Poutès Dam, River Allier, France
Quoich Dam, River Garry, Scotland
July 30, 2020
Włocławek Dam, River Vistula, Poland
December 20, 2017
Case Study Number: 3
Dam name: Poutes
River name: Allier
River extension: 420,7 km
RIVER surface area: 14,350 Km2
Built date: 1941
Hydropower concession: 1956
Status: Active, concession to 2075
AMBER TOOLS: Drone Survey (D2.4), Molecular toolkit (D2.5)


The ability to produce electricity has altered the ecological situation extensively in the Allier river system, especially with the advances in engineering which have slowly allowed the construction of larger dams. This very rapid development of hydropower plants on all large and small rivers has had major consequences including, the disappearance and decline of many populations of migratory fish.

Poutès dam is located in the upper River Allier (France), the main tributary of the River Loire. This river is of great importance for Atlantic salmon, as it includes the most functional spawning zones of the Loire River basin, especially in the area of the Poutès dam. The dam was built in 1941 and constituted a total barrier to migration until 1986. Fish passage solutions for upstream (in 1986) and downstream migration (in 1987) were then implemented and progressively improved from 1986 to the early 2000s. However, a number of problems remained: migratory delay for upstream and downstream migration and difficulty in using the fishways.

Atlantic salmon (Salmo salar) is a famous anadromous species, with both juveniles (smolts) and adults undertaking long migrations between freshwater and marine habitats. Unfortunately, the species has undergone a general decline. Recruitment of the European stock has been divided almost three-fold (from 8 to 3 million) since the early 1970s and river fragmentation is frequently reported as the main cause of this decline.


  • Direct or delayed mortality when encountering hydroelectric facilities
  • Elevation of the energy cost of migration, exposing fish to predation and reduced passage success
  • Decreased migration speed and decreased smolt survival as migration timing and optimum environmental conditions are out of phase


AMBER investigated whether eDNA can recover reliable information about communities of fish, invertebrates and primary producers (cyanobacteria, algae and vascular plants) that may contribute to an assessment of stream connectivity. To this aim, twenty sites distributed along an altitudinal gradient of approximately 1000m along the mainstream of the Allier river (Loire basin, central France) were sampled at relatively constant increments in altitude of 50m, covering over 400km of stream. Thirty-two barriers had been previously recorded for this length of the river, including ramps/bed sills, culverts, weirs and dams that are distributed along the main-stream sampling range.

The project also analysed migration dynamics, transfer rates and passage hours and residence time and behaviour in the reservoir


  • Drone survey (D2.4)
  • Molecular toolkit (D2.5)


In 2011, it was decided to reconfigure the Poutès dam. Objectives were set to maintain hydropower production while meeting ecological connectivity requirements (for sediment and fish).

Temporary operating measures were implemented in the interim period, in 2017 of lowering the reservoir level from 1st March, creating a functional bypass system, softening the bypass walls to prevent abrasion injury and modulation of turbine operation for 20 nights, from 7pm to 7am, local time, when smolts were caught in the rotary screw or when river flow exceeded a threshold of 20 m3.s-1.

In 2018, it was decided to entirely stop the turbine operations instead of merely modulating them.


When the Poutès-Monistrol hydropower complex was relicensed in 2011, and after several years of concerted discussions between the French authorities, the hydropower company EDF, local representatives and environmental protection associations, it was decided to reconfigure the Poutès dam. Objectives were set to maintain hydropower production while meeting ecological connectivity requirements (for sediment and fish). These objectives were supported by an ambitious scientific program to monitor the ecological benefit of the reconfiguration.


