Rainwater backup has been causing problems for some in Lafayette.

Two weeks after the last heavy rainfall, a faint stench of sewage still lingered among mud covering some of the coulee-facing backyards lining Girard Park.

Kirk Hornung said the odor is a remnant of the “black ooze” of raw sewage that’s spewed out onto his and neighboring properties for the past year each time a storm roars through the city with excrement, toilet paper and sometimes tampons and condoms spilling out from the manholes behind his and other homes on Girard Woods Drive.

“It’s a poo geyser,” Hornung said, as he stood in his yard Wednesday.

Hornung and his wife, Wendy, in 2009 moved in next door to Jim and Katie Diaz, who moved into their home in 1989. Both families’ properties are beside a public pathway that neighborhood residents and students traverse to reach the park or the University of Louisiana at Lafayette campus.

But each time it’s rained over the past year, the untreated sewage spills into the backyards and creates a mucky lake over the grass that blocks the pathway and causes a serious stench, Hornung said. The contaminated sludge spills into the coulee that drains into the Vermilion River.

Although the families alerted the city about the problem, its patchwork attempts to fix it — first, by extending the manhole covers above ground to relieve some of the pressure, and second, by bolting the manholes shut — only pushed the eruptions further down the sewer lines to neighboring properties, Hornung said.

“It’s kind of like a game of whack-a-mole: You hit one and it pops up somewhere else,” Hornung said.

Neither family recalled having problems until a year ago, but they said the numerous overflows not only cause a smelly nuisance but a health hazard each time the untreated sewage erupts.

The families filed a joint lawsuit in March against Lafayette Consolidated Government seeking a court order mandating the city fix the defects. The suit also seeks an injunction against the city continuing to pollute their properties.

Some downtown Lafayette employees also were recently requesting relief after the same downpours that caused the sewage overflows near Girard Park caused some downtown storm water drains — which flow into different pipelines than those that carry sewage beneath the city — to overflow above the sidewalks and into their businesses near the corner of Jefferson and Convent streets.

On a particularly heavy evening downpour March 18 — also the same storm that caused the most recent sewage overflow at the homes near Girard Park — employees of Pop’s Poboys and Carpe Diem! Gelato had to sweep out a couple inches of water from their businesses.

“You couldn’t see the sidewalks,” said Rick Rowan, the gelato shop’s manager.

City employees were beneath Jefferson Street on Wednesday to inspect the storm water lines and soon cleaned out about 300 feet of pipe where roots from the American bald cypress trees that line the street had invaded the pipelines, said Tom Carroll, Public Works director for Lafayette Consolidated Government.

Back near Girard Park, city employees on Wednesday were working on the pipelines near the Hornungs’ 1940s home, which, like all the homes throughout the neighborhood, is surrounded by mature trees the city tells them may have invaded the sewer line.

“They’re playing a constant battle down here,” Hornung said, acknowledging the challenges of having adequate drainage with Lafayette’s low-lying flatness, soft soil and ample flora.

Terry Huval, director of Lafayette Utilities System — which provides electric, water and sewer services within the city limits — said if an underground sewer line is intruded upon, it can begin taking in rainwater, especially during heavy downpours, that causes a backup. But to solve sewage problems takes “some finesse,” he said.

The city’s initial work on the problem was an attempt to quell it while working on a lasting solution that would not simply push the pressure farther down the sewer lines, Huval said.

“That’s what we had to go through to be sure we didn’t inadvertently cause more problems,” Huval said Wednesday. “I believe the work that we’ve done there is about done and will keep the back flow from happening again.”

Downtown, Caroll said the discovery of invasive roots clogging the storm water lines beneath downtown Jefferson Street means all the storm water lines there will be evaluated for potential clogging.

Carroll said the trees were sold to the city about a decade ago as a tree with a noninvasive root system.

“That appears to be maybe adverse to what we’re finding there,” Carroll said, adding the roots have long been damaging the irrigation systems built into the sidewalk landscapes. “It’s been a constant issue.”

Follow Lanie Lee Cook on Twitter, @lanieleecook, or contact her by phone at (337) 534-0825.