Overview
- The die-off was first documented on Friday and spans roughly 20 miles from where Peachtree Creek enters the river toward West Point Lake, with Chattahoochee Riverkeeper estimating thousands of dead fish of multiple species.
- Officials say a short, intense storm that sent large volumes of warm, polluted stormwater into an already low river likely precipitated a sudden plunge in dissolved oxygen, the immediate cause of the suffocation event.
- Riverkeeper crews reported sewage‑related items and heavy urban debris in the affected stretch, and they say overflow from an underground tunnel and treated discharges may have contributed to low‑oxygen water entering the river.
- City and state agencies including Atlanta’s Department of Watershed Management and the Georgia Environmental Protection Division are conducting joint sampling and field testing, and the city says preliminary data show the tunnel system 'operated as designed' while full lab results remain pending.
- Authorities advise people to avoid the impacted stretch as oxygen levels begin to recover, and experts warn the event highlights strains on stormwater and sewer infrastructure and the wider risks posed by more intense urban rainfall to river health and local recreation.