Bach, J. M., I. Caut, M. Lelièvre & J. Viallard. 2004. Suivi de la dévalaison 2004 des saumoneaux au droit du barrage de Poutès. LOGRAMI, Saint Pourçain sur Sioule.
Baisez A, Bach JM, Leon C, Parouty T, Terrade R, Hoffmann M, Laffaille P (2011) Migration delays and mortality of adult Atlantic salmon Salmo salar en route to spawning grounds on the River Allier, France. Endang Species Res 15:265-270. https://doi.org/10.3354/esr00384
Bosc, S., Nars, A. & Menchi, O. 2017. Contrôle de la migration des smolts de saumon atlantique en dévalaison. Stations de Camon et Pointis sur la Garonne. Année 2017. Rapport MIGADO:51.
Byrne, C. J., Poole, R.G. Rogan, Dillane, M. & Whelan, K. F. 2003. Temporal and environmental influences on the variation in Atlantic salmon smolt migration in the Burrishoole system 1970–2000. Journal of fish biology 63:1552-1564.
Calenge, C. 2011. Home range estimation in R: the adehabitatHR package. Office national de la classe et de la faune sauvage: Saint Benoist, Auffargis, France.
Calles, O., Karlsson, S., Vezza, P., Comoglio, C. & Tielman, J. 2013. Success of a low-sloping rack for improving downstream passage of silver eels at a hydroelectric plant. Freshwater Biology 58:2168-2179.
CNSS. 2013. Suivi de la dévalaison dans la zone refuge à l'aide de tambours rotatifs à Alleyras et Chanteuges Année 2013. Conservatoire National du Saumon Sauvage, Chanteuges.
CNSS. 2014. Suivi de la dévalaison dans la zone refuge à l’aide de tambours rotatifs à Alleyras et Chanteuges. Année 2014. Conservatoire National du Saumon Sauvage, Chanteuges.
Courret, D., & Larinier, M. 2008. Guide pour la conception de prises d'eau Ichtyocompatibles pour les petites centrales hydroélectriques. GHAAPPE.
Coutant, C. C. & Whitney, R. R. 2000. Fish Behavior in Relation to Passage through Hydropower Turbines: A Review. Transactions of the American Fisheries Society 129:351-380.
Crozier, L. G. & Hutchings, J. A. 2014. Plastic and evolutionary responses to climate change in fish. Evolutionary Applications 7:68-87.
Cuinat, R. 1988. Atlantic Salmon in Extensive French River System: The Loire-Allier. In: Mills D., Piggins D. (eds) Atlantic Salmon. Springer, Dordrecht.
Dobson, D. 1994. Scottish emigration to Colonial America, 1607-1785. University of Georgia Press, Athens.
Friedland, K. D., MacLean, J. C., Hansen, L. P., Peyronnet, A. J., Karlsson, L., Reddin, D. G., Ó Maoiléidigh, N. & McCarthy, J. L. 2009. The recruitment of Atlantic salmon in Europe. ICES Journal of Marine Science 66:289-304.
Gauld, N. R., Campbell, R. N. B. & Lucas, M. C. 2013. Reduced flow impacts salmonid smolt emigration in a river with low-head weirs. Science of the Total Environment 458:435-443.
Grill, G., Lehner, B., Thieme, M., Geenen, B., Tickner, D., Antonelli, F., et al. 2019. Mapping the world’s free-flowing rivers. Nature, 569: 215.
Havn, T. B., Thorstad, E. B., Teichert, M. A. K., Sæther, S. A., Heermann, L., Hedger, R. D., Tambets, M., Diserud, O. H., Borcherding, J. & Økland, F.. 2018. Hydropower-related mortality and behaviour of Atlantic salmon smolts in the River Sieg, a German tributary to the Rhine. Hydrobiologia 805:273-290.
Huusko, R., P. Hyvärinen, M. Jaukkuri, A. Mäki-Petäys, P. Orell & J. Erkinaro. 2017. Survival and migration speed of radio-tagged Atlantic salmon (Salmo salar) smolts in two large rivers: one without and one with dams. Canadian journal of fisheries and aquatic sciences 75:1177-1184.
Imbert, H., Martin, P., Rancon, J., Graffin, V. & Dufour, S. 2013. Evidence of late migrant smolts of Atlantic salmon (Salmo salar) in the Loire-Allier System, France. Cybium 37:5-14.
