Atlanta metro downpour leads to massive fish kill on the Chattahoochee River

A massive fish kill in the Chattahoochee River west of Atlanta was reported Friday by environmental nonprofit Chattahoochee Riverkeeper. Jason Ulseth, general manager of the Chattahoochee Riverkeeper, told CNN he found the dead fish when he went out on river patrol Friday morning.

Ulseth estimates thousands of fish, some weighing 20 to 30 pounds, have died along about 20 miles of river along the western border of Fulton County. He found spotted bass, catfish, carp, shad and striped bass; floating, scattered on the shores, caught in piles of debris and low tree branches.

According to Ulseth, an unidentified, foul-smelling black substance also covered the river banks.

“It was such a disaster to see everything die,” Ulseth said.

The death follows a severe storm that dumped 3 inches of rain per hour on the Atlanta metro area on Wednesday. flooded area streets caused flash flooding.

Investigations into the cause of the fish kills are ongoing by the Chattahoochee Riverkeeper and the City of Atlanta Department of Watershed Management. Both sides believe drought and heat played a role in this death.

Due to the long drought, the river was flowing very little when the storm came. There was not enough cold water to soften the flow of significantly warmer rainwater heated by urban infrastructure.

“When the heavy rainfall event hit the downtown urban core, the river had little buffer capacity to absorb nutrients and thermal loads. While flow on the Chattahoochee River was very low, flow from urban streams into the river was very high. The high temperature and time of day may have contributed to additional thermal load and stress on aquatic life,” Lena Hardy, spokeswoman for the City of Atlanta Watershed Management Department, told CNN.

But Chattahoochee Riverkeeper believes stormwater and sewage discharge from an underground tunnel system built to hold excess wastewater also likely contributed to the incident.

“Currently, the Chattahoochee Riverkeeper believes that low flows in the river due to drought, heavily contaminated stormwater from Peachtree Creek, discharges of untreated combined sewage from the City of Atlanta into Peachtree Creek, and additional treated discharges from wastewater facilities into the Chattahoochee River create the conditions for fish kill.” the organization said in a press release on Saturday..

Ulseth said she found condoms, menstrual products and wet wipes in the river, which she said strongly indicates sewage pollution. Other trash more consistent with stormwater runoff also accumulated with the dead fish, he said.

Moreover, according to Ulseth, the affected part of the river begins where an overflow structure connected to the tunnel system flows into the river.

Hardy said as of Monday “preliminary water quality data shows the tunnel system is operating as designed and within permitted water quality standards. However, not all laboratory testing has been completed and DWM is still investigating the impact to the river and its relationship to fish kills.”

The lawsuit over sewage pollution in the Chattahoochee River dates back to the 1990s and is ongoing, Ulseth said.

CNN also reached out to the Georgia Department of Environmental Protection and the Georgia Department of Natural Resources. The natural resources agency referred CNN to the Georgia Department of Environmental Protection.

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