Jakub stayed in relatively  this same spot for a half hour.  Photos 16 thru 25 will give you some idea of what he was after.  He is casting his craft at the perpetual mini rapids where each one hundreth of a second the compposition changes. 
ILCE-7R with 24-105mm F4 OSS @28 mm, 0.6 sec at f / 16, ISO 125