Isaak, D. J., Young, M. K., Nagel, D. E., Horan, D. L. & Groce, M. C. 2015. The cold-water climate shield: delineating refugia for preserving salmonid fishes through the 21st century. Global Change Biology 21:2540-2553.
Jonsson, B. & Jonsson, N. 2009. A review of the likely effects of climate change on anadromous Atlantic salmon Salmo salar and brown trout Salmo trutta, with particular reference to water temperature and flow. Journal of fish biology 75:2381-2447.
Jonsson, N. & Jonsson, B. 2014. Time and size at seaward migration influence the sea survival of Salmo salar. Journal of fish biology 84:1457-1473.
Larinier, M. & Dartiguelongue, J. 1989. La circulation des poissons migrateurs: le transit a travers les turbines des installations hydroélectriques. Bulletin français de la pêche et de la pisciculture 312-313:1-94.
Larinier, M. & Travade, F. 2002. Downstream migration: problems and facilities. Bulletin français de la pêche et de la pisciculture 364 supplément:181-207.
Limburg, K. E. & Waldman, J. R. 2009. Dramatic declines in North Atlantic diadromous fishes. Bioscience 59:955-965. Lucas, M. C. & Baras, E. 2001. Migration of Freshwater Fishes. Blackwell Science, Oxford, UK.
Marschall, E. A., Mather, M. E., Parrish, D. L., Allison, G. W. & McMenemy, J. R. 2011. Migration delays caused by anthropogenic barriers: modeling dams, temperature, and success of migrating salmon smolts. Ecological Applications 21:3014-3031.
McCormick, S. D., Hansen, L. P., Quinn, T. P. & Saunders, R. L. 1998. Movement, migration, and smolting of Atlantic salmon (Salmo salar). Canadian journal of fisheries and aquatic sciences 55:77-92.
Minster, A. M. & Bomassi, P. 1999. Repérage et évaluation des surfaces potentielles de développement de juvéniles de saumons atlantiques. Proposition d’un modèle de gestion des stocks sur les bassins de l’Allier et de l’Arroux. LOGRAMI/CSP DR6.
Morita, K. 2018. Earlier migration timing of salmonids: an adaptation to climate change or maladaptation to the fishery? Canadian journal of fisheries and aquatic sciences: 1-5.
Nyqvist, D., Elghagen, J., Heiss, M. & Calles, O. 2018. An angled rack with a bypass and a nature- like fishway pass Atlantic salmon smolts downstream at a hydropower dam. Marine and freshwater research 69:1894-1904.
Nyqvist, D., Greenberg, L. A., Goerig, E., Calles, O., Bergman, E., Ardren, W. R. & Castro-Santos, T. 2017a. Migratory delay leads to reduced passage success of Atlantic salmon smolts at a hydroelectric dam. Ecology of Freshwater Fish 26:707-718.
Nyqvist, D., McCormick, S., Greenberg, L., Ardren, W., Bergman, E., Calles, O. & Castro-Santos, T. 2017b. Downstream Migration and Multiple Dam Passage by Atlantic Salmon Smolts. North American Journal of Fisheries Management 37:816-828.
Otero, J., L'Abée-Lund, J. H., Castro-Santos, T., Leonardsson, K., Storvik, G. O., Jonsson, B., Dempson, B., Russell, I. C., Jensen, A. J. & Baglinière, J. L. 2014. Basin-scale phenology and effects of climate variability on global timing of initial seaward migration of Atlantic salmon (Salmo salar). Global Change Biology 20:61-75.
Pracheil, B. M., DeRolph, C. R., Schramm, M. P. & Bevelhimer, M. S. 2016. A fish-eye view of riverine hydropower systems: the current understanding of the biological response to turbine passage. Reviews in fish biology and fisheries 26:153-167.
Roy, R., Beguin, J., Argillier, C., Tissot, L., Smith, F., Smedbol, S. & De-Oliveira, E. 2014. Testing the VEMCO Positioning System: spatial distribution of the probability of location and the positioning error in a reservoir. Animal Biotelemetry 2:1-7.
