Flood Modeling and Emergency Planning for Dam Failure: Projections in Calabria (Italy)

A dam is a hydraulic structure made of natural materials, such as earth, or artificial ones, such as concrete, whose main function is to block a watercourse to create an artificial basin with multiple purposes, irrigation, energy, flow regulation, and protection. These structures allow for the storage of large quantities of water which, in the case of a collapse, can have devastating effects on human lives and territory. Therefore, the regulations prescribe severe safety checks and provide operational guidelines for civil protection activities and emergency plans. Through some case studies in Calabria, a region of Southern Italy, the paper analyzes Italian regulations concerning scenarios where it is necessary to safely empty the reservoir behind the dam following an earthquake and allow the consequent civil protection activities and emergency plans to be defined. Also, this paper describes the coupled hydrological and hydrodynamic modeling carried out using HEC-HMS and HEC-RAS, respectively, to define three thresholds for each dam according to Italian regulations. These thresholds are the maximum flow rate for emptying the dams that are contained in the hydraulic pertinence areas downstream of the dams, the attention flow rate for the discharge of the dam beyond which hydraulic criticalities occur, and the incremental thresholds that identify scenarios with greater hydraulic criticalities.