The Farmers Screen™ takes advantage of hydraulics to manage debris and protect fish. It requires a few, commonly-found conditions to operate properly. In most cases, these requirements do not create obstacles to installation:
Also referred to as “head” or “fall,” the Farmers Screen™ requires some drop in elevation from the point of diversion to the end of the screen structure: typically, a total of 1 foot is more than adequate. This differential must exist in both the conveyance and the source river or stream.
The site must be off-channel with flow to the screen regulated by a headgate. There must be adequate space to accommodate the screen structure in a place that is protected from high flow events.
There must be adequate flow in the river or stream to ensure that the proper amount of by-pass flow (flow returning to the river or stream along with fish and debris) is available 100% of the time the screen is operating. The necessary by-pass flow quantity is a function of screen design and is determined during the design process.
Stream or River Gradient
The slope of the river or stream must exceed the slope of the diverted water conveyance in order to prevent any backwater influence in the pipe.