A wide network of river arms and gravel islands ...
... this is how the Tyrolean Lech presents itself to the observer. This labyrinth of gravel banks is the characteristic image of an intact wild river landscape. The gravel banks are not permanent, but transient - gravel islands disappear and emerge, river courses are relocated.

This is caused by the annual floods, during which the entire riverbed is flooded. The water masses carry away the gravel banks and deposit the gravel in another place. As the Lech repeatedly interrupts the development of vegetation and creates fresh gravel banks, these habitats appear barren. Depending on the water level, the Tyrolean Lech redeposits its gravel islands. Constant change is the only thing that really lasts in this habitat. Despite the proximity to the Lech water, a warm microclimate characterised by dryness and heat prevails on the gravel banks. Water runs off quickly through the large cavities in the ground and is hardly stored. In addition, the gravel banks are exposed to full sunlight and the hot, dry environment and constant movement of the gravel banks create an extreme location. Only specialists from the animal and plant world that have developed special survival strategies can exist here. As pioneers, they conquer this exposed habitat.