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Flood waters cover parts of I-10 near Siegen Lane Saturday.

Advocate Staff Photo by PATRICK DENNIS

After more than two days of rain punished the Baton Rouge area, parish officials across the region braced Saturday for more flooding as rivers swell to record levels. 

One area under close watch is the Amite River at Port Vincent as Ascension Parish officials wait and hope that the National Weather Service is wrong about just how high the river is expected to rise.

After the massive devastation in Ascension from the much-remembered 1983 storm, the parish built a levee and pump system, but designed it with the 14.6 foot level seen at Port Vincent that record-breaking year.

The NWS is forecasting the river to get above that level Sunday afternoon on the way to 16.1 feet, which could mean the water overtopping the levee and flowing to the pump station, potentially overwhelming the system. This in turn could lead to significant flooding in the southern part of the parish, including Gonzales and parts of Sorrento, explained Bill Roux, director of drainage in Ascension Parish.

Even if it doesn’t climb as high as currently forecast, but gets over the 14.6 foot mark, people could see worse flooding than in 1983 because of the increase in development that reduced the natural water-storage ability and the sinking of the ground that occurs all over south Louisiana.

“The only thing I hope for is that the National Weather Service overestimated,” Roux said.

Parish officials have been meeting and reviewing spots that could flood and will release information Sunday morning about what, if any, evacuations will be necessary, Roux said.

“Yesterday, I was guardedly optimistic. Right now, I just don’t want to think about it,” Roux said.

Two-day rainfall totals around the capital city ranged from 8 to 12 inches through Saturday afternoon, although some areas had recorded twice as much, said Danielle Manning, a meteorologist with the NWS office in Slidell.

Public reports from the Monticello and Brownfields areas showed 24.02 and 26.83 inches of rainfall, respectively, over the two-day period since Thursday, Manning said Saturday afternoon. The town of Livingston saw 21.86 inches, and the Baton Rouge Airport registered 16.21 inches, according to official NWS readings.

Those higher numbers are well over 100-year averages.

“We think they’re going to be somewhere in the 500- to 1,000-year range,” Manning said.

The rainfall has resulted in unprecedented water levels on the Comite, Amite, Tickfaw, Natalbany and Tangipahoa rivers – all of which surpassed their crests from the flood of 1983. The Comite and Amite continued to rise Saturday evening.

With more rainfall on the way -– an average of 1-3 inches through Sunday, though some areas could see more -– predicting the extent of the flooding yet to come is no easy task, Manning said.

“The problem with trying to give specific impact is that we’re above a record; it’s never happened before,” she said. “We don’t know what the impacts are going to be.”

Several officials have said they were hoping the wind would not counteract the rivers’ attempts to drain into Lakes Maurepas and Pontchartrain, as sometimes happens during hurricane events, where southeast winds drive more water into the lakes and act as a dam against the downward flow.

With the winds coming from the south now and the lakes at normal levels, that dam has not been built this time around, Manning said. But with record levels of water moving down the rivers, it’s impossible to say with any certainty how much more flooding might occur.

Two rivers in the region were predicted to crest Saturday – the Tangipahoa and the Natalbany – and the Tickfaw’s ascent slowed and appeared to crest by late afternoon, but the Comite and the Amite continued to rise.

The Comite River measured 33.52 feet at Joor Road by 5:15 p.m. Saturday, headed for a projected crest of 34.5 feet overnight Saturday.

The Amite River was projected to crest a day later, hitting an estimated 46 feet at Denham Springs by late Sunday evening and staying in major flood stage through early Tuesday morning. The river had hit 44.96 feet by 5 p.m. Saturday.

The Amite River at the Bayou Manchac Point was at 15.5 feet Saturday afternoon but was projected to get to 21.5 feet by Monday morning -– almost 2.5 feet above the record set in 1983.

Meanwhile, the Tangipahoa appeared close to topping out around 27.4 feet at Robert on Saturday evening, before beginning a slow descent toward normal. The river was projected to remain in major flood stage –- above 21 feet – until about midday Wednesday.

The Natalbany was projected to crest Saturday at 24 feet in Baptist, although at 3 p.m., the most recent reading for the river was from 8 a.m., when it hit 22.2 feet. The river was to remain in moderate flood stage only through Sunday morning.

The Tickfaw River also appeared to have crested late Saturday afternoon, measuring 22.14 feet at Holden around 12:45 p.m. and only 22.04 feet five hours later -– well shy of the 26.5-foot crest NWS continued to predict for midday Sunday.

Follow Heidi Kinchen on Twitter, @HeidiRKinchen.