When were riverboats replaced?

The main advantage of riverboats to commercial navigation of rivers is that they are fairly shallow draft and the paddlewheel does not get tangled in vegetation, allowing them to ride over sandbars and other submerged objects that more modern propeller driven ships would get stuck on. In the US after the Army Corp of Engineers began dredging the navigation channel and building levees along major rivers used for commercial navigation the riverboat no longer had any advantages and deep draft propeller driven ships that could carry larger loads of cargo replaced the riverboat for such purposes.

However riverboats still have nostalgic value for tourists and other forms of entertainment. They are also used in other countries where the navigable rivers have not been "improved" from their natural condition as they are in the US.