The Mississippi River appeared to hit its crest Tuesday in Baton Rouge after an extended rise following heavy rain up river, reaching the seventh-highest level in recorded history, authorities said.
The high water on the Mississippi has had the U.S. Army Corps of Engineers and area levee districts in a continuous flood-fight mode since late October, reaching 144 days on Tuesday with at least another month on the horizon.
"It's been a very, very long high-water season, and it just keeps looking like it's gonna keep going for us," said Ricky Boyett, a Corps spokesman in New Orleans. "We don't have an end."
The Corps opened the Bonnet Carre' Spillway upstream of New Orleans on Feb. 27 to relieve pressure on that city's levees. In the spillway's nearly 90-year history, it was the first time the Corps had opened the spillway in back-to-back years. It has also been opened in three of the last four years.
Boyett said Corps officials can't say yet when the river diversion into Lake Pontchartrain will be closed again.
After briefly reaching 44 feet at the Baton Rouge gauge every day between Friday and Monday, Mississippi water levels remained at or above 44 feet most of the day Tuesday, topping out at 44.18 feet about 2 a.m., National Weather Service readings say.
The river reached 45.01 feet in May 2011 and reached its record in during the Great Flood of 1927 at 47.28 feet on May 15 of that year, according to gauge records going back at least to 1874.
Patricia Brown, a senior service hydrologist for the National Weather Service in Slidell, said gauges north and south of Baton Rouge, at Red River Landing and at Donaldsonville, were or had already crested and will start dropping, though that process is expected to take weeks.
"It's a very slow fall," she said.
Boyett said lower Mississippi River levees are holding up well. A little more than half as many "inspection points" are being monitored along the levees this year as in the May 2011 flood, though the current number still totaled more than 250. Only four of those are sand boils.
Boyett and Brown added that severe flooding on the Missouri and other rivers in the Midwest isn't expected to boost Mississippi River levels beyond what they have already reached in the Baton Rouge area, though the water headed south is expected to create another crest.
The Mississippi River in Baton Rouge reached 44.1 feet on Friday and again Monday, marking the seventh highest crest on record and the second …
That water isn't expected to reach Baton Rouge and New Orleans until mid-April, Boyett said, when levels in the Mississippi are expected to have dropped some.
"We should have enough capacity in the river to hold that (extra water) without exceeding what we have already gone through," Boyett said.
Water levels are also expected to drop on the Red River in central and northern Louisiana in the coming weeks, helping matters on the lower Mississippi, Boyett said.
One factor to watch for, however, is rainfall in the Ohio River Valley, which contributes about 60 percent of the lower Mississippi's flow.
Despite the high water, Boyett said the Mississippi is expected to fall short of levels that would require opening the Morganza Flood Control Structure in Pointe Coupee Parish.
Red River Landing, the benchmark gauge for the Morganza Spillway, is expected to reach its second highest level ever, said Brown, the Weather Service hydrologist.
The height, tentatively at 61.86 feet, has been surpassed only by high water in May 2011 when the rarely used spillway was last opened.