A river-friendly dam? Poutès update

Hydroelectric dams may produce clean energy but they generally mess up a river.  Still, a redesigned dam in the mountains of central France might be a model for accommodating river environments with energy production.

© Richard Mounts

Since 1941, a 56-foot high dam in the upper reaches of the Allier River at a place called Poutès has generated power for Électricité de France (EDF).  For years, environmental groups argued that the dam blocked migrating salmon from reaching spawning groups and disrupted the river valley ecology by interfering with the normal flow of sediments.

EDF’s operating license expired in 2007 and environmentalists opposed renewal.  They wanted to see the dam decommissioned and dismantled, as had been done a few miles upstream at Saint-Étienne-du-Vignan (in the department of the Lozère near Naussac Lake).  On the opposite side, public officials and others pushed to preserve a source of clean energy and, along with it, the tax revenues to local communities.

Existing dam.  ©EDF

The standoff was finally resolved in July 2011 when EDF presented a new version of the dam.  This design would lower the dam to just 13 feet and would include accommodations for fish and sediments.  For the last three years, EDF has been building and testing a 1/13th scale model of the “new Poutès”; they avoid calling it a dam.  Besides redesigned fish ladders, the new installation will include special valves to be opened during high-water periods to allow sediment flow.  A lower barrier will also mean a smaller reservoir and a more natural river valley.  Currently, the water backs up for more than two miles.  When the new structure is completed, this will drop to about 300 yards.  Even with the much lower structure and freer water flow EDF expects to continue to generate 85 percent of the power current output.

Proposed dam.  ©EDF

The project is back in the news (at least in the Haute-Loire) because a public comment period opened at the beginning of this month.  The issue is still the decision by the Ministry of the Environment to grant EDF a new 50-year operating license.  At the beginning of January, residents in the 26 small communities along the affected portion of the river all received a brochure with information about the project and how to submit opinions.  This time, given support among all the previously contending parties, serious opposition seems unlikely.  The comment period closes on February 5 and some expect government approval within a couple of months.  EDF says it would start construction towards the end of 2016, with completion likely in about three years.