IN PICTURES – In the heart of the fish passage of the Mauzac-et-Grand-Castang dam

0

The migratory fish, such as Atlantic salmon, are born in the Dordogne, leave for the ocean for a few years and then return to the river. The course becomes more complicated when you have to swim upstream and dams now punctuate the Dordogne.

Germinal Peiro, president of the department, welcomed the construction of the building, two years after its commissioning. © Radio France
– Lisa Guinic

The new Mauzac-et-Grand-Castang fish pass, near Lalindelaunched on June 17, 2020, was inaugurated this Thursday, September 15, 2022 – after two years of the Covid-19 epidemic.

To view this Facebook content, you must accept cookies Social Networks.

These cookies make it possible to share or react directly on the social networks to which you are connected or to integrate content initially posted on these social networks. They also allow social networks to use your visits to our sites and applications for the purposes of personalization and advertising targeting.

Manage my choices

Pass the obstacle of the dam

The purpose of the fish pass is to “get the fish over an obstacle”begins Thomas Régnier, environmental engineer at EDF Hydro, organization behind the building. “The drop height [du barrage] prevents fish from move from downstream to upstream [de la rivière]“he adds.

30,000 fish can use the pass to go up the Dordogne during the migratory period.
30,000 fish can use the pass to go up the Dordogne during the migratory period. © Radio France
– Lisa Guinic

The professional compares the fish pass to “a kind of stairs”. “Its steps are calculated so that, hydraulically and biologically, they correspond to the swimming ability of all fish.”

22 pools

From bleaks of 10 cm to catfish of 2.20 m, passing of course by the great migrants, such as salmon, shad and lamprey. 22 multi-species ponds were thus created on the right bank of the dam to cover the six meters drop of the Dordogne.

The fish pass analysis room opens its door, at river level.
The fish pass analysis room opens its door, at river level. © Radio France
– Lisa Guinic

The spectacle becomes even more striking, under the feet. Yohann Bappel, from the Migado association, Migrateurs Garonne Dordogne Charente Seudre, invites visitors to descend a steep staircase to admire the fish pass at water level. He calls her affectionately “the bunker”.

Yohann Bappel, from the Migado association, in his "bunker".
Yohann Bappel, from the Migado association, in his “bunker”. © Radio France
– Lisa Guinic

fish count

“The peculiarity of this passexplains Yohann Bappel, head of control stations for the Dordogne team : two windows and two video acquisitions different. The top camera films the entire window and the bottom camera is much more precise, with high magnification. Yohann Bappel thus counts, each day, the number of fish going up the Dordogne through the pass.

Visitors, if they are lucky, may see fish crossing the pass.
Visitors, if they are lucky, may see fish crossing the pass. © Radio France
– Lisa Guinic

As a simple visitor, the “bunker” inevitably impresses. Pauline, 23, is accessing this place for the first time. She is struck by “the immensity of the infrastructure, the flow of the passing water, etc.” During the migratory period, towards the end of spring, up to 30,000 fish can pass through this pass during the day.

4.5 million euros of work

Florent Farge, mayor of Mauzac-et-Grand-Castang, is “happy to see the work working”. “Biodiversity is extremely important at presentcontinues the aedile. We know that this technological work of art Is usefull.” The work to build this new fish pass was entirely carried out by EDF Hydro. They represent 4.5 million euros of investment.

The artist Jean-François Noble created a fresco to accompany the salmon and other species on their way up the Dordogne.
The artist Jean-François Noble created a fresco to accompany the salmon and other species on their way up the Dordogne. © Radio France
– Lisa Guinic


source site-38