Okay kiddo, have you ever played with a sandcastle at the beach? Well, imagine that the ocean is a really big bully and it keeps knocking down your sandcastle with its waves. That's kinda like what happens with big rivers sometimes - when they have really big floods, the water can be very strong and attack the land.
So some really smart people came up with an idea to help protect the land and people from the big bully river. They built walls made of dirt and concrete called "levees" - these walls are like big sandcastles that are way stronger and bigger. Levees can stop the river water from spilling onto the land and hurting people's homes and businesses.
Now, when the levees are built or fixed or just need to be checked to make sure they're still strong, there is a special ceremony called a "levee ceremony". It's like a party where important people get together and shake hands and give speeches and thank everyone who worked hard to build and keep the levees strong.
So you see kiddo, the levee ceremony is a way to show how much we care about keeping each other safe and protecting homes and businesses from the water that can be really strong like a big bully.