Testing for Fish Protection

There have been numerous and extensive hydraulic and biological tests performed on the Farmers Screen™ both in the laboratory and in the field.

Conceptual Testing – Early Days
These years of research led to a prototype that could undergo hydraulic testing. The first official study conducted by an outside source was performed by the U. S. Bureau of Reclamation, in the Water Resources Research Laboratory in Denver, CO from 2000-2001. A biological test was also performed in the same laboratory using the same prototype model by the Larval Fish Laboratory of Colorado State University.

This early laboratory testing of prototype designs provided a foundation for understanding the hydraulic performance of horizontal flat plate screens in relation to specific design components. The testing also pointed to some areas for improvement in the design to provide more favorable hydraulic characteristics for both fish protection and debris and sediment management. This testing yielded critical and significant changes to the design of the Farmers Screen.

A final report of the first study was published in February 2005, named: “Hydraulic Performance of a Horizontal Flat-Plate Screen” (Hydraulic Laboratory Report HL-2004-05), authored by Kathleen H. Frizell and Brent W. Mefford.

A final report of the second study can be found under the title: “Bull Trout Performance During Passage Over a Horizontal Flat Plate Screen” (Larval Fish Laboratory Contribution Number 128), dated July 20, 2002 and authored by Dr. Daniel W. Byers and Dr. Kevin R. Bestgen.

Recent Biological Testing
A biological test examined the effects on juvenile coho salmon and steelhead trout as they pass through a Farmers Screen system under various hydraulic and operating conditions. Specifically, it analyzed injury and mortality rates as well as potential to cause delay in out-migration of salmonids. The results of the testing showed a very high level of protection—exceeding NMFS standards—including 100% protection and 99.6% of test fish passing over the screen without hesitation or delay.

The testing was conducted on a recently-installed Farmers Screen at the Oxbow Fish Hatchery in Cascade Locks, Oregon. This testing was performed by the United States Geological Survey (USGS), Western Fisheries Research Center, Columbia River Research Laboratory. The final report was published in late 2010 under the name: “Biological Evaluations of an Off-Stream Channel, Horizontal Flat-Plate Fish Screen—The Farmers Screen” (Open-File Report 2010-1042), authored by Matthew G. Mesa, Brien P. Rose, and Elizabeth S. Copeland.