I have always been intrigued by the “dam” in Les Marécottes never really knowing what it’s function was, until after having walked around it yesterday and seeing the SBB/CFF signs and thus realizing that it belonged in part to the Swiss train system I became even more interested.
Turns out that it is a minor retention basin for the lower electrical complex in Vernayaz, one that in turn is linked to the whole Emosson hydrology complex. The dam at Emosson collects waters from several different mountains and rivers in both Switzerland and France. As the Swiss train company owns part of it, it gets it’s bit first then the remainder is divided in between France and Switzerland in equal parts.
Anyone interested in the more technical aspects (and who can read French) will find this link of great help: http://www.hydrelect.info/articles.php?lng=fr&pg=1389
All that because when I took a quick walk late yesterday afternoon I noticed that half of it was empty and the other half very low: I had to go and see and as best I could deduct they were cleaning the silt from the bottom of the basin. As this water accumulates unfiltered and by the difference in altitudes it is easy to see that there would be silt, just didn’t realize how much!
And the ubiquitous shopping trolley… no matter where one goes, there was someone to dirty the site.