A riser for a surface irrigation system, the riser having a housing and an outlet valve. The housing has an open upper portion and an outlet defining an orifice through which irrigation fluid is to be discharged. The valve includes an upper closure, a valve member, and an actuating lever. The upper closure is securable to the riser for sealing the open upper portion. The valve member is coupled to the closure and mountable within a flow path of the fluid, the valve member operable for opening and closing the valve, and configured to seat against a valve seat of the housing, and on an upstream side of the orifice, whereby the pressure of fluid within the valve urges the valve member against the seat when the valve is closed. The pivotable actuating lever having one end extending through the orifice and coupled to the valve member, an intermediate fulcrum, and an operable end for operating the valve member to open and close the valve.
