River's guide to Swiss contains only selection of the best
parts from this country. The swiss rivers are mostly navigable all the year round,
because the rivers have water from a glacier, but the water is very cold. I
advise to use a good raft, a helmet, a cork jacket and a neopren.
The diffuculty is only informative by virtue of my experiences. I recommend
to scout rivers from a bank, because the rivers often traverse by a dangerous gorge
with forceful drop.