Testing: Proven Fish Protection
There have been numerous hydraulic and biological tests performed on the Farmers Screen both in the laboratory and in the field.
Early hydraulic testing on the horizontal flat plate screen technology concept was performed by the Bureau of Reclamation in the Water Resources Research Laboratory in Denver, CO from 2000 to 2001 with a final report being published in February of 2005. The report can be found under the name “Hydraulic Performance of a Horizontal Flat-Plate Screen” Hydraulic Laboratory Report HL-2004-05, authored by Kathleen H. Frizell and Brent W. Mefford. A biological test was performed in the same laboratory using the same physical screen model by the Larval Fish Laboratory out of Colorado State University. The biological test report can be found under the title “Bull Trout Performance During Passage Over a Horizontal Flat Plate Screen” with a final report date of July 20, 2002 and authored by Dr. Daniel W. Byers and Dr. Kevin R. Bestgen and identified as “Larval Fish Laboratory Contribution Number 128”. This early laboratory testing of prototype designs provides a foundation for understanding the hydraulic performance of horizontal flat plate screens in relation to specific design components. The testing also points to some areas for improvement in the design to provide more favorable hydraulic characteristics for both fish protection and debris and sediment management.
More recent testing on installed Farmers Screens include biological testing performed by the United States Geological Survey (USGS), Western Fisheries Research Center, Columbia River Research Laboratory at a Farmers Screen installation at the Oxbow Fish Hatchery in Cascade Locks, OR. 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 and authored by Matthew G. Mesa, Brien P. Rose, and Elizabeth S. Copeland. This biological testing examines the effects on juvenile coho salmon and steelhead trout as they pass through a Farmers Screen system under various hydraulic and operating conditions, specifically analyzing injury and mortality rates as well as potential to cause delay in out migration for salmonids. The results of the testing show a very high level of protection that exceeds NMFS standards as well as a very low likely hood of delay with 99.6 % of test fish passing over the screen without hesitation or delay.