BAYOU MANCHAC — There’s a stink on the bayou, some residents say, but it’s not clear what the source is.
Jonathan Scott, president of a community group tracking the health of Bayou Manchac, said Friday the foul odor has been evident the past four days after heavy rains.
The bayou runs along the borders of East Baton Rouge, Ascension and Iberville parishes to the Amite River.
Scott said he has spoken with residents who tell him they, too, believe the smell is of raw sewage.
Scott said ribbons of gray, greasy film can also be seen floating in bayou eddies.
Scott said the Bayou Manchac Group has traced the stench and film up to where Alligator Bayou empties into Bayou Manchac at a floodgate in Iberville Parish.
“Now where this is coming from, we don’t know,” he said Friday.
Louisiana’s Department of Environmental Quality has received complaints about the situation and planned to send an examiner out Friday afternoon, said Jean Kelly, DEQ spokeswoman. Results were not immediately available Friday.
Iberville Parish President J. Mitchell Ourso said he also planned to send personnel on Saturday to check on the issue.
About 4 p.m. Friday, breezes were tainted by a smell akin to rotten eggs and sewers.
The odor periodically came and went at the Alligator Bayou floodgate, as water with a greyish, white film flowed out along with bits of vegetation.
The gate was open, allowing water from Alligator Bayou, which drains Spanish Lake, to flow into Bayou Manchac.
As the film floated by Friday, a man fished from the floodgate structure, saying he was casting his cork and lure into Bayou Manchac for the thrill of the catch, not dinner.
Scott, who says he is an environmental engineer, speculated recent heavy rains may have caused a sewage overflow from one of the dozens of treatment plants that discharge into Spanish Lake.
DEQ’s Kelly said the floating film and smell could be coming from anywhere, but did say a lot of oxidation ponds and subdivision treatment systems are in the area.
“This is something that happens this time of year when we have a lot of rain,” she said.
In the two-week period between July 13 and Friday, Gonzales received 5.99 inches of rain, said Phil Grigsby, a National Weather Service meteorologist at the Slidell forecast office.
Between July 19 and July 22, Gonzales, the nearest observation station to Spanish Lake, received a 4.82 inches. The heaviest rain fell July 21, with 2.1 inches.
“It’s been very, very wet,” Grigsby said.
Iberville Parish government has no treatment systems on the east bank, but the sizable St. Gabriel sewage treatment system does ultimately discharge into Spanish Lake, DEQ permit records say.
Mayor Lionel Johnson Jr. said in a text message that a crew canvassed the area Friday after an inquiry and detected an odor.
But he said the crew also checked lift stations and found no evidence of abnormal discharges during the past few weeks.
He said officials would continue to monitor the system.
The treatment plant at Elayn Hunt Correctional Center in St. Gabriel discharges into the Mississippi River, said Pam Laborde, Louisiana Department of Corrections communications director.