What did we get from millions spent on drainage? We don’t know

Aerial of Homewood detention pond
LCG has spent millions of dollars on drainage projects since 2016, but local rules don't require it to determine how much that work is really worth. Photo by Robin May

Lafayette has spent hundreds of millions of dollars on drainage in the aftermath of the devastating flooding of August 2016, but there’s been little accounting of how much that has reduced the community’s flood risk.

Lafayette Consolidated Government has cleared miles of coulees and ditches and poured tens of millions of dollars into detention ponds, but the overall impact is unknown, primarily because Lafayette has not assessed whether this work will prevent homes and businesses from flooding.

Lafayette’s local rules don’t require a formal cost-benefit analysis to be conducted or published before LCG embarks on drainage projects. Instead, the mayor-president has discretion to pursue any project without much stipulation, as long as the councils fund it.

That’s a problem for a community trying to balance its need for growth against increasing flood risks, and it leaves little room for residents, or even council members, to determine whether taxpayer funds are being put to good use. By comparison, Congress has required the U.S. Army Corps of Engineers to formally report projects’ costs and benefits since at least 1936.

Requiring formal cost-benefit analyses for larger projects is a practice Lafayette should embrace to give residents a better understanding of their flood risk and to make sure those projects are having impacts that justify their costs, says hydrologist and retired UL civil engineering professor Mike Waldon.

“That can give you an idea of, say, if we spend $100 million on a project, and it looks like it’s going to project $10 million worth of property, you probably would have been better off to just go buy that property and change it to a park so you didn’t care if it flooded,” says Waldon. “That kind of cost analysis and risk analysis, as far as I know, has never been done in Lafayette. And it's a pretty standard thing.”

Mayor-President Josh Guillory’s $108 million Bayou Vermilion Flood Control Project is a clear example. The project, which includes the enormous Homewood Drive detention ponds, was launched in December 2021 as an $81 million, multi-site endeavor along the Vermilion River and Coulee Ile Des Cannes west of the city limits.

While modeling suggests the project will have some impact on nearby flooding, LCG has never produced a report on how many homes it will benefit in any given strength of storm despite having the project’s engineer produce multiple reports on its efficacy before breaking ground.

Instead, as the project’s cost has ballooned, LCG has only pointed to the number of homes on the Vermilion that flooded in 2016 for justification without saying how many the project will affect.

Contrast that with the Corps’ 2020 study of dredging the Vermilion River. Separate models suggest the two projects would have a similar impact on the river in a 2016-style storm, but the Corps effectively canned the dredging after preliminary analysis found it would only save some 200 homes and cost up to $150 million.

That calculation, if it was done for BVFC, hasn’t been released despite public records requests, a City Council investigation and a lengthy lawsuit. The same is true for LCG’s $4 million clandestine removal of the Vermilion River spoil banks in St. Martin Parish.

That level of analysis could be burdensome for smaller projects, says former LCG Public Works Director Kevin Blanchard, since Lafayette is still waiting for a regional watershed model to be released later this year. But for larger projects, a local cost-benefit analysis requirement is needed to protect the community’s trust in local government and ensure tax dollars are having a substantial impact.

“Without the ability to very finely quantify, on a regional basis, what the actual impact was for a project, you can't tell [people] that 500 homes flooded in this event, but had we not done X, Y, and Z projects, it would have been 1,500 homes that flooded,” says Blanchard. “If you can’t tell people that, then ultimately … I don’t know that people are going to truly understand why it was that we did any of this.”

Even as Lafayette’s drainage efforts leave the question of what the community has gotten for its money unanswered, the parish’s exposure to flood risk is getting worse.

Detention requirements in Lafayette’s development code make it more appealing to grow in vacant areas where land is more prone to flooding, even if that flood risk is less apparent.

Aerial of Homewood detention pond
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Flooding

Flooding and drainage are major political issues in Lafayette every election year. Read more about how LCG impacts it here.

Lafayette’s detention regulations are calibrated for new developments in vacant areas, but they impose the same requirements on urban development in existing parts of the city that are less prone to flooding.

That creates a perverse incentive to build in low-lying areas where land is available for detention ponds, since that’s less expensive than redeveloping existing areas to hold stormwater, usually through costly underground detention chambers.

That created a steep burden for a recent project on Amaryllis Drive in Lafayette, says Billeaud Companies President Steven Hebert, who serves on the city’s volunteer Planning & Zoning Commission.

“We bought a house that was burned down, tore it down and built four townhouses. We spent $125,000 before we poured the slab,” he says. “We had to detain stormwater on a 100-by-150 [foot] lot that had a house on it with a driveway that was shedding water. And that water was going straight into the drainage system.

“I’m not sure we had the impact on the drainage system on that little 100-by-150 [foot] lot that we increased the watershed all that much,” he adds. “But with that kind of thing, they tell you that you have to do it, and you just have to do it.”

The result is that Lafayette’s detention regulations effectively promote growth in undeveloped areas, particularly for affordable housing, at the cost of its flood control efforts.

“Those two things work against each other,” says Hebert. “They are in conflict. … It’s just a fact of life. A developer has to do more now than they did before the changes made after 2016. And they have to use more land.”

That is undoing Lafayette’s progress in combating flood risk, since protecting more land is generally a greater burden, regardless of whether that land is more or less prone to flooding, says Waldon.

“Even if those areas are no more likely to flood than some area that's really compact in the city, it's going to be a lot easier to do flood management and reduce flood risk if the houses are in a tight pattern rather than when everything's just sprawled out,” he says.

Ultimately, Lafayette’s growth into undeveloped areas and its lack of analysis for its flood control projects have caused the parish’s flood risk to grow without clear answers for how safe its communities are from flooding. Both factors come down to decision making in local government, where Blanchard says public trust is critical to getting support for changes that could address the parish’s flood risk. “I think a lot about this stuff in the context of public trust, because without the trust of the public and their buy-in, it's very difficult for the government to do anything. That's like a commodity. You can waste it. You can lose it,” he says.

“I just really worry that the next big flood… [or] the next time there's multiple people who get water in their homes because of an afternoon flood event, people are going to say none of this was worthwhile,” Blanchard says. “Like, there's just going to be so little trust, because we haven't really communicated very well with people about what it is we're doing and why.”