A sprinkler. A sprinkler nozzle assembly is coupled to a base for rotating movement. A stationary cam with cam surface engages a cam follower which open and close valves to regulate water flow as selected angles of rotation. In an embodiment, a pop-up sprinkler is provided, and the moving components are part of the riser. A turbine drive mechanism is coupled to an upper housing on which a plurality of sprinkler nozzle assemblies are affixed. The drive mechanism includes water driven impeller and a gear train adapted for operatively driving the upper housing, and associated sprinkler nozzle assemblies.