Never jump into a plunge pool without first checking it for depth and obstacles. Even gorges you know well can become clogged with fallen debris such as tree trunks. Its possible for such an obstacle to be invisible from above even if less than a foot underwater. These precautions should give you some idea of whats involved during a gorge walk. It's also useful to take a first aid kit with you.
Some gorges are of course easier to negotiate and slightly safer than others.
Some however such as Devils Bridge Falls require advanced abseiling techniques and guts to negotiate. Make sure you know what your letting yourself in for. Me scrambling around in a gorge. Select for full size image. River Mynach More gorge-walking photos.