ATLANTA — A combined sewer overflow from the city of Atlanta caused the fish kill that left an estimated 44,509 fish dead along nearly 16 miles of the Chattahoochee River in May, according to a state investigation.
The Georgia Department of Natural Resources’ Wildlife Resources Division concluded that about 5.94 million gallons of untreated or minimally treated sewage and stormwater overflowed into Peachtree Creek during a roughly four-hour emergency discharge on May 20. Investigators found that the overflow triggered low-oxygen conditions in the river, which proved fatal to fish downstream.
State crews surveyed the river two days later, documenting dead fish along a 15.74-mile stretch below the confluence of Peachtree Creek and the Chattahoochee. They also found black sludge on the riverbanks and river bottom, a strong sewage odor and debris associated with sewage overflows, including wipes and paper products.
Upstream of Peachtree Creek, investigators reported live fish and no similar signs of contamination.
Although dissolved oxygen levels had recovered by the time crews arrived, U.S. Geological Survey monitoring showed oxygen concentrations dropped to 1.5 milligrams per liter after the overflow — low enough to kill fish. Investigators said persistent drought and low river flows likely worsened the event by reducing the river’s ability to dilute the wastewater.
They concluded the overflow itself caused the fish kill.
The state estimated the dead fish were worth $838,603.96, bringing the total cost of the incident to $848,203.09 after investigative expenses.
The report does not address potential enforcement actions. However, it establishes the state’s findings on the cause of one of the largest documented fish kills on metro Atlanta’s stretch of the Chattahoochee River.
Byline: Staff Reports
Source: The Jonquil Journal
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