Don’t panic: There is no flooding ‘silver bullet’

Bridge going over a river

It was the congressman’s job to break the bad news. At a briefing with researchers just before he took to the press conference podium last week, U.S. Rep. Clay Higgins was told what he didn’t want to hear: dredging the Vermilion River would cost a lot of money and not accomplish very much, relatively speaking. A political figure, he would be in charge of pouring cold water on a political movement that had carried the idea of dredging the Vermilion to bumper sticker status. Virtually every candidate in Lafayette’s 2019 elections got behind it in some measure. Lafayette Consolidated Government put $5 million aside for a future downpayment. The public waited for the study to be released and for the would-be solution to be greenlit. Chastened, Higgins slowly got to the point. 

“I was of the opinion, quite frankly, that there’d be greater impact, greater performance out of the river if you restored it to its intended parameters,” he said at the presser. “We’re seeing that dredging the Vermilion to its fully intended parameters is not the silver bullet that we thought it would be.” 

His announcement was based on a study commissioned by the U.S. Army Corps of Engineers and intended to settle on scientific bonafides, care of a model created by UL’s Watershed Flood Center, what had become an emotional plea and a political tug of war between leadership in Lafayette Parish and Vermilion Parish. Higgins played shield to scientific opinion. 

“We determined that science would have to be the solid foundation on which we stand,” he said. 

The Corps of Engineers has not formally killed dredging altogether, but the message conveyed is clear. At a projected cost of $150 million dollars, restoring the river to historically authorized depths would have spared 175 homes from water in the no-name floods of August 2016. Some 7,000 structures in four Acadiana parishes were flooded in that event. Even a partial dredging scenario — so-called “spot dredging” to clear out mounds of silt and debris along the river’s bottom in city limits — wouldn’t deliver the hoped-for effect. Cost-benefit ratios are often tragic for the individual as they protect the common good. 

Of course, dredging the Vermilion is not a silver bullet because there is no silver bullet, according to researchers and engineers. Even Dave Dixon, who leads Dredge the Vermilion Inc., a nonprofit founded to advocate for watershed solutions, couched it as but one on a laundry list of projects he believes is needed to rein in an overwhelmed Teche Vermilion watershed, albeit the central and organizing concept. Dixon and his partner Harold Schoeffler, who heads the local Sierra Club chapter, have spearheaded the dredging movement. Through its own efforts, Higgins’ office in turn elevated Dredge the Vermilion’s work. 

“I agree with the comment that there’s no silver bullet or magic solution to the problem,” Dixon says, arguing that a comprehensive solution needs to start at the river’s headwaters in the north and work downward, digging out shoals and manipulating flood control structures that have grasped at managing water in the region for decades. Dredge the Vermilion won’t stop advocating for its namesake; Dixon and Schoeffler remain skeptical of the Corps’ cost estimates and data. They will host a public meeting in March to gather more public input. 

“The bottom line is I think they don’t want to do this project,” Dixon says. “Because there’s opposition in Vermilion Parish, so they throw an astronomical number out there” in estimating the cost. “That’s my suspicion,” he says. 

While the dispute will linger in the political sphere, how to manage water is not without some consensus, at least broadly. The principles of the problem are largely agreed upon: Some combination of intensifying rains and sprawling development throughout Lafayette Parish and beyond has overwhelmed the natural and manmade channels that move water into the Vermilion. It’s there that dredging makes intuitive sense: Unclog the ditch and the water will run its course. 

A gif showing land cover growth in Lafayette Parish between 2001 and 2016. Development plays a big role in the amount of water gushed into drainage channels and, ultimately, the Vermilion River. Data by National Land Cover Database.

Similarly, researchers, engineers and stakeholders agree on the outline of a solution. There’s too much water moving too quickly, so something must be done to slow it down. 

While Dixon and citizen activists question the Corps study, many of their observations match up with the model built by UL’s researchers. The major channels that feed water to the Vermilion are dangerously synchronized, pumping rapids of water into the river at the same time during big storms. The trick, maybe, is knocking those channels out of sync. 

For civil engineers, the basic tools for that task are detention and retention. Youngsville city engineer Pamela Granger, an informal adviser to Dredge the Vermilion, has pushed the bedroom community, hard hit in 2016, to invest in retention. After 2016, Youngsville adopted the strictest drainage regulations in the parish, requiring developers to hold water for 25-year rain events, larger storm requirements than mandated by the Unified Development Code, which governs land use and development standards for the city of Lafayette and unincorporated areas of the parish. Mayor-President Josh Guillory has called for the UDC to upended and replaced with more developer-friendly regulations. 

