Comment: 18:25 - 19:44 (01:19)
Source: Annenberg/CPB Resources - Earth Revealed - 20. Running Water II: Landscape Evolution
Keywords: "Nancy Powell", "Old River", dam, "Old River Control Project", river, "Mississippi River", "Atchafalaya River", tributary, "New Orleans", thalweg, scouring
Our transcription: Well, in 1973 we had a flood, which happened to be the second greatest flood that man has observed since he kept records on the Mississippi.
The greatest being the 1927 flood, which is what resulted in the Mississippi River and tributaries system and all the Structures that go with it that you see today.
We actually had to open up several Structures between Old River and New Orleans to alleviate flood waters between here and New Orleans so that New Orleans wouldn't go underwater.
What happened is that the River decided that it basically wanted to continue going down the Atchafalaya.
The thalweg of the Mississippi just moved almost right into the entrance to the Low Sill Structure and basically took out a wing wall, the forces were that powerful.
It also undermined the foundation of the Low Sill Structure.
The water actually, in addition to try to go around it, actually did go underneath the Structure.
It was only because the Structure's pile founded, and that the piles were very, very deep that the Structure remained standing.
We basically just had to open the gates and let the River go, because they were just so afraid to lose the Structure.
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