Performance of a large partial-depth guide wall to divert downstream migrating Atlantic salmon smolts at Tuilières dam, Dordogne River

• Published in: Knowledge and management of aquatic ecosystems 2020 (421), p.15
• Main Authors: Larinier, Michel, Dumond, Lionel, Lagarrigue, Thierry, Frey, Aurélien, Travade, François
• Format: Article
• Language: English
• Subjects: atlantic salmon smolts; Average velocity; Barrages; Bays; behaviour; Bypasses; Catadromous migrations; Depth; Downstream; downstream migration; Efficiency; Escapement; Fish; Freshwater fishes; guide wall; Guide walls; hydroelectric plant; Marine fishes; Performance evaluation; Permeability; Power plants; Probability theory; Radio telemetry; radio-tracking; Regression analysis; Regression models; Rivers; Salmo salar; Salmon; Smolts; Statistical analysis; Telemetry; Turbine engines; Turbines
• ISSN: 1961-9502; 1961-9502
• DOI: 10.1051/kmae/2020010

From 2010 to 2016, an evaluation of the performance of a partial-depth guide wall associated with three surface bypasses to ensure the safe downstream migration of Atlantic salmon smolts was conducted at the Tuilières power plant on the Dordogne River in southwestern France. The objectives of this study, during which 603 smolts were monitored using radio telemetry, were (i) to determine their escapement rate (passage through routes other than turbines), (ii) to analyse their behaviour faced with the structure and (iii) to assess the permeability of the guide wall as a function of turbine and spilling flows. The rate of escapement through the surface bypass routes varied from approximately 15% to 85%. The turbine flow was the main factor influencing the guide wall efficiency. The contribution of secondary bypasses, while significant for low flows, decreased rapidly with the increase in turbine flows. The vast majority of fish arrived on the two downstream bays of the wall or directly in the area of the main bypass, with the guiding effect of the guide wall becoming less noticeable with the increase of turbine flow. A modification of the depth of the guide wall in 2014 slightly improved its efficiency (by 5–10%) for low turbine flows. Logistic regression models were used to describe the evolution of the efficiency of the facilty as a function of the turbine flow and the probability of direct passage under a bay as a function of average velocity under this bay. De 2010 à 2016 une évaluation des performances d'un mur guideau associé à des exutoires de surface visant à assurer la dévalaison sans dommage des smolts de saumon atlantique a été menée à la centrale hydroélectrique de Tuilières sur la rivière Dordogne dans le Sud-Ouest de la France. Cette étude, au cours de laquelle 603 smolts ont fait l'objet d'un suivi par radio télémétrie, avait pour objectifs i) d'évaluer les taux d'échappement (passages par d'autres voies que par les turbines) ii) d'analyser le comportement des smolts devant les ouvrages ainsi que (iii) l'évolution de la perméabilité du masque de guidage en fonction des conditions de débit turbiné et de débit déversé au barrage. Le taux d'échappement par les exutoires a varié de 15% à 85%. Le débit turbiné est le facteur principal influant sur l'efficacité du mur guideau. L'apport des exutoires secondaires, s'il est notable pour les faibles débits turbinés, diminue fortement avec l'augmentation de ces débits. Les poissons arrivent en grande majo