Dam removal on the Isaby river to open this tributary of the Gave de Pau for brown trout and Atlantic salmon.
The Isaby is an 11 km long river in the Hautes-Pyrénées department, France. It is a well-preserved tributary of the Gave de Pau, classified as Natura 2000 (FR7300922), and is home to numerous threatened species such as Atlantic salmon, Pyrenean desman and European otter.
This stream can play a very important role for these species, which are also present in the Gave de Pau, but the dam limits the possibility of exchange between the Gave de Pau and the Isaby.
| Project status | Live |
|---|---|
| Project type | Dam removal: demolition |
| Country | France |
| River | Isaby |
| Removal date | October 2025 |
| Km to be opened | 10 km |
| Focal species | Atlantic salmon, brown trout |
| Organisation | Fédération Départementale des Associations Agréées pour la Pêche et la Protection du Milieu Aquatique des Hautes-Pyrénées (FDAAPPMA 65) |
| Website | peche65.fr |
Since 1917, the salmon population in the Gave de Pau has been almost completely wiped out due to the construction of dams. However, this is a key area for salmon, with favourable habitats. Over the past 20 years, efforts have been made to restore the salmon population, yielding very encouraging results.
Restocking and significant work to improve ecological continuity along over 140 km of the Gave de Pau have enabled salmon to return to spawn at the confluence with the Isaby stream.
This project is also an opportunity because the owner is sensitive to environmental protection and restoration.
The dam removal will free up 10 km of the main river upstream and 4 km of tributaries, which are highly favourable to salmon and brown trout.
Dismantling the dam will improve hydromorphological conditions in the downstream river sections which are currently suffering from a significant sediment deficit. It will also help to lower water temperatures in warm months.
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