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How the Farmers Screen Works

Overview

1 Diversion Structure

Diversion Structure: A structure that directs flow from the river or stream into the diversion. This can be a dam, rock weir, or stem wall.

2 Head Gate

An adjustable structure that controls the flow of water entering the diversion.

3 Inlet Flume

The channel that carries water diverted from the river or stream into the screen structure.

4 Screen Structure

Fish, debris and water pass above the horizontal screening material and return to the river.

5 By-pass Return

Water, fish, and debris are returned to the original source. This can be a step pool, roughened channel, or pipe.

6 Conveyance

Screened water is conveyed to its intended users (e.g., irrigators) via pipe or canal.

Overhead View

A Inlet Flume

Attached to the upstream end of the screen, the Inlet Flume creates optimal hydraulic conditions by allowing water entering the Farmers Screen™ to achieve a uniform, steady state flow.

B Horizontal Screen

A perforated, stainless steel flat plate lies parallel to the water surface. Low downward velocity pushes water through the horizontal screen material.

Cross Section View

C Sweeping Velocity

Water sweeps over the screen surface at a velocity at least 20 times greater than the velocity of the water passing downward through the screen. This allows fish and debris to be swept over the horizontal screen material and returned to the stream while screened water can be collected and carried to irrigators via pressurized pipe.

D Taper Wall

Maintains constant velocities and uniform depth of water over the screen surface as water progresses through the structure. The taper wall decreases the cross sectional area of the flume as water is delivered through the screen.

E Weir Wall

A short, solid steel panel that runs parallel to the taper wall, the weir wall maintains a uniform depth of water over the screen and thus uniform flow through the screen.