| Fish passage


Manager at Kleinschmidt. “The fish in this region have an ancestral and spiritual connection to the people who live here, dating back thousands of years. It is a privilege to work together towards restoration.” Kleinschmidt’s partnership with Anchor QEA brings


together expertise in engineering, biology, stakeholder facilitation, and permitting to lead this high-impact project. The combined team will coordinate with the US Bureau of Reclamation, the US Army Corps of Engineers, Bonneville Power Administration, NOAA Fisheries, the US Fish and Wildlife Service, Washington Department of Fish and Wildlife, Avista Utilities, as well as the Indigenous communities. The project is described as being a remarkable


step towards salmon restoration and honouring the cultural and ecological legacy of the Upper Columbia United Tribes. Such a transformative effort is blending science and collaboration to address generations of ecological disruption, and holds profound significance for Indigenous communities and the environment. The project’s timeline is driven by the natural lifecycle of the region’s salmon. Interim adult fish passage facilities are expected to be operational at Chief Joseph Dam by 1 July 2028, and juvenile facilities at Grand Coulee Dam by 31 March 2030.


Survival studies From 2008 to 2018, acoustic telemetry studies


evaluated dam passage survival of spring migrant Chinook salmon and steelhead smolts at seven of the eight federally operated dams on the lower Snake and Columbia rivers in the US. Data from over 87,000 dam passage events were evaluated to identify the effect of spill operations, environmental conditions, and fish characteristics on powerhouse passage probability. In general, powerhouse passage was positively


correlated with discharge, negatively correlated with forebay temperature and fish size, and higher for fish that passed the dam at night and for those that approached from the powerhouse side of the river, suggesting powerhouse passage is largely a function of smolt activity level and swimming ability. As this research by the Pacific Northwest National Laboratory and the University of Washington showed, spilling large volumes of water to reduce powerhouse passage is likely to be most effective during times of reduced activity and swimming ability (eg at night, high flows, and cold temperatures). The authors say this information can be used to develop dam- and time-specific spill operations that optimise smolt passage, power generation, and other competing demands, such as adult passage.


Strategic restoration A strategic restoration development paradigm to


break, what they call, unfavourable lock-ins from past hydropower development, has been proposed in research undertaken by Valerio Barbarossa and Rafael Schmitt, and published in One Earth. Looking at Asia’s Lower Mekong River, strategic multi-objective optimisation and habitat fragmentation modelling for 710 fish species has been used to design restoration development policies which, according to the authors, highlight the essential role of restoration in combination with strategic planning for future sustainable hydropower worldwide. “Our results show that a combination of removing


high impact dams, fishways retrofitting, and strategic planning can break locked-in environmental impacts and restore connectivity to a level achievable had strategic planning been adopted before the onset of hydropower deployment,” Barbarossa and Schmitt say. They believe their results for the Mekong make a point for integrating dam scale mitigation and strategic planning into restoration development policies. They go on to discuss that the current dam portfolio in the Mekong is “a result of non-strategic hydropower development in the past two decades”. It has also locked in avoidable trade-offs between hydropower and fish and has impacted the livelihoods of people depending on the world’s most productive freshwater fisheries. Even if strategic planning is adopted in the


future, the authors claim there remains only a limited potential to strike better trade-offs between conflicting objectives. With strategic dam removal, they believe future hydropower portfolios could achieve trade-offs similar to what could have been achieved when adopting strategic approaches from the onset of hydropower development. Although such restoration development strategies will be challenging to implement, they “would be critical to leverage hydropower’s benefits for climate mitigation with the fewest impacts on biodiversity and associated livelihoods”. In addition, exploring the benefits of restoration development also calls for significant efforts to close data and knowledge gaps.


Quantitative assessments Quantitative assessments have also been carried


out into the cost of using positive barrier screens to prevent fish entrainment at hydropower facilities. Matson et al, in their study published in The Journal of Environmental Management, say such information is of value to the hydropower community because it helps provide a comparison into the cost effectiveness of alternative strategies for protecting aquatic resources. The analyses showed that for fish exclusion


screens, capital costs per unit flow were greater for powerhouses with higher theoretical head heights (ie power governed predominately by higher-head, lower flow projects). Such higher costs could be driven by increased costs associated with materials, requirements for larger quantities of material (eg larger screens), difficulty of construction, or a combination of some or all of the above.


A case study comparison with an ongoing low-head


project by Natel Energy on the James River near Richmond in Virginia, estimated a ten-fold difference in the capital cost of exclusion if construction requires an entire stand-alone concrete structure, as opposed to replacing existing trash rack panels with 0.75-in wedge wire screen. Further exploration would benefit greatly from the inclusion of additional data.


Matson et al conclude that their data on the costs of fish exclusion screening was in general agreement with previously published qualitative information. They found that complete exclusion of fish can require high capital costs. In addition to excluding fish from turbine entrainment, the authors say capital costs may be required for the planning, construction, and evaluation of infrastructure to provide safe passage of fish across a dam, depending on stakeholder objectives and the scale of the project.


Above: Chinook Salmon


References


Flooding and dam operations facilitate rapid upstream migrations of native and invasive fish species on a regulated large river by Mark Fritts, Daniel Gibson Reinemer, Douglas Appel, Katharine Lieder, Cody Henderson, Amanda Milde, Marybeth Brey, James Lamer, Dominique Turney, Zachary Witzel, Emily Szott, Grace Loppnow, Joel Stiras, Kayla Zankle, Devon Oliver, R. John Hoxmeier & Andrea Fritts . Scientific Reports | (2024) 14:20609 https://doi. org/10.1038/s41598-024- 70076-4


Factors affecting powerhouse passage of spring migrant smolts at federally operated hydroelectric dams of the Snake and Columbia rivers Ryan A. Harnish, Kenneth D. Ham, John R. Skalski , Richard L. Townsend, and Rebecca A. Buchanan. Can. J. Fish. Aquat. Sci. 80: 1949–1966 (2023) | dx.doi. org/10.1139/cjfas-2022-0217


Strategic restoration-development mitigates trade-offs between hydropower and fish habitat fragmentation in the Mekong by Valerio Barbarossa and Rafael J.P. Schmitt. One Earth 7, 1096– 1107, June 21, 2024. Elsevier. https://doi.org/10.1016/j. oneear.2024.05.009


Estimated capital costs of fish exclusion technologies for hydropower facilities by Paul G. Matson, Kevin M. Stewart, Gbadebo A. Oladosu, Emrat Nur Marzan, Scott T. DeNeale. Journal of Environmental Management, Volume 351, 2024, 119800, ISSN 0301-479. https://doi.org/10.1016/j. jenvman.2023.119800.


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