A sure sign the Mississippi River is uncommonly high, the river's muddy water steadily poured Tuesday into the Bonnet Carre Spillway through a beaver-dam-like structure built after the great flood of 1927.

For now, the Army Corps of Engineers is not overly concerned about the river's high water, saying levees and spillways can easily handle the volume flowing south to the Gulf of Mexico.

"As floods go, this is not really an extreme event, as yet," said Eddie Brooks, chief of the watershed division of the corps' Mississippi Valley Division in Vicksburg, Miss.

However, that could change, he said, if it continues to rain heavily in the upper river basin. Three to four inches of rain are forecast this week for Arkansas, Missouri and Indiana and that could call for more aggressive measures, such as opening Bonnet Carre, Brooks said.

On the winding river, meanwhile, pilots and captains are navigating a risky environment, where it's harder to anchor, takes more horsepower to make turns and where currents get wilier.

"The last time we had a river of this level and magnitude was 11 years ago," said A.J. Gibbs, president of the Crescent River Port Pilots' Association, a group of pilots who navigate ocean-going ships into New Orleans.

"When the river's this high, you can't make any mistakes," he said. "We had a ship leave out of here yesterday that was 997 feet long, 131 feet wide. That's over three football fields long and you have to deal with these conditions."

The conditions prompted the Coast Guard last Friday to limit the number of barges towboats can push in the lower Mississippi. Boaters were urged to exercise extra caution.

And there have been accidents. Last week, a Greek-flagged freighter ran aground near New Orleans and caused 60 nearby barges to break loose from their moorings. On Tuesday, a stretch of the river was closed near Vicksburg when a barge sank after hitting a bridge.

"There are many contributing factors and high water is one that we'll take into consideration," said Petty Officer James Harless, a Coast Guard spokesman in New Orleans.

Meanwhile, teams are scouring hundreds of miles of levees, looking for erosion and water seepage and keeping a close eye on past trouble spots.

The ferocity of the Mississippi is entrenched in the lore of people who live along its banks.

"The Mississippi is a mighty, mighty vicious river. It's hard to keep him where he is today. If he decides to get outside those levees, there's nothing in the world we can do about it," said Reynold Minsky, president of the Fifth Louisiana Levee District, which maintains 257 miles of Mississippi levees north of Baton Rouge.

The river's ferocity was seared into the collective memory with the 1927 flood. Levees burst in the Lower Mississippi Valley and the river flooded 25,000 square miles, wiping out entire towns. More than 500 people died and about 700,000 were forced from their homes.

To save New Orleans, levees south of the city were dynamited, relieving pressure upriver but flooding St. Bernard and Plaquemines parishes. So bitter and lasting is the memory of that act that accusations surfaced of levee dynamiting during Hurricane Betsy in 1965 and Hurricane Katrina in 2005. Officials have strongly denied levees were deliberately blasted during the storms.

One of the legacies of the 1927 flood is the Bonnet Carre Spillway.

The 7,000-foot-long spillway about 40 miles north of New Orleans was one of the first major structures built after the flood. Constructed between 1929 and 1931, it is a release valve for the river before it can threaten New Orleans.

The structure was last opened in 1997, sending the river's filthy fertilizer-and-urban-runoff rich water into Lake Pontchartrain.

Environmentalists fear opening Bonnet Carre this spring would sully the lake's natural environment. Seafood harvesting also could be affected as the torrent of fresh water pours first into brackish Lake Pontchartrain and then into the salty Gulf of Mexico. Corps workers spent Tuesday testing the spillway structure for a possible opening by lifting some of the wooden beams, or "needles," to allow water to flow freely through.

"We want to be prepared," said Christopher Brantley, the spillway's project manager. "The Mississippi changes — if not daily, on a weekly basis."

Water has been pouring through the structure's fence-like series of 7,000 beams for several days, slowly pooling in the 7 miles of forest and grass that make up the spillway between the river and Lake Pontchartrain. Water is expected to continue flowing through gaps in beams for many more days.

The flow already has interrupted corps' workers extracting valuable clay from borrow pits in the spillway. The clay was being trucked to New Orleans to build up hurricane protection levees. River levees in the city are not believed to be at risk.

"By the weekend, the water should be from levee to levee, all of this grassy area will be covered," Brantley said, standing in the foreground of the structure. The spillway is bounded by levees.

The locals aren't panicking. In fact, many are looking forward to a spillway brimming with water.

"In 1997, they opened it and everybody was out here crawfishing, mud-riding, acting like a bunch of kids, playing in the mud," said Christy Rodrigue as she watched the water rise in the with her husband, Billy, a pipe-fitter.