Gary E. Johnson

Surface Flow Outlets to Protect Juvenile Salmonids Passing through Hydropower Dams

We reviewed results of research conducted by engineers and biologists over the past 50 years related to development of surface flow outlets (SFOs) for juvenile salmonids that migrate downstream past hydropower dams. An SFO is a nonturbine, water-efficient passage route with an overflow structure through which flow and fish pass over a dam. Our review covered 69 SFOs in Europe and North America. We identified five main types of SFOs—low-flow bypass/sluices, high-flow sluices, forebay collectors, powerhouse retrofits, and surface spills. Most low-flow bypass/sluices are sited in Europe and on the east coast of North America, where mean annual project discharge and power production were 95 m 3 /s and 15 MW, respectively. The other four SFO types are found on the west coast of North America with 2184 m 3 /s mean annual discharge and 788 MW mean power output. A conceptual framework based on fish behavior and hydraulics for different regions of a hydropower project was developed to evaluate SFO performance. Based on available data, fish collection efficiency averaged 53%, with an average effectiveness ratio of 17:1 (percentage of fish collected and passed to percentage of inflow used for SFO attraction). Surface flow outlet technology can meet the goal of concurrent anadromous fish protection and hydropower generation.

Effect of Migration Pathway on Travel Time and Survival of Acoustic-Tagged Juvenile Salmonids in the Columbia River Estuary

Abstract We applied acoustic telemetry methods to characterize migration pathways and estimate associated travel times and survival probabilities for juvenile Chinook salmon Oncorhynchus tshawytscha and steelhead O. mykiss migrating downstream through the Columbia River estuary (from river kilometer [rkm] 86 to rkm 8). Acoustic-tagged fish were detected as migrating in the navigation channel and in off-channel areas at each of the estuarine reaches we examined during May–August 2010. However, the majority of fish traveled in the main navigation channel from rkm 86 to rkm 37, at which point most fish left the river-influenced navigation channel; crossed a broad, shallow tidal flat; and migrated the final 37 km in a secondary channel, which was characterized as having greater tidal transport than the navigation channel. The pathway used by acoustic-tagged smolts to migrate through the estuary affected their rate of travel. In most reaches, navigation channel migrants traveled significantly faster than fish ...

Injury and Mortality of Juvenile Salmon Entrained in a Submerged Jet Entering Still Water

Abstract Development of more eco-friendly hydroelectric facilities requires better understanding of the biological response of juvenile fish when they migrate through the turbines and other downstream passage facilities. Juvenile fall Chinook salmon Oncorhynchus tshawytscha were exposed to turbulent shear flows in a laboratory by using a fast-fish-to-slow-water mechanism in which test fish were carried by the fast-moving water of a submerged turbulent jet into the slow-moving water of a flume. Fish were released at six nozzle velocities: 6.1 (reference control), 12.2, 15.2, 18.3, 21.3, and 22.9 m/s. The onset of minor and major injuries occurred at 15.2 and 21.3 m/s, respectively. The acceleration magnitude threshold (m/s2) of major injury for the fast-fish-to-slow-water mechanism in this study was found to be significantly higher than that for a slow-fish-to-fast-water mechanism used in a previous study in which test fish were introduced into a turbulent jet from slow-moving water through an introduction...

Sluiceway Operations for Adult Steelhead Downstream Passage at The Dalles Dam, Columbia River, USA

Abstract Sluiceways at hydroelectric dams are designed to enable floating ice and debris to pass through the dams and may be used as an effective, nonturbine, surface route for out-migrating fishes to pass through dams. Each year, the sluiceway at The Dalles Dam on the Columbia River, USA, is normally operated between 1 April and 30 November and the spillway between 10 April and 31 August to enable downstream-migrating juvenile Pacific salmonids to pass. The only route available for fishes to pass the dam between 1 December and 31 March is through the turbines. This study evaluated downstream passage of adult steelhead Oncorhynchus mykiss at The Dalles Dam during various periods between 1 November and 10 April for years 2008 through 2010. The purpose of the study was to determine the efficacy of operating the sluiceway between 1 December and 31 March to provide a relatively safe, nonturbine, surface outlet for downstream passage of adult steelhead that overwinter in the lower Columbia River (i.e., fallbac...

