Where in the world is there another river with a fast rise in tide like the river severn?
The Bay of Fundy in Nova Scotia is famous for the amount of change in water depth between low tide and high tide, and for the force and speed of the water flow when the tide comes in and goes out. There is even a so-called “Reversing Falls” on a river that feeds the Bay of Fundy. I would describe it as a “reversing rapids.” The water flows over rocks in the nature of a rapids, and depending on whether the tide is coming in or going out, the rapids run out from the river, or they go back “upstream” (when the tide is coming in).