The Farmers Screen uses hydraulics to effectively manage debris and protect fish. Water moves over the screen surface at a relatively high velocity (generally 2 to 8 feet per second) and moves through the screen at a relatively low velocity (maximum approach velocity of 0.25 feet per second). This combination of a high sweeping velocity and minimal downward velocity moves fish and debris over the screen and back to the river or stream. An oscillating velocity creates a pulsing action that also contributes to the self-cleaning characteristics of the screen. The combination of a weir wall and taper wall configuration keep water depths and velocities constant. The weir wall is essential for maintaining depth of water over the screen as well as consistent approach velocities. The taper wall is essential for maintaining velocities down the length of the screen by decreasing the cross sectional area of the screen flume as the volume of water in the flume decreases.