New ecological concepts for the refurbishment of large hydro-power stations

This article discusses how new ecological concepts are applied when renewing large hydropower stations. Two examples are given of such renewal schemes on two major Swiss rivers - the Aare and the Rhein. The chances offered by the necessity to renew such installations are looked at. In particular, the ways in which the disadvantages of the original power stations with respect to ecological factors are discussed. These include the installation of fish-passes and ways and means of guaranteeing minimum quantities of water in the old river bed. The new hydropower stations are described and figures on their technical equipment are presented, along with information on the almost natural conditions guaranteed in the old river beds