Skip to Main content Skip to Navigation
Journal articles

Protecting the downstream migration of salmon smolts from hydroelectric power plants with inclined racks and optimized bypass water discharge

Abstract : The sustained development of hydropower energy in the last century has caused important ecological impacts, promoting recent advances in efficient mitigation measures to be implemented in existing and future hydropower plants. Although upstream fish migration has been largely addressed with the development of fish-pass infrastructures, downstream passage solutions are often missing or inefficient, strengthening the need for their improvement and efficiency assessment. The efficiency of horizontally inclined (26°) low bar spacing racks associated to a bypass was assessed using salmon smolts radiotelemetry along three successive hydropower plants (HPP) in the Ariège River (southern France). In average, nearly 90% of the smolts were successfully protected by the racks and rapidly guided to the bypass, within few minutes in most cases. Furthermore, we detected a significant positive influence of the bypass discharge (Qbp% expressed as the proportion of concurrent HPP discharge) on the probability of successful bypass passage, reaching 85% of successful passage with a Qbp% of only 3%, and more than 92% when the Qbp% exceeded 5%. The probability of bypass passage without hesitation (e.g. passage within the first 5 min) also increased with Qbp%, and reached 90% with 5% of Qbp%. Passage without hesitation was especially detected on the site having larger bypass entrances and transversal currents, providing better guidance into the bypass. High-efficiency results of inclined racks yielded with reduced Qbp% confirmed their relevance to mitigate some of the HPP ecological impacts, re-establishing safe downstream salmon migration with lower impact on energy production than older less efficient solutions.
Complete list of metadata

https://hal.archives-ouvertes.fr/hal-03345248
Contributor : Open Archive Toulouse Archive Ouverte (oatao) Connect in order to contact the contributor
Submitted on : Wednesday, September 15, 2021 - 1:44:51 PM
Last modification on : Wednesday, October 20, 2021 - 3:28:03 AM

File

27412_Tomanova.pdf
Files produced by the author(s)

Identifiers

Collections

`

Citation

Sylvie Tomanova, Dominique Courret, Sylvain Richard, Pablo A. Tedesco, Vincent Mataix, et al.. Protecting the downstream migration of salmon smolts from hydroelectric power plants with inclined racks and optimized bypass water discharge. Journal of Environmental Management, Elsevier, 2021, 284, pp.112012. ⟨10.1016/j.jenvman.2021.112012⟩. ⟨hal-03345248⟩

Share

Metrics

Record views

30

Files downloads

41