DONALDSONVILLE — More than three years removed from the August 2016 flood, Ascension Parish has taken an important step to limit the potential for future flooding connected with new development. In so doing, it sought to balance the concerns of angry residents demanding action, builders worried that tougher rules would make new housing too expensive and a parish president who vetoed an earlier stab at a fix.

The changes, which were approved Thursday night, attack how builders pile up dirt to raise slab homes in a parish where more than 70% of the land is deemed at high risk of flooding. The new rules set across-the-board limits and force homes and buildings to be built higher than in the past.

The action taken by the Ascension Parish Council means that in the lowest parts of the parish that are most at risk for flooding, builders may not be able to use dirt fill entirely to elevate new homes and other buildings. Instead, they would need to use a combination of dirt and pier-and-beam or chain-wall construction to meet federally inspired elevation rules in Ascension.

Pier-and-beam homes would mimic more traditional, south Louisiana-style homes with wooden slabs that rest on cinder block or concrete piers. Chain-wall construction often involves the use of concrete walls tracing the perimeter of a building to form its foundation.

The new rules will also require the private owners of neighborhood and commercial detention ponds — key flood mitigation features in projects that use dirt fill — to undergo five-year inspections and make necessary maintenance or potentially face fines. Historically, in subdivisions, homeowners associations — not the parish — are left the responsibility for such ponds after developers finish construction.

The amendments come after the historic flood that sent water into more than 6,200 homes in Ascension and led to renewed criticism that the fast-growing parish's past practices with dirt fill were worsening the flooding of older, lower homes.

Even as some council members in 2017 threatened a moratorium on fill, the parish hired engineering firm HNTB to review parish ordinances. The company soon came up with the outlines of the changes. The administration and council, however, didn't get around to considering an actual ordinance until this spring.

The newly adopted changes coincide with Parish Council elections this fall in which drainage and other infrastructure impacts from growth have become major issues.

"I'm glad that that passed, but there are some more needs. I guess one step at a time," Cindy Steyer, 61, a Prairieville resident who flooded in 2016 and was initially opposed to the plan, said after the Parish Council adopted the new requirements Thursday night. 

The final version of the new rules was developed by an administrative revision committee, which included five council members appointed by Parish President Kenny Matassa. The committee was created after Matassa vetoed an earlier version of the ordinance. The committee met in secret throughout the summer to reach a compromise. Builders, outside groups, as well as individual council members, criticized the closed process.

On Thursday, Matassa thanked the five council members who worked on that committee for the new ordinance, which he described as a "living document." Future changes could include barring the use of fill in the parish's coastal zone, a priority of Matassa's. He said that limit was left out because it needed more work.

"This won't be the end of it. It's just the start," Matassa said  

Also left unresolved is whether to apply the new inspection and maintenance requirements to existing detention ponds. Instead, after considerable debate, the council set a 120-day deadline for the administration to come up with answers.

Despite the long fight between Matassa and the council, the new rules are similar in key ways to the vetoed ordinance from May.

The new rules limit the amount of dirt fill to 3 feet deep across the parish and also set the minimum height of the bottom floor of new homes and other buildings so that they must now be 1 foot higher than what was most currently mandated in Ascension.

The new rules also increase from 1 to 2 feet how high homes need to be built above the projected height of the 100-year flood, what's known as the base flood elevation. A 100-year flood has a 1 percent chance of happening in any given year.

What that means is in the lowest areas, builders will have to find a way to elevate homes higher than they had to before. But, in combination with the new limits on fill, builders won't be able to reach that new height, in some cases, with dirt alone.

Also, even with the new across-the-board limits on fill, builders must counteract the flooding impact of dirt fill that they do use inside the 100-year floodplain. That typically would take the form of building additional detention ponds to temporarily hold rain and flood water.

The federal government has defined as the 100-year floodplain as an area at high risk for flooding. Homes in the floodplain with a mortgage must have flood insurance under existing requirements of the National Flood Insurance Program.

Both the old parish rules and the vetoed attempt to revise those rules in May exempted owners of smaller, individual lots from having to counteract the flooding impact of their use of dirt. The new rules eliminate those exemptions.

Kimberly Koehl, an engineer with GSA Consulting Engineers, which was hired to help the committee, said language clarifications and the elimination of those exemptions were some of the biggest changes from the vetoed ordinance.

"It's a lot easier to read, and it's applied evenly from individual lots to subdivisions," Koehl said. 

Another change from the failed May ordinance is that there needs to be more consideration and spacing for ditches, waterways and neighboring properties when fill is used to elevate land.

And the new rules eliminate language that would have extended mitigation requirements across areas at lower risk for flooding, in part, because those areas in Ascension have not been defined by the federal government. Builders, Matassa and his building department objected heavily to that requirement in the failed May ordinance. 

The Parish Council adopted the changes unanimously Thursday, but some council members excluded from the closed-door group that developed them remained unhappy. A sixth council member on the committee would have constituted a quorum and required open meetings.

Councilman Daniel "Doc" Satterlee claimed the committee's meetings were illegal and said he would like a legal opinion to examine that question. He said the parish's lawyers have said it is legal because the committee is administrative.

"The result we adopted tonight is a good document, and yet I still have concerns about fact that we had a committee that didn't meet in the open and then came up with this. We are supposed to be a deliberative democracy that operates in the light," added Councilman Bill Dawson.

He said he was worried the council would be setting a precedent for the future.

Besides elected officials, groups on various sides of the fill issue also said they were cut out of the process, including builders and advocates for the Lake Pontchartrain basin.

Nathan Spicer, a builder who has said pier-and-beam construction would increase the cost of homes by more than $20,000 each, said his industry was invited to one meeting of the revisions committee and never got a return invite.

"We have reached out numerous times to various stakeholders, specifically the engineers drafting this ordinance, for answers, but have received little-to-no response," Spicer wrote in an email late last month. "Like our fellow residents, we have been left largely out of the conversation."

Speaking before the council Thursday night, Spicer didn't raise those concerns again but said that he hoped one day the parish would have the money to do the technical work to see if the new fill limits are scientifically supported. But he also acknowledged the parish had to act and start somewhere.

Polly Glover, a Prairieville resident who lives along Bayou Manchac and serves on the Coalition to Restore Coastal Louisiana's board of directors, said the parish didn't respond to hers and others requests to include the Lake Pontchartrain Basin Foundation. The New Orleans-area environmental group looks out for the health of the basin that includes Lake Maurepas and part of Ascension.

"It's easier for me to go down the Legislature and lobby for coastal restoration funds than it is deal with this parish. That's a pretty pathetic situation," Glover said in an interview.

Email David J. Mitchell at dmitchell@theadvocate.com

Follow David J. Mitchell on Twitter, @NewsieDave.