Comparison between 1D and 2D dam-break flood numerical models

Abstract

Numerical simulation models are powerful tools for dam and downstream valley risk assessment and management, including the evaluation of the impact of floods due to dam failure events and the valley emergency planning. Several codes are available for numerical simulations of floods caused by dam failures: the most well known being 1D models. This last type of models can lead to possible errors namely in the cases where there are important cross-section changes (like enlargements or narrowings) in the propagation river stretch or whenever the flow occupies a floodplain. In these cases a 2D model is required. The 2D BIPLAN model was developed for the simulation of dam-break flood waves in valleys with irregular topography whenever the 1D approach loose validity. This paper concerns the use of the 2D BIPLAN model and of the well-known 1D DAMBRK model for the simulation of the dam-break flood propagation in a real valley: the Arade River localized in the South of Portugal. The accuracy of both models is presented through a comparative analysis of their results with experimental data obtained in the physical model of Arade River valley. Firstly, the main characteristics of the numerical models are presented and the case study is described. Next the paper briefly describes the physical model of the case study, constructed in order to validate dam-break flood propagation models along river valleys of irregular topography. Finally, the paper also presents the results of 2D BIPLAN and 1D DAMBRK models and the comparative analysis of their results, also involving experimental data.