Application of the diminishing returns concept in the hydroecologic restoration of riverscapes

Increasing our knowledge of unplanned anthropogenic synergies, which have affected ecosystems since prehistory, may facilitate ecological restoration. Predictive relationships between spatial pattern and ecosystem processes and functions in riverscapes have the potential to inform applied ecosystem restoration planning and design, where principles are needed for large-scale river reconnections. Although synergistic, additive, and antagonistic interactions affect ecosystems, the role of such interactions in restoration rarely has been evaluated. Using hydrodynamic modeling, we experimentally examine the aggregate effects of reestablishing hydrologic connections in a tidal freshwater tributary on the floodplain of the Columbia River, USA, which is currently undergoing dike breaching to restore juvenile salmon habitat. Sets of dike breaches yielded average wetted floodplain areas conforming to a two-parameter hyperbola (r2xa0=xa00.93). These findings demonstrate that the yield of inundated floodplain habitat area from dike breaching can conform to the well-established “law of the diminishing increment,” developed in the study of agriculture and economics. Furthermore, the influence of spatial configuration on yield was strong, with midstream breaches yielding 63% and upstream breaches 2% of the wetted area produced by downstream breaches, although conditions of extreme high river flow were not studied. Opening the dike at 26% of the historically present channel outlets provided the maximum return on investment for the study riverscape. Verification of this relationship elsewhere in tidal areas of the Columbia River and on other large river floodplains would contribute to cost-benefit analyses in ecological restoration program planning and have implications for effects on biota.

Species-Specific Spatial and Temporal Distribution Patterns of Emigrating Juvenile Salmonids in the Pacific Northwest

The vertical and horizontal distribution of juvenile salmonid migrants on approach to the dams influences bypass success in rivers. Accordingly, fish distributions have been studied for nearly three decades. These studies, however, have not been integrated and summarized in a single body of work to determine overall patterns in the spatial distribution of emigrants. We reviewed peer-reviewed and gray literature to summarize species-specific trends in the horizontal and vertical distributions of emigrating salmonids as measured by several different methods. We found that there were no species-specific differences in horizontal distributions and that fish were often oriented with the river thalweg. There were weak differences between species in vertical distributions, e.g., juvenile yearling steelhead were shallower during the day than yearling Chinook salmon. For sockeye, coho, and subyearling Chinook salmon, the data were limited or conflicting. Studies were purposefully designed to measure distributions at certain dams under particular environmental conditions for specific, local purposes. The non-standard sampling design has hampered the development of testable hypothesis on fish distributions in the Snake and Columbia rivers. Recent advances in individual-based models are offering the potential to forecast fish distributions near dams and facilitate improved bypass system design.

An expert panel process to evaluate habitat restoration actions in the Columbia River estuary.

We describe a process for evaluating proposed ecosystem restoration projects intended to improve survival of juvenile salmon in the Columbia River estuary (CRE). Changes in the Columbia River basin (northwestern USA), including hydropower development, have contributed to the listing of 13 salmon stocks as endangered or threatened under the U.S. Endangered Species Act. Habitat restoration in the CRE, from Bonneville Dam to the ocean, is part of a basin-wide, legally mandated effort to mitigate federal hydropower impacts on salmon survival. An Expert Regional Technical Group (ERTG) was established in 2009 to improve and implement a process for assessing and assigning survival benefit units (SBUs) to restoration actions. The SBU concept assumes site-specific restoration projects will increase juvenile salmon survival during migration through the 234xa0km CRE. Assigned SBUs are used to inform selection of restoration projects and gauge mitigation progress. The ERTG standardized the SBU assessment process to improve its scientific integrity, repeatability, and transparency. In lieu of experimental data to quantify the survival benefits of individual restoration actions, the ERTG adopted a conceptual model composed of three assessment criteria-certainty of success, fish opportunity improvements, and habitat capacity improvements-to evaluate restoration projects. Based on these criteria, an algorithm assigned SBUs by integrating potential fish density as an indicator of salmon performance. Between 2009 and 2014, the ERTG assessed SBUs for 55 proposed projects involving a total of 181 restoration actions located across 8 of 9 reaches of the CRE, largely relying on information provided in a project template based on the conceptual model, presentations, discussions with project sponsors, and site visits. Most projects restored tidal inundation to emergent wetlands, improved riparian function, and removed invasive vegetation. The scientific relationship of geomorphic and salmonid responses to restoration actions remains the foremost concern. Although not designed to establish a broad strategy for estuary restoration, the scoring process has adaptively influenced the types, designs, and locations of restoration proposals. The ERTG process may be a useful model for others who have unique ecosystem restoration goals and share some of our common challenges.

