Stream bed stabilization using boulder check dams that mimic step-pool morphology features in Northern Italy

During the last 10 years, the check dams made of boulders have been fully employed for torrent management, particularly for high-gradient stream stabilization. The analysis of this typology is shown in relation to three aspects: building features, field of use and design according to geomorphologic principles. The “Maso di Spinelle” torrent located in the Province of Trento, Italy (North Italian Alps) is an example where a sequence of low-check dams made of boulders have been used for bed stabilization. The design criteria are taken from the step–pool morphology features and the results are encouraging for further applications. The artificial step–pool grade-control structures in the Maso di Spinelle torrent have been successfully tested by floods events with return periods of about 7–10 and 20–25 years.