For the main lakes, rivers and lake outlets in Switzerland, the potentials for heat extraction and disposal were estimated by the Eawag. The methods, calculations and main results are exposed here. The potentials can be viewed on the map below: click on a lake, river or lake outlet to see the potentials for thermal use, then click on the name to see more data.
These potentials are intended to provide an order of magnitude and cannot be considered as accurate. Every waterbody is different and many specific aspects have to be taken into account for a more precise estimate.
Other older studies also estimated the potential of specific waterbodies. A summary of their findings can be found here.