[arjunvpaul]

The Mississippi would, but doesn't to that scale today, because the Army Core has leveed/dyked in most places.

You can see in the pictures here http://bit.ly/2u7f2ta that there is a lot of "marsh" beyond where the river bank ends. You just have to extend the roadway as far as you like. You can see how the bridge extends beyond the river on both sides.

This particular bridge for example has 18 miles of approach roadways. Only about 1600 feet of that, spans the Mississippi.

In short, if flooding adds 27 miles or 270 miles of width, the engineering is pretty much the same. You just have to know, where to start and finish :-)

[Brendinooo]

Very interesting! Thanks for this.