Overtopping is the most common cause of failure in recent dams beyond the fact that embankment dams totalize about 3/4 of the 33 105 large dams worldwide, corresponding 88% to earth dams and 12% to rockfill dams (ICOLD 2003). Therefore, the main objective of the project is to perform laboratory investigations to understand the mechanics of soil erosion and particle motion in the embankment, to allow the calculation of the resulting discharge hydrograph and in general, to improve the current ability for reliable prediction of breach formation by overtopping and its evolution in earth embankment.
Dam and levee failure by overtopping have been object of several laboratory studies which allowed the production of useful data, namely discharge hydrographs for model validation. However these studies failed to produce detailed phenomenological information on the breaching process, especially in what concerns the description of the geotechnical discrete failure episodes during the breach evolution and the interaction between hydrodynamic erosion and geotechnical failure (Wahl 2004).

In this context, the current ability to predict effluent flow discharge hydrographs is limited and full of uncertainty since the phenomena involved in the morphological evolution of the breach are not yet sufficiently understood. Therefore, there is an evident need for prediction tools to assess the flood impacts in river floodplains following levee or dam failure.

This project encompasses the pursuit of an extensive and systematic laboratorial test program to characterize the failure mechanism of earth embankments and the following effluent hydrographs. This will improve the current capacity to produce reliable predictions of the breach formation and evolution following the failure by overtopping of earth embankments.

The methodological proposal comprises three main stages: 1) theoretical, in which a theoretical framework is developed to guide the empirical work; 2) laboratorial, in which data is collected for the empirical characterization of the main hydrodynamic and geotechnical phenomena and 3) computational, in which a discretization technique and a solution procedure are devised.

The project will assure national on-going research and will strength and enhance the partnership with international research teams by additional external funding as it will also be an important instrument of a broader international research effort that includes others international on-going projects. Ultimately it represents an effort to engage both academy and end-users in the production of tools for risk management concerning dam and levee failure. The fundamental objective, to improve current ability to reliably predict breach formation through embankments, is, in itself, an academic objective, but it is also meant as a contribution for society’s sustainable development.