Researchers take a break from painting town red, try the river

Rhodamine dye enters the Savannah River with dissolved oxygen near the downriver DO site, Aug. 25.

SAVANNAH, Ga. – Did you hear the one about the biologists who stained the Savannah River red? Apparently they were dye-ing for results (ba-dum pah)! Seriously though, folks …

All dad jokes aside, last week biologists and environmental engineers from LG2 Environmental Solutions, Inc. and Tetra Tech, Inc., used a concentrated red dye to track the movement of dissolved oxygen throughout the Savannah River.

“Rhodamine dye is a specific dye for water tracing studies,” said Rick McCann, geologist and senior project manager with LG2 Environmental Solutions, Inc. “It’s really red and does a marvelous job staining the river. So we see a visual indication of the dye, but we also detect it with our instruments even when we can’t detect it visually.”

Researchers injected the non-toxic dye at U.S. Army Corps of Engineers Savannah District’s two Dissolved Oxygen (DO) Injection System sites — one upriver near Plant McIntosh in Rincon, Ga., and the other downriver site on Hutchinson Island – as super-oxygenated water left the sites on two separate days.

They then used instruments called Sondes on pre-positioned buoys and in boats to track the dye and the dissolved oxygen’s movement throughout the water column.

Researchers test for dissolved oxygen in the Savannah River with a super dye test, Aug. 24-26.

The DO sites are designed to help mitigate for the loss of oxygen as the harbor is deepened from 42 to 47 feet as part of the Savannah Harbor Expansion Project.

The extra oxygen added to the river, specifically during the summer months when dissolved oxygen is naturally lower, will benefit fish like the endangered shortnose sturgeon and Atlantic sturgeon as they make their way upstream and back downstream again to the Atlantic Ocean.

On the first day of testing, researchers injected 60 gallons of dye at the upriver DO site as super-oxygenated water entered the river. According to Jim Greenfield, an environmental engineer with LG2 Environmental Solutions, Inc., they tracked the dye downstream as far as Highway 17 (Talmadge Bridge) just past the Garden City Terminal.

The second day, a similar test was run on a rising tide, which carried the dye and dissolved oxygen from the downstream DO plant upriver into the turning basin and areas of the little back river.

On the third and final day, researchers used Sondes to continue to track the dissolved oxygen as it dispersed throughout the river.

“This (test) tells us where the oxygen is going, how fast the oxygen is mixing and how well it’s mixed through the system,” Greenfield said.

Now that the testing is complete, the researchers have begun the painstaking process of entering all the data into a water quality model, which, according to Greenfield, will help determine the impacts and assistance that the dissolved oxygen injection sites are giving to the harbor.

And that, especially if you’re a shortnose or Atlantic sturgeon, is no joke.

~ Jeremy S. Buddemeier, Corporate Communications Office

About U.S. Army Corps of Engineers Savannah District

The U.S. Army Corps of Engineers Savannah District oversees a multimillion dollar military construction program at 11 Army and Air Force installations in Georgia and North Carolina. We also manage water resources across the Coastal Georgia region, including maintenance dredging of the Savannah and Brunswick harbors; operation of three hydroelectric dams and reservoirs along the upper Savannah River; and administration of an extensive stream and wetland permitting and mitigation program within the state of Georgia. Follow us on Twitter @SavannahCorps and on
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