The scene at the Bonnet Carre Spillway Thursday tells the story, as water from the swollen Mississippi River presses against the structure, pouring through every opening.

And the river keeps rising.

“It’s something we are monitoring very closely,” Lt. Col. Murray Starkel of the Army Corps of Engineers said.

And because the river is expected to continue gaining strength, the Corps will take action on Friday for the ninth time in the structure's history when it opens the spillway.

It’s a move to ease the strain on river levees around New Orleans and points south.

“This is something we take very seriously, to protect the public and the safety of the people behind the Mississippi River and tributaries' levees, and to put the water into Lake Pontchartrain to relieve those pressures,” Starkel said.

But what is seen as a safety measure for the Crescent City, the spillway opening could have damaging effects on Lake Pontchartrain as freshwater loaded with fertilizers and other chemicals pours into the saltwater lake.

“At the least, we're going to have a lot of brown water, the clarity will decrease and the lake will become much more turbine in the near term,” Lake Pontchartrain Basin Foundation spokesman Carlton Dufrechou said. “At the worst, we could have algae blooms and dead zones.”

That's what happened in 1997, the last time the spillway was opened. Dufrechou said the '97 opening devastated the lake and its eco-systems mostly because of algae blooms, which suck oxygen out of the water, killing marine life.

But there is hope the impact won't be as dramatic this time.

There are a total of 350 individual bays that make up the Bonnet Carre Spillway. In 1997, the corps opened 298 of them. But this time around, officials expect they'll only have to open about half that amount

Still, fishing on the lake will likely take a hit.

“It’s going to get bad,” fisherman Arthur Lopez said. “No fishing out here.”

“Unfortunately for the commercial fishermen, it could wipe out the summer,” Dufrechou said.