Ascension eyes moratorium on certain kinds of housing development – The Advocate

GONZALESFor years in Ascension Parish, individual homes and sometimes entire subdivisions have been built on mounded dirt in flood-prone areas to raise them out of harm's way.

After 6,400 homes and businesses in the parish were swamped in August, many flood victims are casting a jaundiced eye toward the practice, blaming it for forcing water into their houses or onto their property.

Now, despite arguments by developers that science supports the current rules, the Parish Council is set to consider temporary restrictions on the large-scale use of dirt to elevate subdivisions in the growing parish. If approved, this moratorium would be in place until a new analysis of parish flood plains is completed and new rules can be developed to better protect against future flooding.

Two Prairieville council members, Aaron Lawler and Daniel "Doc" Satterlee, proposed a blanket halt on fill earlier this month and pushed it out of committee on a 2-1 vote with some members absent. But the move to restrict use of fill could end up becoming more narrowly tailored to major developments when the council takes up the issue in June, Lawler said.

Lawler said the August flood has raised anew longstanding questions about whether parish fill practices are inadvertently worsening flooding, as critics have charged for years.

"I think you have a lot of councilmen that it was brought to the forefront for them because of the flood. Their opinions on it may have changed when they saw how bad that flood was, so now there is support for this," Lawler said. The proposal would not be retroactive.

He said he'd like to see the new flood management plan start looking at homes in the lowest areas to elevate with pier-and-beam construction, instead of slab foundations.

Though estimates for Ascension Parish still being refined, the U.S. Geological Survey found the August flood fell between a 100- and 500-year event, or an event that had a 1 percent to 0.2 percent chance of occurring in a given year. With that large of an event, much of Ascension's public and private drainage infrastructure in the path of the flood was overwhelmed by the water because it exceeded the designed capacity.

Parish officials say the flood plain review on which the moratorium would hinge could take up to eight months. Lawler thinks it could be done over the summer months when new development proposals normally slow. With the review, the parish would hire an engineering firm to take a close look at drainage issues in each of the parish's various floodplains so new drainage and other development rules can specifically be catered to each one.

While officials in support of the moratorium emphasize they aren't specifically blocking particular subdivisions, some in the construction community said the proposed fill limitations will effectively halt future projects because it is impractical to build any other way.

"It'd pretty much shut it down," said Jared "Burger" Beiriger, vice president of construction and inspection for Quality Engineering and Surveying, one of the primary engineering firms at work in Ascension's residential home market.

Despite potential economic impacts, what's driving the moratorium are the complaints of longstanding parish residents like Duane Simpson, 47, who survived the flood and are fearful of new subdivisions with large amounts of fill.

These residents are skeptical of claims from developers and parish consulting engineers who say that through standard engineering principles they can ensure new projects won't flood their neighbors.

Simpson, whose family has lived in the Galvez area of northeast Ascension since the 1800s, recently scoffed at that idea. He said it defies his experience of what water does when it hits hard clay and concrete and starts running off a steep slope of mounded dirt.

"We got to use common sense. Somebody somewhere's got to use common sense," he said.

As in other surrounding parishes, Ascension doesn't allow builders to construct new homes with ground floors below the level that water is estimated to reach in a 1 percent-chance flood. Ascension requires ground floors be 1 foot above that projected water level, which is also known as the base flood elevation.

Estimated by the Federal Emergency Management Agency, base flood elevations are used in flood hazard maps. The elevations help set benchmarks for federal insurance rates and are used in local building rules.

An upgrade in Ascension's flood maps in 2007 led to significantly higher base flood elevations across the lowest parts of the parish. That change, in combination with development rules, has led to large, newer developments that are meeting elevation requirements with fill that can push them several feet higher than older homes.

Simpson, his family and his neighbors successfully fought the 32-home Hudson Cove subdivision proposed in April next-door to his dad's 5.25-acre home south of La. 42 and Bayou Manchac.

Pointing to the severe flooding that hit their area in August, they aired worries that the new subdivision would have built up a low-lying drainage area that held a lot of water during the flood. Simpson'sfather's house, which is elevated 43 inches off the ground and well over the old high water mark, avoided flooding by inches.

Despite an engineering report from the developer to the contrary and the parish staff's determination that Hudson Cove had met parish drainage requirements, the Planning Commission heeded the residents' concerns.

"My reason is for the drainage," Commissioner Wade Schexnaydre said in explaining his motion to deny during the spring meeting."I believe we are going to succumb to even more issues. I understand what the hydrology and drainage study says, but existing records are already showing that we would be pushing it too much." The motion to deny passed 2-1 with one abstention.

