The cascading failure of check dam systems during the 28 July 2022 Emamzadeh Davood flood in Iran

In this brief communication, the authors report results from a recent investigation carried out by field surveys and remote sensing data, highlighting the role of anthropogenic factors and catastrophic failures in a series of check dams in intensifying the impacts of the 2022 Emamzadeh Davood event. A post-flood expedition was carried out immediately after the event to document the actual conditions of check dams in the region. Furthermore, optical and radar satellite images were analysed to obtain flood map and assess topography changes along the main stream.

Check dams are typical torrent structures constructed across a stream channel to diminish longitudinal slopes and curtail sediments, thereby reducing the flow speed and energy of torrential processes. However, if such structures are collapsed or partially damaged due to extreme events, poor maintenance, and/or their improper localization, the released torrent sediments from these structures can exacerbate the hydrological impact of the flood and sediment-related disasters in downstream areas, resulting in a catastrophic phenomenon similar to the failure of a landslide dam.