Dam break inundation mapping is essential for risk management and mitigation, emergency action planning, and potential consequences assessment. To quantify flood hazard associated with dam failures, flooding variables must be predicted by efficient and robust numerical models capable to effectively cope with the computational difficulties posed by complex flows on real topographies. Validation against real-field data of historical dam-breaks is extremely useful to verify models’ capabilities and accuracy. However, such catastrophic events are rather infrequent, and available data on the breaching mechanism and downstream flooding are usually inaccurate and incomplete. Nevertheless, in some cases, real-field data collected after the event (mainly breach size, maximum water depths and flood wave arrival times at selected locations, water marks, and extent of flooded areas) are adequate to set up valuable and significant test cases, provided that all other data required to perform numerical simulations are available (mainly topographic data of the floodable area and input parameters defining the dam-break scenario). This paper provides a review of the historical dam-break events for which real-field datasets useful for validation purposes can be retrieved in the literature. The resulting real-field test cases are divided into well-documented test cases, for which extensive and complete data are already available, and cases with partial or inaccurate datasets. Type and quality of the available data are specified for each case. Finally, validation data provided by dam-break studies on physical models reproducing real topographies are presented and discussed. This review aims at helping dam-break modelers: (a) to select the most suitable real-field test cases for validating their numerical models, (b) to facilitate data access by indicating relevant bibliographic references, and (c) to identify test cases of potential interest worthy of further research.

The capability of a GPU-parallelized numerical scheme to perform accurate and fast simulations of surface runoff in watersheds, exploiting high-resolution digital elevation models (DEMs), was investigated. The numerical computations were carried out by using an explicit finite volume numerical scheme and adopting a recent type of grid called Block-Uniform Quadtree (BUQ), capable of exploiting the computational power of GPUs with negligible overhead. Moreover, stability and zero mass error were ensured, even in the presence of very shallow water depth, by introducing a proper reconstruction of conserved variables at cell interfaces, a specific formulation of the slope source term and an explicit discretization of the friction source term. The 2D shallow water model was tested against two different literature tests and a real event that recently occurred in Italy for which field data is available. The influence of the spatial resolution adopted in different portions of the domain was also investigated for the last test. The achieved low ratio of simulation to physical times, in some cases less than 1:20, opens new perspectives for flood management strategies. Based on the result of such models, emergency plans can be designed in order to achieve a significant reduction in the economic losses generated by flood events.

Laboratory experiments of dam-break flows are extensively used in investigations of geophysical flows involving flood waves, to provide insight into relevant aspects of the physics of the process and collect experimental data for validating numerical models. A dam-break flow is a typical example of a highly unsteady free surface flow with high reproducibility. Indeed, dam-break experiments can be repeated several times under the same test conditions obtaining large amounts of different types of data (possibly using various measuring techniques) that can be combined in a single rich dataset. Moreover, laboratory tests on dam-break flows are widely considered a valuable benchmark for the validation of numerical models, since field data from historical events are scarce, sparse, and highly uncertain. However, no systematic review of laboratory investigations of dam-break flows and existing related datasets are available in the literature to provide a comprehensive overview of the test conditions considered, the measuring techniques used, and the experimental data collected. This review article aims to fill this gap, focusing on laboratory tests in schematic and idealized setups with a fixed, non-erodible bed. In particular, this review aims to help researchers and modelers to: (a) select the most appropriate laboratory tests for validating their numerical models; (b) facilitate access to databases by indicating relevant bibliographic references; (c) identify specific challenging aspects worthy of further experimental research; and (d) support the development of new or improved technologies for the mitigation of the impact of dam-break flood waves. The references reviewed are organized into tables according to the purposes of the laboratory investigation, and comprehensive information is provided on test conditions, datasets, and data accessibility. Finally, suggestions for future experimental research on dam-break flows are provided.

The numerical simulation of transient mixed flows requires suitable mathematical models that must be validated by comparison with experimental data. For this reason, a simple benchmark test case is proposed in this paper. A laboratory study was carried out in a circular conduit, specifically designed to induce a strong pipe filling bore and repeated regime transitions following the sudden opening of an internal gate. No gates or weirs were installed at the pipe ends, and ventilated conditions were guaranteed. Measurements of both pressure head and velocity are provided as supplementary material. The test case was simulated by using two finite volume shock-capturing schemes: a classic Preissmann slot model, and a recent two-equation model. In both cases, numerical results are in good agreement with experimental data, despite the low pressure wave celerity assumed to minimize spurious oscillations. When realistic celerity values are adopted, the two-equation model appears to be more robust in handling flow regime transitions.