A wave forming apparatus has a channel for containing a flow of water with an inlet end connected to a water supply, a base, and spaced side walls, a weir in the base at the inlet end of the channel, and at least one bed form in the channel downstream of the weir. The bed form has an upwardly inclined upstream face extending downstream of the leading end, an upper portion, and a downwardly inclined downstream face extending from the upper portion to the trailing end. A primary flow path for water extends over the weir and bed form. A secondary flow passageway extends through the bed form, with a first end adjacent the trailing end of the bed form, and a second end in the bed form upstream of the first end.