Ideally you want an inflatable SUP. If you’re paddling rivers you’re going to hit things. Normally semi submerged tree roots but we’ve also hit a concrete block that was just below the surface under a bridge. I used to use a hard board, but after two major repairs I switched to the JP Australia Sports Air 12’6‘.
The main problem with an inflatable is chop (small wind blown waves). The inflatable struggles to cut through these waves. However, the great news with rivers (especially small ones) is that it is almost always flatwater, even if it is windy, ie no chop.
The other advantage of the inflatable stand up paddle board is that you can stick it in the back of a taxi, so you can do an extended down stream paddle if you’d prefer. Personally I find it very satisfying to paddle up first and then return. Normally we average about 2 mph on way up and 4.5 on way down.
When the river is in full flood (like the video) the main challenge is dodging tree branches and the turbulence of the river challenging your balance.
When the river is at normal levels there maybe shallow sections where the water will run especially fast. Often paddling hard you can just about make it through these sections, however the good news is that they’re very shallow so you can just as easily pick up the board and walk up to the deeper water beyond. On the way down the river you need to watch out for the skeg catching on a rock / branch and you flying over the front of the board. To reduce the chances of this we cut down some skegs to make them shallower to use when going downstream.
The environment agency website is excellent for checking the river levels before you go. You should also check the river is not private or has restrictions. There are lots of canoe websites with this info after a quick google search.