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 bed form in the base at the inlet end of the channel, and at least one additional bed form in the channel downstream of the weir. Each bed form has an upper portion and a downwardly inclined downstream face extending from the upper portion to the trailing end. A spoiler is provided at or near to the trailing end of each bed form. A primary flow path for water extends over the bed forms. The trailing end of each bed form may be an extended, flat tail.