GONZALES — Facing public pressure to address the effects of the August 2016 flood, the Ascension Parish Council will expand limits on the use of dirt to raise homes in the parish's lowest areas while also requiring that homes and businesses be built a foot higher than they already must be.

The changes represent a tightening down of how builders can construct homes and businesses in a parish where more 70% of the land is in the most high risk area for flooding and where the August 2016 flood inundated swaths of homes subject to backwater flooding in the Amite River Basin.

The major expansion of the parish's current, far more restrained limit on the use of dirt, or fill, will now apply to most forms of development in the 100-year and 500-year flood plains and comes as Livingston Parish is also considering similar kinds of limits in reaction of the same set of pressures over the flood.

"We made a big step tonight," Ascension Councilman Bill Dawson said after key council votes Thursday night in Gonzales. 

The upshot of the new changes -- a tougher version of the recommendations from HNTB, an engineering firm hired after the flood to look at the parish's drainage and construction rules -- is that more homes and businesses in Ascension will have to be elevated without solely using dirt and must also be built even higher than they do now.

For many years, developers used dirt without limit to raise homes to meet parish elevation rules in large-scale commercial and residential projects but had to built detention ponds to counteract the water displacement caused by all that fill.

Even before the 2016 flood, but especially afterward, that practice of "fill mitigation" drew the ire of longtime residents who watched low-lying pastures that once held water get built up several feet next to them and were skeptical of engineering showing detention ponds would protect their homes, too. They argued mounding up dirt is like dropping one more ice cube in an already-full glass. There's no place else for the water to go but into someone else's house.

"Something does need to be done with development, and it needs to be not in favor of the developers," Linley Brown, 73, a 13-year resident of Quail Creek neighborhood in Prairieville, told a group of parish officials at a public hearing last month about the proposed changes that are now law.

Pier-and-beam, chain wall or other methods of construction recalling Louisiana's roots in elevated building are now expected to become more prevalent and necessary in large parts of Ascension. The prospect of that change and the added costs tied to it brought opposition from builders worried they make it harder and more expensive to build in the parish.

Quiet for months over the past year as the proposal lingered before the council and its drainage board, builders showed up in force in recent weeks in meetings to oppose the plans as a wrongheaded, blanket change without factual support that would have unintended consequences and still not prevent another flood of the same magnitude.

They also seized on the admission of the parish's own engineers who acknowledged a few months ago that the proposed expansion of the limit for fill had no scientific background but simply broadened rules in parish ordinance that originally resulted a political compromise several years ago.

"Too many questions, not enough answers. Let's not make a poor decision just to say we made one," Nathan Spicer, 52, a local builder, told the council Thursday. 

The new law sets an across-the-board, 3-foot-deep limit on the amount of dirt that can be used to raise homes and businesses inside the 100-year and 500-year flood plains. The flood plains are used by the National Flood Insurance Program to define benchmark, hypothesized floods and establish risk for insurance purposes.

Even with the new limit on the depth of fill, builders will have mitigate the use of that dirt with detention ponds or other methods for all new building, except for single-lot construction on land covering two acres or less.

Perhaps more significantly, the changes also require that structures now have two feet of space, or free board, above the projected height of a 100-year flood. Known as the base flood elevation, the projected height of the 100-year flood is a bench mark the NFIP uses on its flood risk maps to show how high new homes and businesses must be at a minimum.

Ascension's new requirement represents a one foot increase over the parish's old one-foot free board standard. Citing NFIP's own data, supporters suggested the change would halve flood insurance rates for new homes and gear parish development for the long term. Critics argued the change would continue to push homes higher, raising them even farther above their older counterparts next door.

Builders like Spicer, Shane Marler and others have argued the changes will set loose cascading effects on home construction, raising the cost but, due to market preferences for slab homes, not reward that added investment with higher home values. 

"If you can't go higher than ... 3 foot and your property's majority 4 foot low, it's not that you're going overvalue that property. Nobody's probably going to fool with it, which means nobody's going to want to buy it because you can't do anything with it," developer Frank Fudesco told parish officials at the April public hearing. "And if you can or you attempt to, there's so many unknowns of what it applies to, who it's going to apply to, what building it's going to apply to."

Spicer offered estimates of $8,000 to $15,000 extra for a home on piers. But some parish council members brushed off concerns that the new rules could knock Ascension, with the lure of its public schools, off its current population trend as the state's fastest growing parish in 2018. Council members noted developers aired similar dire warnings in years past about road impact fees and other development measures.

Councilman Daniel "Doc" Satterlee cited his own experience and the peace of mind he gained from raising a second home in Slidell, as well as the high value of other homes elevated in his St. Tammany Parish neighborhood near Lake Pontchartrain.

"I kind of say poppycock to all of this," he said. 

Earlier versions of the new ordinance had applied the fill limits only inside the 100-year floodplain, an important threshold in NFIP's flood risk scheme. Homes below the height of the 100-year flood and with a bank mortgage must get flood insurance. A 100-year flood has a 1 percent chance of happening in a given year. 

But the addition of the 500-year flood plain, which has a 0.2 percent chance of happening in any year, likely will expand the land area where the new fill limits will apply, though when this change actually takes effect is unclear. In Ascension, the 500-year flood plain has only been defined in a small area. So, the fill limit won't take effect outside the 100-year flood plain in most places until the federal government upgrades flood risk maps, parish officials said.

That change and the free board alteration were part of package of amendments brought by Dawson and others. Councilmen Dempsey Lambert and Todd Lambert tried Thursday through two amendments to cut the one-foot increase in free board, expand a grandfather clause for existing construction from 30 to 60 days and expand an existing exception to fill mitigation requirements to two-acre lots. The changes were aimed aiding residents wanting to build homes in the parish's more rural areas.

Another amendment from Councilman Aaron Lawler put the free board change back in but left the grandfather clause and mitigation exception. That amendment narrowly passed, 6-4, and negated the competing amendment from the other councilmen. The final, combined proposal was adopted without opposition.

Councilman Todd Lambert said while he didn't get everything he pushed for, the council needed to act.

"We gotta get it going," Lambert said of the new rules. "I mean it's a living document. You know we can change it (if needed)."

Follow David J. Mitchell on Twitter, @NewsieDave.