Granger reviewed detention ponds holding water for eight of the worst affected neighborhoods in the city and retrofitted them to buffer against bigger storms and stop backflow from channels downstream. Youngsville has two major retention projects in the works, totaling 65 acres at $10 million. She calls it a four-pronged approach: detention, maintenance, capital improvements and higher development standards.  

“You clean coulees, you clean channels, and you increase your development standards so in the future it doesn’t get worse,” she says. Has it worked? Anecdotally, Granger points to the June rain bomb that flooded homes in 2019, mostly inside Lafayette city limits. Youngsville took on enough water to flood many of the same homes soaked in 2016, according to several rain gauges she deployed, and yet they didn’t flood this time around. 

Waters reached 11 feet inside the Downtown underpass during a June 2019 downpour. A woman safely escaped a car stalled at the bottom of the dip. The downpour was a “climate signal” of intensifying rains, said meteorologist Rob Perillo.

These are still microcosms of a much larger problem affecting the entire watershed. Emad Habib, a professor in UL’s College of Engineering and the head of the Louisiana Watershed Flood Center, vouches for the basic principles expressed in Granger’s approach in Youngsville. Over the last two years, Habib’s team built the watershed model that the Corps’s dredging study is based on. Arguably, the data-first approach has worked. Running the dredging scenarios, the model was able to confirm what many civil engineers already suspected, that dredging wouldn’t do the trick. But the model works the other way, too. It can theorize solutions too costly to build or implement on speculation.  

“This is now a scientific tool that can answer some of these questions,” Habib says. “It’s not going to be just one thing. It’s going to be many things [that address the problem]. It’s the cumulative benefits of these projects.” 

One idea teased out in the UL model is the role played by Cypress Island Swamp. Habib’s research suggests the swamp could act as a natural reservoir to control flows to the Vermilion from major channels like Coulee Ile Des Cannes, which is being widened by the city of Scott. Dixon reached a similar conclusion, suggesting that removing banks of dirt that block flow to the swamp could provide a much-needed outlet into a 28,000-acre reservoir. Dredge the Vermilion submitted the spoil removal project to the Louisiana Watershed Initiative, a state program in charge of a $1.2 billion federal grant formally authorized this year, for consideration. LWI broke out $100 million for “no-regrets” projects that can be done without modeling. The project is estimated to cost about $1.7 million, but could be ensnared in a competitive grant process. 

“The problem is it’s competing with 300 or 400 projects. The competition is going to be fierce for that money,” Dixon says.

All things land back in the realm of politics. LWI was created by the state to float stormwater management above the political fray and avoid petty squabbling over project dollars. The initiative created eight regional committees, roughly drawn from each watershed in the state, and charged regional planning commissions with convening leaders from the parishes that comprise each region. It’s at this level that big strategies could be devised to address what’s historically been a problem managed by competing jurisdictions. If successful, LWI could codify regulations and best practices and fund large-scale projects that coordinate how communities live with water. 

Politics, it seems, is unavoidable. And the urge local leaders have to respond to immediate needs and desires, at the cost of long-term risk, could be tricky to overcome. 

Dixon and others, including some local officials, have criticized what they regard as a piecemeal approach already underway in Lafayette Parish. But Dredge the Vermilion takes particular aim at the widening of Coulee Ile Des Cannes, for instance, a project they believe will exacerbate the problems downriver on the Vermilion. Meanwhile, Scott Mayor Jan-Scott Richard beamed to The Daily Advertiser that the project would pull land out of floodplain designation and open it up for more development. Dixon has approached Mayor-President Guillory about delaying the project. Guillory signaled support for his request, according to Dixon. The administration did not respond to requests for comment as of press time.

Both UL’s Habib and Youngsville’s Granger sit on the 19-person LWI steering committee, along with Teche-Vermilion Water District Executive Director Donald Sagrera. The other 16 seats are held by appointees of each parish in the Region 5 watershed. Drafting the steering committee’s bylaws last week, the committee excluded Habib, Granger and Sagrera — all community appointees — from voting on committee decisions in the future. One parish, one vote, is the logic.  

“Water knows no boundaries” has become the operating cliché. But local leaders are jealous of the authority and protective of their projects. Still, there is some optimism that data can buoy common sense to prevail over political differences. 

“This is not rocket science,” Habib says of the blocking and tackling of managing water. “People will agree on it.”