[markbnj]

You can see that the reflected waves have a big impact on the shape of the incoming waves as soon as the first of them reach the far end. I'm no hydrologist but it seems to me that the shape of the trough concentrates this effect in a way that would not happen in a more natural open environment like a shore or dike. I suppose they can account for this in their experiments. Very cool machine in any case. I love large-scale experimentation like this.