Shallow Tidal Freshwater Habitats of the Columbia River: Spatial and Temporal Variability of Fish Communities and Density, Size, and Genetic Stock Composition of Juvenile Chinook Salmon

AbstractWe investigated the spatial and temporal variability of the fish community and the density, size, and genetic stock composition of juvenile Chinook Salmon Oncorhynchus tshawytscha in shallow tidal freshwater habitats of the Columbia River. We sought to address data gaps related to juvenile Chinook Salmon in this portion of the Columbia River and thereby inform habitat restoration efforts. We examined fish communities, juvenile salmon life history characteristics, and relationships between salmon density and habitat conditions by using beach seine data collected over a 63-month period (2007−2012) from two tidal freshwater areas: the Sandy River delta (river kilometer [rkm] 188–202) and the lower river reach (rkm 110–141). We found few differences in the fish community across the two study areas. Fish community patterns were largely attributable to seasonal changes as opposed to spatial gradients and habitat types. Juvenile Chinook Salmon were the most common salmon species in our catches; this spec...

Establishing and using study criteria to ensure the rigor and robustness of survival compliance testing at hydroelectric dams

An elaborate set of criteria have been developed by fish managers and regulators to assure the accuracy, precision, representativeness, and robustness of survival compliance studies coordinated within the Federal Columbia River Power System in the northwestern USA. Dam passage survival, defined as survival from the dam face to the tailrace mixing zone, must be ≥96xa0% for spring out migrating juvenile salmonids [i.e., yearling Chinook salmon (Oncorhynchus tshawytscha) and steelhead (O. mykiss)] and ≥93xa0% for summer outmigrants (i.e., subyearling Chinook salmon). Survival must be estimated with a standard error ≤1.5xa0%. However, these quantitative benchmarks are only part of a multifaceted set of criteria, including representative dam operations, river discharge levels, and fish selection, along with tests of model validity that must be satisfied. These criteria are illustrated using acoustic-tag survival compliance studies conducted at The Dalles Dam on the Columbia River, 2010–2012. The results suggest evaluation criteria for survival compliance tests must balance the needs for rigor and robustness with the ability to reasonably perform the tests in naturally varying riverine systems.

Sluiceway Operations to Pass Juvenile Salmonids at The Dalles Dam, Columbia River, USA

Abstract Existing ice and trash sluiceways are commonly used as benign, nonturbine routes for downstream passage of juvenile salmonids at hydropower dams. At The Dalles Dam on the Columbia River, we studied various operational configurations of sluiceway weirs to maximize sluiceway passage of juvenile Pacific salmon Oncorhynchus spp. and steelhead O. mykiss. We applied hydroacoustic methods to compare fish passage rates and sluiceway efficiencies for two weir configurations in each year: three weirs (SL 1; i.e., collectively referring to the three weirs above main turbine unit [MU] 1) versus six weirs (SL 1+18) during 2004; and middle (SL 2+5) versus east (SL 2+19) powerhouse weir locations during 2005. Horizontal distributions at the sluiceway and turbines and the effects of operating turbines beneath open sluiceway gates were also analyzed. Sluiceway passage efficiency relative to the powerhouse (SLY phs ) varied between study years, between spring and summer, and between day and night. In 2004, sluicew...