Behavior and passage of juvenile salmonids during the evaluation of a behavioral guidance structure at Cowlitz Falls Dam, Washington, 2011

Abstract

A radiotelemetry evaluation was conducted during April-October 2011 to describe movement patterns, forebay behavior, and passage of juvenile steelhead, coho salmon, and Chinook salmon at Cowlitz Falls Dam, Washington. The primary focus of the study was to describe fish behavior near a behavioral guidance structure (BGS) and floating surface collector (FSC) deployed upstream of Cowlitz Falls Dam. A secondary focus was to determine the proportion of tagged fish that were detected near spillbays 2 and 3 on the dam, because this location has been proposed for deploying weir boxes as an additional dam-based collection alternative in the future. Juvenile steelhead (Oncorhynchus mykiss), coho salmon (Oncorhynchus kisutch), and Chinook salmon (Oncorhynchus tshawytscha) were collected and tagged at the Cowlitz Falls Fish Collection Facility and transported upstream where they were released into the Cowlitz and Cispus Rivers. We radio-tagged and released 110 juvenile steelhead, 110 juvenile coho salmon, and 110 juvenile Chinook salmon and monitored their movements in and around the BGS/FSC complex, at the dam, and downstream of the dam. We used detection records and a Markov chain model to calculate probabilities of movement between specific areas in the forebay of Cowlitz Falls Dam. These areas are referred to as states and the Markov chain model was used to create a series of tables, called transition matrices, that contained estimated probabilities of movement between states. These probabilities were insightful for understanding how radio-tagged fish moved near the BGS, FSC, and spillbays. Most tagged fish (89-91 percent) moved downstream of release sites (9 or 22 rkm upstream of the dam) and were detected in the dam forebay during the study period. Tagged fish that encountered the BGS on their first approach to the dam were distributed across the forebay, which supports the concept of using a BGS to concentrate fish near a collector entrance in the dam forebay. We found that 14 percent of the steelhead, 18 percent of the coho salmon, and 17 percent of the Chinook salmon encountered the FSC discovery area without BGS guidance on their first trip through the forebay. The BGS guided 36 percent of the steelhead, 22 percent of the coho salmon, and 46 percent of the Chinook salmon to the FSC discovery area when fish first entered the forebay, which resulted in 40-63 percent (by species) of the tagged fish arriving at the FSC discovery area. Movement patterns along the BGS showed that fish were likely to guide along the device, but also demonstrated the tendency of fish to move under the BGS and downstream to Cowlitz Falls Dam. Tagged fish that arrived at Cowlitz Falls Dam were distributed across the dam face but a high percentage of each species (65 percent of steelhead; 61 percent of coho salmon; 71 percent of Chinook salmon) arrived on the northern side of the dam. Movement probabilities near spillbays 1 and 4 showed a strong preference for tagged fish to move from the outer edges of the dam towards the center of the dam w...

A computational fluid dynamics modeling study of guide walls for downstream fish passage

“…Field studies of guide wall installations that include detailed telemetry analysis are uncommon. One such study (referenced in the Introduction Section) was performed at the Cowlitz Falls Dam in 2011 (Kock et al, 2012) using radiotelemetry to track juvenile salmonids.…”

“…Dominant vertical velocities may encourage vertical fish movement and exacerbate entrainment potential. NextEra Energy Maine Operating Services, LLC (2010), Kock et al (2012), and Faber et al (2011) showed instances where a large proportion of downstream migrating fish passed below a guide wall, possibly due to a strong vertical velocity component.…”

Experiments on the hydraulics and swimming responses of juvenile Chinook Salmon encountering a floating guidance structure

“…Mulligan, Towler, Haro, and Ahlfeld (2018) hypothesized that a guide wall at 15° would produce hydraulic conditions potentially favourable for efficient guidance. However, the ability of an engineered structure to guide fish to safe passage has been primarily tested either (a) after large‐scale implementation in existing reservoirs or (b) in laboratory studies or computer simulations without live subjects (Kock, Liedtke, Ekstrom, Tomka, & Rondorf, 2012; Mulligan, Towler, Haro, & Ahlfeld, 2017; Scott, 2014). Research directly linking fish and fluid behaviour around guidance structures may reveal relationships can be used to inform the design of guidance structures.…”