Swedish water rights mystery

My friends live in a house overlooking this lake, about 15 km from Gothenburg. The lake is man-made, having being created by the construction of a dam. A few hundred metres downstream from the outlet is the remains of a mill. Further downstream still, there was yet another mill; the present owner retains the rights to the flow of a certain volume of water. These rights were acquired in the 1920s, when the government (foolishly) gave away water rights in exchange for an undertaking to construct electricity generating facilities. However, this particular facility, is, I am informed, barely functioning, and even if it was, it would make little use of the head of water that is potentially available and is consequently inefficient.

In dry weather, as we have had recently, this owner complains of insufficient flow, and water then has to be released from the lake. Prolonged dry weather results in a significant fall in the water level and the exposure of unsightly areas of mud.

Loss of water leads to a deterioration in water quality, which for many decades has been managed by a fishing association which, among other improvements, has reduced the acidity of the water by regular dozing with chalk dust, resulting in a good population of fish including perch and pike.

I do not know if I have been given the full story, but the owner, despite making little or no effective use of this water, wants the local authority to pay 3 million kronor for the extinguishing of the rights to ‘his’ water from this and two other lakes. The obvious response would be to restrict the water outflow in dry weather so as to maintain the water level in the lakes, and wait for the claim for damages. If my information about the virtual non-use of this water is correct, the damages due would be 0,00 kr.

Such an inefficient capture of the energy in the water makes no sense. An efficient system would pipe the water from the upper level, which would create a pressure of 1 bar for every 10 metres drop and could be used efficiently to drive a turbine linked to a generator. Whether the volume of water available is worth the cost of installing such a system is another question, but it might be possible for the owner to have his power without draining down the lake.

There is a further issue also: the valuations of the lakeside properties for tax purposes, which is on the assumption that the lake is an amenity, which it certainly is not if the water level fluctuates, leaving expanses of mud in dry weather.