CSLKenny
TS Member
The size of the splash is primarily created by the shape of the boat's bow. But as said, changing the water level is a simple way to vary the wetness. Obviously this can only be done in a controled pool, like Atlantica. So with a normal flume, I doubt this could be done, since the water level in the trough is hard to regulate compared to a splashdown pool. It's more suited to water coasters really.
Chiapas in Phantasialand operates during the winter (unless the temperature is below freezing). They can change the splash by lowering the water level. So it can be done on log flumes.