East Baton Rouge Parish plans to sue neighboring Iberville Parish to prevent water-inflated flood barriers known as AquaDams from be used to protect against high water on Bayou Manchac, the city-parish mayor-president said Friday. 

Iberville Parish President Mitch Ourso said earlier that his administration was staging the AquaDams to protect against possible flooding in the Spanish Lake area as Tropical Storm Barry approached the Louisiana coast.

"I did not want to do it," Mayor-President Sharon Weston Broome said of the pending lawsuit, "but I am getting a deluge of communications from people who live in that area. It's my hope that we can find a path forward between the two of us, so this doesn't have to transpire."

Barry is expected to dump 10 to 20 inches of rain on the region, with localized maximums of 25 inches. Ourso said Manchac Road in his parish was closed to thru-traffic early Friday to prepare for installation of the dams, when needed. 

"I don’t know what's going to come down, but I have to be prepared," he said early Friday.

Broome said she understands that Ourso feels he has to do what he believes is necessary to protect his constituents but said she is doing the same for hers. She said she believes the AquaDams would be an infringement on the residents of her parish.

She said she considers Ourso a colleague and the two had already spoken about the issue by mid-Friday morning.

Broome said she had instructed her Parish Attorney's Office to file the lawsuit, but could not immediately say if the suit had actually been filed, likely some kind of emergency injunction.

The parish court system was closed Friday and parish attorneys would need special preparations to file the legal action. But she said she could still pull the suit if the two parish leaders can find that "path forward." As of 5 p.m. Friday, the lawsuit had not been filed.

Phil Breaux, an attorney for Iberville Parish, said Friday afternoon that he could not comment until he sees a copy of the suit.

"We don't now what court it was filed in. We don't know anything other than the news media reporting that a suit was filed," Breaux said.

The Iberville Parish has deployed the dams before on Manchac Road to prevent flooding from Bayou Manchac after floodwater rushed over that road into Iberville and over Alligator Bayou Road in next-door Ascension and then became trapped in the bowl-shaped swamp for weeks during the August 2016 flood.

Manchac and Alligator Bayou roads, which are different names for the same road along the southern boundary of Bayou Manchac, are elevated on a berm and serve as a kind of levee that can hold water in the swamp basin to the south with few outlets for water to drain. 

In 2016, parish leaders in Iberville and Ascension blamed floodwaters from East Baton Rouge Parish, which drains into Bayou Manchac along the north bank of the waterway at several points, for causing the flooding in Spanish Lake during the historic flood.

The parishes had to use pumps and cut the road in several places to get the water to drain out more quickly. 

Baton Rouge officials have criticized the use of the AquaDams as pushing floodwater on their parish.

Ourso said the dams are not being deployed but only be pulled out of storage and put in a location where they can be readily accessed. He said the dams have to be filled with bayou water and Manchac is low currently.

"I couldn't fill up a water balloon in Manchac right now," Ourso said.

Ascension Parish Councilwoman Teri Casso said Thursday that her parish's president, Kenny Matassa, agreed to close Alligator Bayou Road also to keep people off the road as the water rises.

She said the parish has HESCO baskets if necessary to block potential floodwater from pushing over Alligator Bayou Road.

For years, some officials in the various parishes had pushed for a regional plan that would control flooding in Bayou Manchac and Spanish Lake, but the parishes were unable to come to an agreement, scuttling chances for key permits from the U.S. Army Corps of Engineers.

Iberville and Ascension have made upgrades and expanded floodgates at Alligator and Frog bayous since the 2016 flood, and Ascension is still working on a key permit for a new floodgate planned at nearby Fish Bayou.

The gates are typically left open until water levels in Manchac reach a specified height and then shut to prevent more floodwater from pushing into the poorly drained swamp.

While residents of the two parishes live in the same larger swamp basin, Ascension residents are primarily affected by flooding in the Bluff Swamp, which is partially separated by old spoil banks from the parts of Spanish Lake in Iberville.

The Frog Bayou floodgate and the proposed floodgate at Fish Bayou drain Bluff Swamp. 

Email David J. Mitchell at dmitchell@theadvocate.com

Follow David J. Mitchell on Twitter, @NewsieDave.