Hi, first of all, thanks a lot for comment, I am happy You liked the post and photos I shared.
This lake is on swedish borderside already but very close to Norway ;)... The size of a dam which was build there could create such lake by just stopping the water from the river - so it is possible that there was no any lake before or it was much smaller than now. This is a subject to check :).
The lake is a part of huuge system of connected hydroplants, producing electricity to whole region. I wrote little more about that in previous post. It is amazing when You imagine how huge was that project... the lake is the first bigger water storage on the way, the end of the system is located near Trondheim - around 150km from here...