It is a park covering approximately 2,200 hectares on the outskirts of Lyon, extending over most of the island. It was created in the 19th century with aqueducts to help control the flooding of the Rhône River. The park is a recreational area for the residents, and also includes protected areas for wild animals and plants. The place is also a source of backup drinking water for Lyon, and the place also provides a buffer flood zone in case the Rhone floods.