St. Tammany, La., Seeks Data-Driven Picture of its River Basins

The U.S. Geological Survey recently published data that outline the high water marks in the western half of the parish, which is a tool the parish can use along with elevation data from its building permits, which have been digitized.

(TNS) — Abbot Justin Brown paused outside St. Joseph Abbey's main monastery building recently to point out two marks on an exterior wall. One shows how high the Bogue Falaya River rose in a 1920s-era flood. The other mark is higher. It shows the river's level on March 11 of last year, when every building on the abbey's grounds took on water.

That's basically the same kind of information that people in western St. Tammany Parish had before heavy rains sent the Bogue Falaya and Tchefuncte rivers raging over their banks last spring.

In trying to forecast how bad flooding might be, parish officials for the most part had to rely on anecdotal accounts from long-time residents who remembered where the water had risen in the past.

A year later, St. Tammany is on its way to having a more data-driven picture of its river systems, Chief Administrative Officer Gina Campo said. Eventually, that data will help in forecasting future flood dangers and in determining what kind of projects to build to reduce flooding in a parish crisscrossed with bayous and rivers.

Rising water inundated slightly more than 1,000 homes in St. Tammany last March, 90 percent of them on the western side of the parish. FEMA paid out $5.5 million in assistance, and the toll for the parish government, in terms of damage to roads and bridges and the cost of responding, was estimated at $5.1 million.

But the flood also provided a trove of new information. The U.S. Geological Survey recently published data that outline the high water marks in the western half of the parish, for example. That's a tool the parish can use along with elevation data from its building permits, which have been digitized, Campo said.

The parish also has modeling studies in the works, some in partnership with other agencies and some being done by private contractors, she said.

The parish provided $400,000 for a total water volume model of the Pearl River basin by naval hydrologists at the Stennis Space Center, just across the Pearl in Mississippi, that is being tested now, Campo said. That model will predict the boundaries of a flood event in the eastern part of the parish, she said.

Sometime this year, the parish will have an inundation model for the Tchefuncte River basin, Campo said; the study cost almost $200,000 and is part of the parish's stormwater management plan.

A preliminary study of the Bogue Falaya basin is just getting kicked off. The parish also decided to enlarge a study of the Little Tchefuncte River basin to include the area north of La. 1077.

A year ago, officials were working with far less information, although they knew that recent heavy rains upstream would produce flooding, including in areas that had not experienced it before. Even with that warning, the rising water caught many by surprise.

Folsom resident Jan Benitez, who made the first of many 911 calls that went out that March 11, had no reason to expect a flood. Her home, a former camp on the Little Tchefuncte near the Washington Parish line, had been in her boyfriend's family for generations, and water had reached it only once, about 30 years ago.

Benitez and her 4-year-old grandson had gone to bed expecting to be safe. But her phone alarm wouldn't let her sleep, and when she realized water was coming inside, she distracted her grandson with a game of "what will sink and what will float" until a rescue boat arrived.

The house took on 6 feet of water, only to flood again in August, wiping out her boyfriend's extensive restoration work. While it's livable again, Benitez said the couple is now planning to build on a higher point of the property.

The monks and seminarians at St. Joseph Abbey were similarly surprised by the fury of the Bogue Falaya. The abbey didn't have flood insurance. "We have it now," Brown said.

The first phase of the abbey's rebuilding, funded mainly by donations, will be finished by next month. The restored buildings have been designed to be more resilient in future floods, such as by moving electrical systems out of basements.

"We can't move the river or the building," Brown noted.

While people in western St. Tammany were surprised by their rivers' destructiveness, residents along the West Pearl River on the other side of the parish are all too familiar with floods. They also had been warned days in advance that their river was going to crest, potentially at record levels, as water moved down it.

Even so, Jessica and Mitch Stubbs said they were told the water wouldn't get inside their Magnolia Forest home, and they didn't evacuate. As a result, they found themselves scrambling to move furniture to the second story after Mitch Stubbs stepped out of bed into ankle-deep water.

The Stubbses consider the flood to have been a major inconvenience rather than a disaster, even though it took months to get everything repaired.

"When we moved here, we knew it had a history of flooding. We were informed consumers," Jessica Stubbs said. She also considered her family to be flooding veterans after taking on water in Katrina. But at some point, she said, they will move, and it will be to somewhere high and dry.

Residents aren't the only ones applying their experiences from last year to their recovery and planning. Parish officials are looking toward the future, too. Campo said the parish wants to have inundation maps prepared for all of its river basins and is hopeful that more grant money will be available.

A better understanding will help the parish not only prepare before a flood but also afterward, when officials are scrambling to quantify the damage. More important, Campo said, the parish needs such information to plan major projects like regional detention ponds and to guide development.

"Now we're playing catch-up after the fact," she said. In the future, the hope is to have flood projections in place first.

©2017 The Advocate, Baton Rouge, La., Distributed by Tribune Content Agency, LLC.