A wave forming apparatus has a channel for containing a flow of water, the channel having an inlet end connected to a water supply for supplying a flowing stream of water, a base, and spaced side walls, and at least one oblique foil member adjustably mounted in the base of the channel. The oblique foil member has a leading face extending at an oblique angle to the water stream in the channel, and a trailing, venturi face with a leading portion facing one of the side walls to form a venturi or constricted pass between the side wall and leading portion of the venturi face. The leading face, venturi face, and venturi pass together are adapted to form a standing barreling wave at the venturi pass. The orientation of the oblique foil member relative to the base of the channel is adjustable in order to vary the barreling wave formation, and may be adjusted during wave formation in order move the barreling wave across the leading face.