this is where the water level reached in 73. reporter: 73. yep. that was part of the wall that held it back. reporter: now a 22-foot wall protects historic downtown morgan city. it will be water all the way. it will touch this wall and extend to that wall over there. reporter: you re confident about these walls holding up? i have to be. yes. have to be. reporter: and if for whatever reason they fail? total catastrophe. this entire city would flood. reporter: national guard soldiers are building up levees around town, and it seems like everyone in these neighborhoods has a boat many the driveway ready to go. gerald will stay on the back porch. you ll silt back here and watch the water creep up? pull my chairs over here and sit here and watch, maybe catch some fish. reporter: ed lavandera, cnn, morgan city, louisiana. our reynolds wolf is with us now. roenz, tell us more about the