They create either round or square patterns. Older, nonadjustable models still put out a lot of water at once, presenting a runoff risk on slopes and where water penetrates soil slowly. You can set them to a fine mist for delicate situations, like watering a newly seeded lawn. Gear-driven wheels also allow it to move along the hose as it waters, making it especially convenient for irrigating large, long lawns. Oscillating sprinklers .
Oscillators have a spray arm that flips back and forth instead of revolving.
They also use a gear mechanism, rather than straight water pressure, to determine how quickly the spray oscillates. That allows these sprinklers to lay down a gentle fan pattern slowly enough so that runoff shouldn't be a problem. While some adjustable models, including the Melnor, work fine with the water turned up or down, others get stuck in one direction when pressure is low. Oscillating sprinklers can water a square or rectangle as large as 2,000 or 3,000 sq. But because of their high-arcing spray, these sprinklers lose a lot of water to evaporation and wind.