100 years back, building dam lakes was state-of-the-art to protect settlements from flooding and to produce electrical energy. What was not completely known (or thought after) at this time was the necessary amount of stones as bedload that the downstream parts of the river now were deprived of. Calculations indicate that 40.000 metric tons would be necessary to prevent the erosion down-river. Parts of that amount were continuously excavated from the lake for building purposes, but the bigger amount filled up the basin. Now they are rebuilding the retaining weir to accomodate better for the bedload transport, but it remains to be seen how much the residual flow – the bigger amount of water goes to the power plant – is able to move. The power plant itself is one of the really beautiful historical buildings, up to this time almost in original condition outside
At the risk of sounding repetitive: this is another great diptych. Well seen and nicely executed. I am really enjoying these.
Thanks, Cedric! I take this as an encouragement to continue this path.
This is rather interesting, at least nothing I have run into here in Finland, but then I don’t know much about rivers and dams, and our terrain is so flat that there aren’t that many places where water is able to transport stones. But selective transport of sediments of course occurs. It used to be that peatlands were converted into forests and farmland via ditches, and that affected the flow of water. Nowadays peats are harvested for energy, another thing that changes the flow of water.
Yes, Juha, Finland is really rich with natural ressources (especially in relationship to the small number of people), and so you are lucky to find big areas where the human influence on the shape of the landscape is still small. The art is to keep change in a scale and at a speed that will not create irreversible effect under which our children and grandchildren have to suffer.