Abstract: A sliding valve assembly is provided which has particular use in irrigating large fields. An inner resilient conduit is provided with overlapping edges which is restrained from expanding under water pressure by an outer concentric flexible cover having abutting edges positioned over the overlapping edges of the inner conduit and being opened and closed by a slide fastener. A discharge tube extends through the opening in the cover and between the overlapping flaps of the conduit and has an inner arcuate member corresponding to the contour of the conduit and a similar outer arcuate clamping member which clamped together with the flanges therebetween. The water pressure and the clamping members form a tight seal at the overlapping edges where the discharge tube extends into the conduit so that fluid within the conduit can be discharged to an appropriate point of use.