Comparing Fish Screen Performance to Physical Design Criteria

Abstract

Fish screens associated with irrigation diversion structures perform a vital function by protecting rearing and migrating fishes. Irrigation diversions in the western United States were developed in the late 1800s and early 1900s with little regard to how they might affect fish populations. Fish screens were installed on some diversions beginning in the 1930s but were often ineffective. Beginning in the 1980s a “modern‐era” fish screening program was initiated in the Yakima River basin in Washington State. A systematic phased approach was employed, with federal funding, to replace antiquated screens and to install screens where there had not previously been fish protection devices. Also during this time, the federal and state agencies responsible for protecting the fish resources developed regional criteria to guide design of these facilities. These criteria, developed by the National Marine Fisheries Service and used by the Washington Department of Fish and Wildlife, dictated physical metrics such as approach velocity (and mesh size) for fish screen facilities. Scientists at the Pacific Northwest National Laboratory (PNNL) developed methods for evaluating new fish screen facilities as they came “on line” to document whether the facilities were designed, constructed, operated, and maintained to be within the fish passage criteria. PNNL uses a combination of water velocity measurements, visual inspection, and underwater videography to determine whether fish screen sites are within the fish protection criteria. This annual evaluation schedule (most sites are evaluated three times/year) is a vital tool to ensure that the large initial capital investment (over $75 million USD) is being operated and maintained to protect fish.

Evaluation of a Fish Passage Site in the Walla Walla River Basin, 2009 Annual Report : September 2008 - August 2009.

“…Pacific Northwest National Laboratory researchers developed the methods currently used for evaluating screening facilities while conducting similar studies at fish screen facilities in the Yakima River basin (Blanton et al 1998(Blanton et al , 1999(Blanton et al , 2000McMichael et al 2004;Chamness et al 2007). The following is a brief discussion of the equipment and techniques used in 2008; a more detailed description of the equipment and techniques is provided in Chamness et al (2007).…”

“…These criteria provide guidelines for determining whether a site is constructed, operated, and maintained in a way that protects juvenile salmonids (McMichael et al 2004). PNNL staff compared evaluation results with these draft criteria in analyzing the water velocity measurements at the Touchet Consolidated Facility fish screens.…”

Walla Walla River Basin Fish Screen Evaluations; Nursery Bridge Fishway and Garden City/Lowden II Sites, 2005-2006 Progress Report.

“…The methods currently used for evaluating screening facilities were developed while conducting similar studies at fish-screen facilities in the Yakima River Basin (Blanton et al 1998(Blanton et al , 1999(Blanton et al , 2000Chamness et al 2001;Carter et al 2002;McMichael et al 2004). These evaluations addressed three main questions:…”

Yakima and Touchet River Basins Phase II Fish Screen Evaluation, 2006-2007 Annual Report.

“…Water has been diverted from western rivers since the mid-1850s to irrigate crops. During the 1920s, some of these diversions were equipped with fish-protection devices, but it was not until the Mitchell Act of 1938 provided funding to protect fish that screening irrigation diversions and evaluating their effectiveness truly got under way (Bryant and Parkhurst 1950;McMichael et al 2004). …”

“…Two studies conducted at the PNNL Aquatics Laboratory in Richland, Washington, used modular drum screens constructed by the Washington Department of Fish and Wildlife (WDFW) to determine fish survival through submerged orifices and the relative effectiveness of two screen configurations at bypassing fish (Abernethy et al 1996;Neitzel et al 1997). The methods currently used for evaluating screening facilities were developed while these earlier studies were conducted, then refined over the next several years (Blanton et al 1998(Blanton et al , 1999(Blanton et al , 2000McMichael et al 2004).…”