How to breach the dam: Formulating guidelines for the design of dam breach experiments

Flood protection remains a major global challenge, particularly for low-lying countries such as Belgium and the Netherlands. The design of safe riverine and coastal areas involves the construction and maintenance of protective structures such as dams and dikes. According to the International Commission on Large Dams (ICOLD), there are approximately 62,000 dams worldwide (ICOLD, 2025). However, these structures face increasing threats from climate change. In riverine areas, higher river discharges and more frequent dam overtopping events are likely to occur due to more intense precipitation events. In coastal areas, sea level rise and an increased number of storm events could threaten the current state of dams and dikes. Dam failure can result in significant losses of human lives, economic and environmental consequences. The magnitude and extent of these losses are influenced by the rate of dam breaching (Wahl, 1998; Yochum et al., 2008). Among the 36,000 large dams listed in the ICOLD database, approximately 300 failure incidents have been reported. A thorough investigation of ICOLD, United States Cold Storage (USCOLD), Australian National Committee on Large Dams Incorporated (ANCOLD), and other databases showed that overtopping is responsible for about 48.4% of dam failure up to 1986 (Foster et al., 2000).
Breach formation and development in dams is a complex and dynamic process. Experiments on overtopping dam breaching are essential for improving our understanding of these processes and for supporting the development, calibration, and validation of numerical models. While laboratory experiments on overtopping dam breaching have been conducted under different conditions, challenges persist in standardizing experimental designs and ensuring their compatibility with numerical modelling.