ATLANTA – Following the significant rainfall event on Wednesday, May 20, 2026, and the fish kill along the Chattahoochee River, the City of Atlanta Department of Watershed Management (DWM) has retained Brown and Caldwell, an engineering and consulting firm, to conduct an independent evaluation of system operations at the West Area CSO Tunnel Treatment Facility and the associated tunnel operations. 

The review will assess rainfall conditions, system performance during the event, and the source of reported sludge residue, as well as determine whether observed conditions are directly related to the storm or other contributing factors. The evaluation will also include recommendations to strengthen operations, maintenance, and system readiness. 

“We can only prevent what happens in the future by fully understanding what happened in the past,” said DWM Commissioner Greg Eyerly. “This independent review will help ensure we discover the root cause of the fish kill. We cannot rely on theory and speculation, we have to support our findings with data while identifying opportunities to strengthen system performance.” 

This effort is being conducted in coordination with regulatory requirements under the City’s Consent Decree and in collaboration with the Georgia Environmental Protection Division (EPD). 

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