The "backpack water wheel"
The small water wheel is put in the backpack before the trip and put together during the break at the stream. No glue is needed because as soon as the water wheel is dipped in water, the wood swells and the parts stick together firmly. Now it will soon be burbling in the stream between two forks in the branches or on suitable stones as a rest. Before setting off for home, the water wheel is taken apart again and the wooden parts are left to dry for the next trip.