In a preferred embodiment of the present invention a sprinkler is provided, having a first shaft coupled to a drive mechanism and a grooved deflector. A second shaft is disposed within the first shaft, coupled to a water flow adjustment mechanism and an adjustment region on the top of the deflector. The first shaft transfers rotational movement from the drive mechanism to a grooved deflector on the top of the sprinkler. The second shaft rotates with the first shaft during normal operation due to a friction clutch within the sprinkler. When the user desires to adjust the water flow (i.e., the radius of the water), the friction of the clutch can be overcome by rotating the second shaft, increasing openings of flow passages within the sprinkler body. In this respect, flow adjustments can be made from the top of the sprinkler while the deflector rotates.