NASHVILLE, Tenn. (May 5, 2021) – The Water Quality Team, a component of the Water Management Section within the U.S. Army Corps of Engineers Nashville District, routinely collects water quality information at the 10 reservoir projects in the Cumberland River Basin.
Mark Campbell, Water Management Section hydrologist, said the results obtained from these surveys makes it possible for the Corps of Engineers to determine physical, chemical, and biological metrics to better assess water quality conditions throughout the system.
“We are very fortunate to have relatively good water quality in the Cumberland River Basin at all of our reservoirs,” Campbell said. “The data that we collect is submitted to the states of Tennessee and Kentucky for evaluation against their specific water quality standards.”
The Water Quality Team conducts at least three full sampling trips at all 10 projects to capture the growing season during the spring, summer, and fall. These trips typically consist of reservoir profiles for water temperature, dissolved oxygen, conductivity, and pH. Water samples are also collected which are analyzed for nutrients, metals, algae, and chlorophyll.
“We conduct a general water quality assessment in the project tailwater sites, reservoir stations, and major tributaries or inflows,” Campbell said.
These surveys are used to monitor temperature and chemical stratification and to supply water managers with information to improve water quality conditions in releases. Water temperature and dissolved oxygen levels released from these projects directly influence water quality conditions for the mainstem of the Cumberland River system.
“The oxygen depletion in the storage reservoirs typically begins in the springtime, degrades into the summer, and the lowest levels are observed in the early fall. Measures taken to improve the dissolved oxygen in releases include opening air supplies for hydropower turbine venting and in some occasions releasing water from either a sluice gate or an orifice gate to mix a higher oxygen blend into the discharge,” Campbell explained.
When checking water samples for dissolved oxygen levels, the team can have an immediate influence on water management operations to improve water quality conditions that benefits aquatic life downstream. The tailwaters of Center Hill, Dale Hollow and Wolf Creek Dams are also trout fisheries so there is a lot of focus on water temperature control and dissolved oxygen in these stretches of the Caney Fork River, Obey River and Cumberland River.
“For example, when we’re sampling at a reservoir and record low dissolved oxygen levels in the turbine discharge just downstream of the dam, we will contact our water managers and can often in real time implement changes to improve the water quality in that release,” Campbell said.
The Water Quality Team also observes conditions and tests when necessary for harmful algal blooms, which are caused by some species of blue-green algae that produce toxins in waterbodies under certain conditions.
Sarah Pedrick, Water Management Section biologist, said people are understandably concerned about HABs because they’ve heard blooms may cause health issues for humans and pets. HABs can form within a day and be gone the next, so if samples are not taken during that timeframe, the data may be inconclusive, she added.
“While effects to human health can occur, they seem to be rare in our region,” Pedrick said. “Our team makes visual observations of the Cumberland River Basin reservoirs and monitors water samples for elevated blue-green algae conditions.”
Pedrick suggests making a visual assessment of the waterway when recreating and to avoid an area if it appears to have foul-smelling scum, foam, froth, or paint-like spill. If these conditions are seen, they can be reported to the lake resource manager at https://www.lrn.usace.army.mil/Contact/Contact-a-Lake/. Be sure to find a different access point into the water at a different location.
When testing for BGA, if samples are high enough to warrant further investigation, the Corps expedites test results. However, recent sampling indicates there is little cause for concern about HABs or excess BGA in the Cumberland River Basin.
Pedrick said she sometimes gets to see sunrises and sunsets on long days collecting water samples, but the work gives her a lot of satisfaction knowing that monitoring water quality is both beneficial and meaningful.
For additional information about HABs and BGAs, go to the Kentucky Division of Water at https://eec.ky.gov/Environmental-Protection/Water/Monitor/Pages/HABS.aspx, Tennessee Department of Public Health at https://www.tn.gov/health/cedep/waterborne-diseases/harmful-algal-blooms.html, and Tennessee Department of Agriculture at https://www.tn.gov/agriculture/businesses/animals/animal-health/blue-green-algae.html.
(Editor’s Note: Biologist Ashley Fuentes contributed to this article. The public can obtain news, updates and information from the U.S. Army Corps of Engineers Nashville District on the district’s website at www.lrn.usace.army.mil, on Facebook at www.facebook.com/nashvillecorps and on Twitter at www.twitter.com/nashvillecorps.)