Flirting with disaster?
If sewage contributed to 1998s leptospirosis epidemic, we may still have a problem.
In the spring of 2001 Joe Mackay left a message with the Springfield Metro Sanitary District. He'd seen sewage flowing out of three manholes in the Lick Creek Wildlife Preserve near Lake Springfield.
The next day, Mackay says, sewage district director Andy Alvey called him back, asking "What are you doing hunting down there?" Mackay, a nature lover who lives in the area, replied that he wasn't hunting, just walking his dog. He says Alvey pressed his point: "That's a game preserve." Later in the conversation, Mackay recalls, Alvey told him that workers had already walked the sewer line in question and had seen nothing wrong. "I wasn't going to argue with him," Mackay says.
Though he encountered the overflowing sewers several more times that year and the following spring, Mackay never contacted anyone else to report the problem, until he read last week's Illinois Times story on the leptospirosis outbreak of 1998. He's also seen three or four other manholes overflowing in the woods behind the Piper Glen Golf Course. Both areas are near where the Lick and Polecat creeks feed into Lake Springfield. The manholes are raised on concrete cylinders one- to four-feet-high because flooding is common.
Mackay speculated that storm water infiltrating the sewers could create pressure in the pipes, causing sewage to rise into the cylinders and lift the manhole covers off their bases and onto the ground nearby. Sewage also leaks out through cracks and a seam around the middle of the cylinder. "It comes out everywhere--there's a lot of pressure," Mackay says. "I've seen it squirting two or three feet out the sides from those cracks." The raw sewage--toilet paper and all--streams across the marshy bottom toward the creeks. Sometimes flooding waters rise over the manholes, carrying the sewage directly into the lake.
Alvey doesn't remember receiving Mackay's phone call, but if the manholes were overflowing, he says, "hydraulic overload" might explain it. These manholes serve a 30-inch sewer pipe that is close to capacity and feeds into the Chatham North pumping station. If the pumps have difficulty handling increased flow during heavy storms, sewage could possibly back up into manholes. "Most of the manholes in that area have bolt-down lids, so I'm having a hard time understanding how that could happen," Alvey says. He couldn't explain why Mackay found covers on the ground.
During an interview for last week's story, Alvey had groaned at the mention of the leptospirosis outbreak. "We went around and around about that," he said, and medical investigators had ruled out the sewers around Lake Springfield. When I explained that sewer rats could be a source of leptospira bacteria, he asked who had told me that. Hearing the information came from someone at the Environmental Protection Agency, he scoffed: "The sewer system around Lake Springfield is not responsible."
Mackay could not say whether the manholes were leaking earlier than 2001, when he began walking his dog by them. Measurements for a harmless variety of E. coli are taken in Lake Springfield twice a month to indicate whether bacteria of all kinds are on the rise. The Illinois Department of Public Health recommends closing beaches when these readings rise above 235. In June 2001 bacteria levels reached 5,830 in the Lick Creek branch of the lake, where Girl Scout and Boy Scout campgrounds are located. The Sugar Creek branch, where high bacteria counts have also been measured, has two pumping stations near its shores. If these pumping stations are overtaxed, it's possible sewage could be backing up behind them and leaking out as well.