Developers and the engineers who work for them say the public and some on the council misunderstand basic hydrology and what the fill rules require.

Under parish fill and drainage requirements, new projects cannot worsen the drainage of their neighbors. For major subdivisions, developers must conduct drainage studies that determine where and at what rate water is running off an existing site and estimate how much more will run off after development.

Based on that estimate, developers must calculate what kind of detention is needed so the extra water isn't pushed on neighbors. In areas below the 100-year floodplain, these calculations must account for not only rainfall but also lost flood capacity from filling land up to the height of the 100-year floodplain, parish officials said.

Under parish rules, developers also cannot import dirt to a site in the floodplain, but must instead dig out dirt on the site to build up the property.

In the cavities from which the dirt had been taken, detention ponds are created to hold future rainfall runoff and flood water and release it downstream at a rate that is no greater than it was before homes were built.

Engineer Mickey Robertson, owner of MR Engineering and Surveying, said what developers are doing is replacing "air with dirt and dirt with air, so if you had a certain amount of storage volume before development, you have exactly the same storage volume after development."

He contended this one-for-one "volume swap" means more water isn't being pushed on other people's homes by fill because no extra earth is being added to the site.

"Nobody understands it. Nobody believes it, but that's the reality of it," said Robertson, who did the engineering for the 195-home Hollows at Dutchtown subdivision near I-10 and La. 73 a few years ago and says it has improved drainage in the area.

Joseph Guillory, a civil engineer with Duplantis Design Group in Covington, said the type of mitigation Ascension uses is common in Louisiana and elsewhere in nation and does work in an ideal situation.

Guillory said detention ponds don't eliminate the increased volume of water that runs off a developed piece of land, but slows down and stretches out the flow of all that extra water downstream so there is supposed to be no greater impact to neighboring properties.

But he said Louisiana's low, flat topography and the tidal influences on major drainage storage areas where most runoff ends up can cause back-ups during big storms.

"If (the big storage area) gets full and the water can't flow, what happens to all that water that's coming downstream? It goes out of bank, and when it goes out of bank, it starts flooding things. That's the problem," Guillory said.

He also added that different statistical methods can result in significantly different estimates for how much runoff is generated by development, a crucial early calculation that helps determine a new housing subdivision's drainage systems.

His colleague, engineer Tommy Buckel, said some communities are looking at buying land for regional detention areas to help handle the extra water and having developments help chip in for the cost, which can be expensive.

Ascension Public Works Director Bill Roux said the administration is still weighing its position on the developing moratorium proposal. He said that if it is aimed at subdivisions, the moratorium would halt development that already has its drainage impacts mitigated. He argued that continuing to allow single-lot construction with fill under the proposed moratorium ignores one of the bigger drainage culprits.

"The part of the parish that is totally unregulated for the most part is the individual houses," Roux said, adding landowners can also bring in fill from outside their properties.

Homeowners like Michael Latiolais, 50, of Prairieville, who spoke recently in support of the moratorium, said the 3 feet of fill directly under his house saved him from flooding in August. Water backing up from the Muddy Creek cutoff ditch was three inches from his home near a fast-growing area off La. 930.

He doubts the little bit of dirt he dug from his pond and put on his 2.5 acres has much effect on anyone else. But Latiolais said his flooding troubles are from the subdivision behind his house that is draining water across his and his neighbors' land.

"The solution is stop, stop until the municipalities catch up, stop until Bill Roux can get caught up," Latiolais said.

Can't see the video below? Click here.

Taking note of Roux's critique, Lawler acknowledged that his new proposed moratorium is a political compromise that would include an exceptionfor up to 1 foot of fill and for residents who flooded to restore their homes as they were.

But Lawler said his intent is that the limited amount of allowable fill would effectively only permit new construction of individual homes and mobile or manufactured homes, but still block new larger housing tracts and other big new developments that would likely need more fill than 1 foot of dirt.

While Lawler is working on the votes, he has fellow skeptics of fill practices in Councilmen Benny Johnson and Randy Clouatre.

Clouatre said he would open to limiting fill for subdivisions only as long as flooded people could get back in their homes. He said understands the engineering and the calculations but doubts big subdivisions built in large floodplains won't alter drainage and doesn't see how a detention pond canmake up all the difference.

"I see real life," Clouatre said.

Read the original here:

Ascension eyes moratorium on certain kinds of housing development - The Advocate