After a week spent calculating the size of a sewage spill that lasted more than two days, the Macon Water Authority concluded that Sabbath Creek was contaminated with 11.5 million gallons of sewage.
With the exception of several spills last fall related to the Macon levee, the spill lasting from Feb. 5 to Feb. 8 at the dead end of Lennox Drive appears to have been the authority’s largest ever. It was 15 times larger than 86 sewage spills from last year combined.
“This was the biggest one I’ve ever seen out of our sewer system,” said Darryl Macy, a six-year employee who is sewer conveyance manager for the authority. “It just kept going and going and going.”
The dead end of Lennox Drive was the site of 14 sewage spills last year. The Lennox spills, which occur near a dirt easement that runs behind the Riverview neighborhood, are the result of rainwater overwhelming the sewer lines.
Eight of the 14 spills there in 2009 were reported as larger than 10,000 gallons.
However, authority officials said they realized late last month they had been vastly underestimating the volume of sewage spills related to rain. Although the authority had entered into a voluntary agreement with the state to calculate such spills using a certain method, it had never used the method. Instead, workers were using a simpler visual estimate to determine volumes.
Authority leaders say they changed their methods and notified state environmental regulators as soon as they realized the mistake.
Tony Rojas, the authority’s director, had said the authority would try to recalculate the size of last year’s largest sewage spills, which generally occurred repeatedly at the same locations, such as Lennox.
But Tuesday, Mark Wyzalek, authority environmental compliance manager, said the authority would not be recalculating the old spills because it doesn’t have enough information.
The method the authority agreed to use requires measuring the height of water as it flows out of manholes and the position of the manhole cover during the spill. Without photos, the authority no longer knows this information about the old spills.
Wyzalek said he explained this to Environmental Protection Division officials last week, and he was told it was OK not to recalculate the spills.
Even if some of the past Lennox Drive spills were larger than reported, none was as large as this one, Macy said. Most others lasted 24 hours or less, he said.
Authority records show much more rain falling during some of the 2009 spills than the 1.35 inches that fell Feb. 5.
Macy and Wyzalek said this spill might have been worse because the ground is now even more saturated and unable to absorb any more rain. “Of course we don’t want these spills, but that’s just how it is right now with these historic weather conditions,” Wyzalek said. Last year was the third-wettest on record for Macon.
The authority is trying to combat the problem by installing a new 36-inch sewer line for $4 million.
It also is using a $2 million loan through the Georgia Environmental Facilities Authority to find and fix leaks and other problems in sewer lines in the areas that drain to the sewer line.
To reach writer S. Heather Duncan, call 744-4225.