When the developers of the Conway subdivision introduced themselves to Gonzales in 2015, they were proposing something new for the area — the kind of highly planned, old-school neighborhood made famous by them more than two decades ago in Lafayette's River Ranch.

With echoes of an old city neighborhood mixed with businesses and apartments, Conway's developers pitched their community as a step up from the norm in Ascension Parish, with prime access to Interstate 10 and either Baton Rouge or New Orleans.

The builders have made features out of the large live oaks on the former 344-acre cattle ranch and honed architectural details, but residents say Conway has a significant and unexpected problem now several years into construction: chronic street flooding that can linger for days after moderate rains and at one point blocked the neighborhood's entrance.

As parish officials search for a solution, the street flooding problem, which hasn't inundated any homes, highlights the difficulties the fast-growing region has had in using a mix of private and public drainage systems to allow continued home construction in flood-prone areas. 

Parish officials have pinned the blame on a 268-acre wetlands conservation bank north of I-10 from Conway and through which all the development's water must pass; conservation bank officials dispute the claim.

The problem drew local officials' and the developer's attention in 2020. By May 2021, after internal meetings with city and parish officials and the consultants and a new round of analysis, the builder, Southern Lifestyle Development, proposed to pay for a $1 million fix.

The developer would install new, automatic pumps to lower unexpectedly high detention ponds and allow the street flooding to drain, but the homeowners association would have to maintain them long term at a likely monthly fee of $5 per homeowner, a Gonzales city timeline says.

Ascension Parish doesn't allow neighborhood-level pumps but requires gravity flow from subdivisions to feed its huge regional pumps.

In an unprecedented move, parish government's eastern drainage panel granted a one-off waiver late last year, allowing the pumps under a highly conditioned deal with the developer.

Among those conditions, parish government required the city of Gonzales to take over the pumps if the homeowners association one day can't keep up with job. Gonzales, though it generally doesn't handle drainage, agreed.

Six months later, however, some residents have begun to question the wisdom of the pumps and their implications.

Some argue the pumps are simply a quick fix to a tough problem for the developer, which currently controls the homeowners association, so home construction can continue. Many others ask why they should bear the cost.

Glen Ourso, 72, a retired chemical industry manager who moved to Conway a few years ago, said he already pays drainage taxes to Ascension Parish, which handles most flood control work for the city.

"Why should additional taxes be imposed on us to pay for the operation and maintenance of the pumps," he asked. 

A change in position

Parish President Clint Cointment announced this month he wants to take another look at possible solutions.

He says Southern Lifestyle hasn't met all the terms of the agreement in any case; the city of Gonzales and the developer dispute that the terms of the deal haven't been met, except for a final agreement with Ascension.

Cointment's push to find a gravity-based solution is something of a shift from late last year when parish council members sitting on the drainage board waived their policy on pumps for Conway.

In November, parish administration officials faced questions from council members worried about departing from longstanding practice and setting a precedent that other builders could pursue.

Cointment and the parish's hired review engineer, Shaun Sherrow of CSRS, both told the panel then that pumps were the sole fix for this rare case, after review by at least three sets of engineers, and this case wouldn't open the door to pumps as the first option for drainage in other neighborhoods.

“I think the only way we see to solve the existing problems is a drainage pump situation," Sherrow told the council members on Nov. 14. "There’s no way around it, so we’re at that point.”

Though dirt work on new phases was happening last week, home construction in those phases has been put on hold, city officials said, while they and the developer wait for parish officials' new review of a possible fix.

"It's really their call," said Scot Byrd, the city's chief administrative officer. "They're the drainage people, so they have jurisdiction over that; so, from city's standpoint, we're just going to step back (and) wait and see what they decide they want to do. So, it's really between the developer and the drainage people now."

Jeff Vallee, director of development for Southern Lifestyle, said he welcomes the parish's efforts but believes conditions outside the neighborhood have changed for some reason, perhaps after the August 2016 flood, and only the pumps offer the best fix.

"We, as the developer, are committed to working to find a solution and have even proposed a solution on our dime … to remedy what we believe is an off-site problem," Vallee said.

Vallee noted the developer removed a beaver dam in a downstream waterway that was holding up water, but he said he doesn't believe other fixes will offer as much benefit as the pumps.

On Friday, Cointment said the parish would share more information when it has it.

"At this time, we are looking at all available options to help Conway subdivision with the street flooding during rain events," he said.

What happened?

For years, builders have used dirt fill in combination with man-made ponds in order to meet federal flood insurance standards for home elevations and to prevent new construction from flooding older, lower homes.

Dirt dug from ponds is used to raise homes on low-lying land. In general, the ponds temporarily hold rainfall from the new acres of hard surface streets, roofs and sidewalks, slowly releasing water over time and holding some high water from bayous and streams.

Conway, which is expected to have 826 single-family homes, plus apartment units, lofts and commercial sites, has four ponds, with six more proposed, plans and wetlands permits show. 

Despite their critical role in preventing flooding and occasional maintenance and design flaw problems, these kinds of neighborhood ponds remain the responsibility of dozens of homeowners associations in Ascension. The pumps at Conway would fall in the same category of infrastructure, parish officials say. 

For this kind of passive, gravity-based system to work properly, however, engineers must assess how high water in the bayous and streams that receive the pond runoff are, on average, to set a correct height for the ponds' outlet pipes. 

As it turns out at Conway, the original 2015 engineering set the outlet pipes too low for today's conditions, a 2023 reanalysis has found. The average water height in the main discharge canal for the neighborhood is 3 feet higher than engineers had originally estimated.  

Water is backing up into the detention ponds, leaving them higher than they were designed to be and, as a result, with less storage capacity than planned to handle neighborhood runoff. 

'How was this not caught?'

Though parish government backed Conway's original drainage study, the developer's analysis failed to look much beyond the property's northern boundaries at I-10, the study shows, nor examine what role the manmade creation of a swamp to the north could play in draining Conway.

The U.S. Army Corps of Engineers approved the wetlands bank, known as Bayou Conway Mitigation Bank, and construction began in 2011 and 2012, three to four years before the Conway neighborhood drainage study was completed. 

"My question is: how was that not caught," Conway resident Glyn Hays, 43, asked the drainage board earlier this month. "Why was there no investigation into that plan to say, 'Wait a minute. This doesn't work. If it's going to be blocked by this (land bank) … what is essentially a dam, from what I can see, why was that not caught? Why was it allowed to continue? Why were we sold houses in the neighborhood?"

Officials at Delta Land Services, which owns the Bayou Conway bank, said they didn't know their land bank was being blamed for the high water until contacted by a reporter earlier this month and hadn't then talked to parish officials about their theories on the flooding.

Paul Bergeron, land manager for Delta Land, said he agrees the water is higher for some reason but argued the bank is probably helping things because it retains water.

He said the bank will work with the parish if needed but disputed the land bank has anything to do with Conway's problems, saying the bank was approved and planted its trees years beforehand.

"All of that was done several years before the developer bought the property," Bergeron said.

Corps of Engineers officials noted the same difference in time between the land bank's and Conway's development but weren't immediately able to provide more information about what their analyses of the land bank and Conway considered.

For now, residents in Conway await a resolution. One of them, Charles Boudreaux, who objected to the pump deal's conditions, noted he previously lived in St. Charles Parish for 65 years. It's relied on pumps to keep people dry.

"So, it is doable if it's necessary, but I like the idea of trying to find some other solutions to this, if there are other solutions," he said. 

David J. Mitchell can be reached at dmitchell@theadvocate.com or followed on Twitter at @newsiedave.