How clean is the Bayou Vermilion?

The Vermilion River has come a long way since earning the dubious distinction of “Most Polluted River in America” in the 1970s.

Conservation efforts through the decades improved the water significantly, putting the bygone era of flammable American rivers behind it. Organizations like the Bayou Vermilion District and Teche-Vermilion Fresh Water District work to bring the river to a place of general safety for boating and sometimes even swimming.

But how safe is the Vermilion? The answer is complicated. 

Enter at your own risk

In short: It depends where you are. The further south you get, the more contaminated the water. 

Regulators advise against swimming in the Vermilion. And there’s some dispute about whether the river is safe for boating. 

Agricultural runoff, poorly managed septic systems, dog waste and other waste from animals in the watershed deposit colonies of bacteria in the water. High concentrations found between 2018 and 2020 led the Louisiana Department of Environmental Quality to “impair” large sections of the river against boating in a 2022 report. That came as a surprise to water quality experts. 

“This is the first year that fecal has increased to the level that makes the DEQ list it [not supporting] secondary contact,” says Whitney Broussard III, an environmental scientist who advises the Teche Vermilion Water District. “When this hit, it surprised a lot of people; we didn’t expect this.” 

For a river to be considered impaired, samples must exceed the threshold limit for more than 25% of the “season.” Boating season is year round, while swimming season is from May to October. For boating, the Ambassador Caffery Parkway bridge to the Vermilion Bay was considered impaired for 27% of the year and 50% of the swimming season.

To be clear, “impaired” doesn’t necessarily mean unsafe. DEQ urges people to make their own judgments about entering the water and suggests they take into account recent rainfalls and pumping activities near the river’s headwaters. The contamination numbers fluctuate as waste is flushed into the Vermilion by rainfall or cleaned by pumps operated by the Teche Vermilion Fresh Water District. 

Timing is everything

According to DEQ, testing concentrations of 400 or more colonies of fecal coliform bacteria per 100 milliliters of water is considered unsafe for swimming. Two thousand colonies and above is the unsafe threshold for boating, or what regulators call secondary contact. 

Samples collected from the Ambassador Caffery Parkway bridge south to Vermilion Bay tested as high as 25,000 colonies, according to data collected between 2018 and 2020, the most recent available. Lower but still relatively high levels of fecal coliform bacteria were present north of the bridge to the river’s headwaters. 

But the state numbers don’t tell the full story. Teche Vermilion Executive Director Donald Segrera says the DEQ results are only a snapshot of the river’s water quality. 

Big picture, he says, the river is generally safe for boating, according to samples his organization takes monthly. He says the river is safe for secondary contact the vast majority of the year and safe around half the time for primary contact. Near the headwaters, where the district pumps in fresh water from the Atchafalaya River, is safe all the time.

“Looking at the recent results of our sampling project, we would not find that it would be considered impaired for secondary contact,” Sagrera says. 

Timing is also key for data collection, he says. When Louisiana is seeing considerable drought or in between rainfalls, samples will show lower concentrations of bacteria. South Louisiana is a humid subtropical climate and receives around 50 to 70 inches of rain a year and has nearly a 1 in 4 chance of raining every day. 

Sagrera’s point is corroborated by some DEQ data. A number of those same sites that showed thousands of fecal coliform colonies in samples showed as few as 0-50 colonies at other times during the year. 

So is the river safe? Well, it depends. But one thing is clear: There is room to improve. 

Efforts to clean up the river have been fairly successful in improving water quality, but there remain plenty of uphill battles to fight. 

Increasing concentrations of bacteria are a cause for concern for Whitney Broussard, the environmental consultant. He helped create a long-term water quality monitoring system for the fresh water district and now acts in an advisory role for the organization. 

“This is a battle cry,” Broussard says. “We’ve been doing really good, and we’re getting better, and people are taking care of the water; it’s no longer a trash heap … but we still have some work to do.”

Water Quality: Swimming upstream

The Vermilion River is in a similar situation to many rivers in Louisiana. A 2022 Louisiana Water Quality Integrated Report found that 56% of Louisiana’s rivers do not support primary contact. But 94% of its rivers support secondary contact. This report tested approximately 350 rivers in Louisiana. 

The main causes of contamination are from farming livestock and poorly maintained septic systems along the river. If those septic system owners do not clean out their sludge buildup or have properly functioning aerators, harmful bacteria like E-Coli can seep into the soil and drain into the waterway. High concentrations of fecal coliform can lead to infections for those entering the water (or tipping over their canoes). 

One of the most effective ways to momentarily clean the river is by pumping fresh water from the Atchafalaya Basin into the river. That’s exactly what Teche Vermilion Fresh Water District does.

A prolonged drought in Louisiana allowed the pump station to run for 200 days last year. The water from the Atchafalaya is extremely clean, Sagrera says. All that clean water flushes the pollution away.

“That water [Atchafalaya] has never been impaired, and we’ve sampled it over 60 times,” Sagrera says. 

While more fresh water would help flush out bacteria, keeping the bacteria from getting into the water in the first place is crucial.