Here the river is forced into a deep and narrow channel, a very dangerous place and you do not want to get too close here. The river thunders into this channel. If you fall in it is likely to be fatal, as it would suck you into underwater caves and eroding tunnels.
Your description is wonderful Hilda. But isn't it just this very thing that draws you closer and closer, the power, the noise. I can hear and feel both as I look at this picture. Great shot!