One of my favorite rivers is the Tryweryn, in Bala North Wales. I’ve visited numerous times and have always enjoyed both the upper and lower sections. The upper section runs past the National White Water Centre for Wales, which is an incredibly useful facilities for paddlers, for both showers and for the cafe! The river is dam released so you are always guaranteed good water levels (so long as you check the release schedule), which means for the upper section they have also rearranged some of the boulders/river bed to create some awesome features.
The Upper Section (Continuous Grade 3)
You start this section just below the chipper, which is a river wide meshed fence which quite frequently pins upstream paddlers against it!
The upper Tryweryn has some very famous rapids including the Graveyard, Ski Jump, Fingers, NRA Bridge, Cafe Wave and Chapel Falls. All have their own tricky section, the International Wave at the end of the Ski Jump being famous for catching people out, the class surf wave at Cafe Wave of the sticky stopper at Chapel Falls. Part of the reason the upper Tryweyn is so good is because the centre has been able to reconstruct the river bed the features are fantastic and there are eddies of all sizes. This means that for practicing moves like breaking in and out, S Turns, Surfing Waves and Ferry-gliding there are numerous possibilities. You could easily spend hours on the first rapid (the Graveyard) tuning up your skills on the different eddies and features.
The Lower Tryweryn(Grade 2+, with one Grade 4)
The lower is a fantastic beginners section of White Water, at Grade 2, it offers a lot of great learning features for easy, and simple white water, for this reason it is particularly popular with large groups and clubs.
Unlike the upper, the lower section has been left as a natural river although is still Dam released. It starts underneath chapel falls, and keeps up interest the whole way down, with several great teaching spots such as the campsite wave. The section ends with a bang at Bala Mills Fall, a grade 3 lead in rapid to a grade 4 fall. It is easily spotted (there are several signs and the river narrows) and easily portage able on a large path, or via the leet system they have built to help portaging, which you can float down. Ball Mills Fall itself is fairly easy if you can line yourself up correctly, and comprises of a long Grade 3 lead in rapid with a 2 step Grade 4 fall, afterward a quick rapid down the slalom run and the water is easy again until the end of the section and the get out.