ATHENS — A total of 3,009 game and nongame fish, including 17 threatened slackwater darters, were killed in a May sewer overflow into an unnamed tributary of Swan Creek in Athens, according to the results of a state investigation into the fish kill.
Investigations into the fish kill have been completed by both the Alabama Department of Environmental Management and Alabama Department of Conservation and Natural Resources, said ADEM spokeswoman Lynn Battle.
“The fish kill report has been finalized and is now being reviewed for compliance determination by (ADEM’S) water division,” Battle said.
The fish kill was reported to the U.S. Coast Guard’s National Response Center on May 22 by a Tennessee man who was walking on the Swan Creek trail and noticed about 50 dead fish from the pedestrian bridge over an unnamed tributary to Swan Creek, according to the Department of Conservation and Natural Resources’ investigative report.
The cause of the kill was determined to be a sewer overflow from a manhole on East Pryor Street, causing low dissolved oxygen levels, according to the report. The DO levels were measured at the pedestrian bridge and upstream of the sewer overflow.
The report showed the kill was an estimated 6,200 feet in length.
The report puts the price tag for replacing the fish and investigative expenses at $3,788.63, though the estimated value of the slackwater darters hasn’t been determined.
The dead fish weighed at least 60.5 pounds, according to the report. The report also noted that many fish, especially the smaller fish, likely disappeared because they decomposed or were eaten by scavengers and were unaccounted for by the fish-kill investigators.
“Therefore, the enumeration and valuation of this fish kill is considered to be conservative and likely underestimates actual damages,” according to the report.
The report showed the species most impacted by the kill were the large-scale stone roller, minnow, darter and redbreast sunfish.
The slackwater darter, which grows to a length of about 2½ inches, is listed as threatened by the U.S. Fish and Wildlife Service.
Mayor Ronnie Marks said last month that the city reported the incident to ADEM, and Athens Utilities Water Services posted warning signs along the creek.
ADEM’s preliminary sewer overflow event reporting form said employees had plugged a sewer line while performing maintenance on it and left the plug in too long, resulting in the overflow. The form indicated the overflow began at 8 a.m. May 22 and stopped at 10 a.m. that day.
The ADEM form reported that the discharge didn’t reach designated swimming water, and no public water supply intake locations were affected.
According to Marks, the overflow incident was “100% worker error.”