Yes, if you own land on a flood plain you should expect (even welcome?) short period flooding BUT... you shouldn't expect to have the land flooded for extended periods.

As to dredging being needed every few years, that's ridiculous because by that token the rivers would be completely choked by now.

If the bed of a river was, for instance 15 feet below the level of the land at the banks, deepening that river so that the bed is 20 feet below the level of the land at the bank would reduce the time any flooding occurred on the flood plain.