Silva, A. T., Lucas, M. C., Castro-Santos, T., Katopodis, C., Baumgartner, L. J., Thiem, J. D., et al. 2018. The future of fish passage science, engineering, and practice. Fish and Fisheries, 19: 340-362.
Silverman, B. W. 1986. Density estimation for statistics and data analysis. CRC press.
Stich, D. S., Bailey, M. M., Holbrook, C. M., Kinnison, M. T. & Zydlewski, J. D. 2015. Catchment- wide survival of wild-and hatchery-reared Atlantic salmon smolts in a changing system. Canadian journal of fisheries and aquatic sciences 72:1352-1365.
Sykes, G. E., Johnson, C. J. & Shrimpton, J. M. 2009. Temperature and flow effects on migration timing of Chinook salmon smolts. Transactions of the American Fisheries Society 138:1252- 1265.
Teichert, N., Benitez, J. P., Dierckx, A., Tétard, S., Oliveira, E., De Trancart, T. Feunteun, E. & Ovidio, M. manuscript submitted for publication. Development of an accurate model to predict the phenology of Atlantic salmon smolt spring migration.
Tétard, S., Lemaire, M., De Oliveira, E. & Martin, P. 2016a. Use of 2D acoustic telemetry to study the behaviour of atlantic salmon smolts (Salmo salar) approaching Poutès Dam (Allier River, France). Paper 26123 in, Tétard S, Lemaire M, De Oliveira E, Martin P (eds.)in Proceedings of the 11th International Symposium on Ecohydraulics, The University of Melbourne, Australia.
Tétard, S., Lemaire, M., Martin, A. & De Oliveira, E. 2016b. Comportement des smolts de saumon atlantique (Salmo salar) au voisinage du barrage de Poutès (Allier, France). Bilan des études de télémétrie acoustique réalisées en 2014 et 2015. EDF R&D.
Tétard, S., Maire, A., Lemaire, M., De Oliveira, E., Martin, P. & Courret, D. 2019. Behaviour of Atlantic salmon smolts approaching a bypass under light and dark conditions: Importance of fish development. Ecological Engineering 131:39-52.
Thorstad, E. B., Havn, T. B., Sæther, S. A., Heermann, L., Teichert, M. A. K., Diserud, O. H., Tambets, M., Borcherding, J. & Økland, F. 2017. Survival and behaviour of Atlantic salmon smolts passing a run-of-river hydropower facility with a movable bulb turbine. Fisheries Management and Ecology 24:199-207.
Thorstad, E. B., Økland, F., Aarestrup, K. & Heggberget, T. G. 2008. Factors affecting the within- river spawning migration of Atlantic salmon, with emphasis on human impacts. Reviews in fish biology and fisheries 18:345-371.
Thorstad, E. B., Whoriskey, F., Uglem, I., Moore, A., Rikardsen, A. H. & Finstad, B. 2012. A critical life stage of the Atlantic salmon Salmo salar: behaviour and survival during the smolt and initial post-smolt migration. Journal of fish biology 81:500-542.
Tomanova, S., Courret, D. & Alric, A. 2017. Protecting fish from entering turbines: the efficiency of a low-sloping rack for downstream migration of Atlantic salmon smolts. La Houille Blanche: 11-13.
Tomanova, S., Courret, D., Alric, A., De Oliveira, E., Lagarrigue, T. & Tétard, S. 2018. Protecting efficiently sea-migrating salmon smolts from entering hydropower plant turbines with inclined or oriented low bar spacing racks. Ecological Engineering 122:143-152.
Whalen, K. G., Parrish, D. L. & McCormick, S. D. 1999. Migration timing of Atlantic salmon smolts relative to environmental and physiological factors. Transactions of the American Fisheries Society 128:289-301.
Williams, J. G., Armstrong, G., Katopodis, C., Larinier, M. & Travade, F. 2012. Thinking like a fish: a key ingredient for development of effective fish passage facilities at river obstructions. River Research and Applications 28:407-417.
Winter, J. 1996. Advances in underwater biotelemetry. Fisheries techniques, 2nd edition. American Fisheries Society, Bethesda, Maryland: 555-590.