashy storms introducing new bacteria, low flow periods can cause the levels of bacteria in the water to appear more concentrated due to the lesser volume of water present to dilute the bacteria. We are keeping a close eye on any potential “hot spots” where bacteria may be entering our waters and will continue to report back if we identify any issues. We hope to see E. coli levels return to normal (under 349 cfu/100mL) next month. 

This month's turbidity remained fairly consistent with last month’s results. Falls Park and Mauldin Road showed no change again and both had levels of 5 NTUs, the same turbidity reading we measured in June and July. Swamp Rabbit Cafe decreased to 5 NTUs as well, down 2 NTU’s from last month’s result of 7 NTUs. This means the water was fairly clear at all three locations this month. 

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

August 2023 Monitoring Results:

  • 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.

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