The Campotto Valleys are what remains of the ancient Argenta and Marmorta Valleys and began to form from the 12th century, when the Po di Primaro, by then hanging and cluttered with sediment, could no longer receive water from the various Apennine streams that flowed here. Today the valleys, acting as expansion reservoirs, are used during floods to receive water from the lower Bolognese plain and then be subsequently discharged, through weirs and water pumps, into the Reno River.

They are divided into three compartments: Cassa Campotto and Bassarone has a series of freshwater valleys and channels for flood control and numerous trails both freely accessible and with a guide. Valle Santa is characterized by emerged vegetation, including extensive reedbeds and water lily laminations; nearby is a wet meadow that is an ideal nesting and resting place for numerous bird species. Bosco del Traversante constitutes one of the last patches of hygrophilous forest in the Po Valley: in this environment, in fact, both impressive shrub and tree associations grow periodically in contact with water.