NUMERICAL MODELING OF THE FLOW ON A DAMAGED WEIR APPLICATION TO THE CAVAILLON RIVER, HAITI

Carlier d'Odeigne, Olivier [UCL] Zech, Yves [UCL] Soares Frazao, Sandra [UCL]

Haiti is one of the most vulnerable countries to floods and inundations. The development of infrastructures enabling systematic river monitoring is quite inexistent and consequently hydrologic and hydrographic data are really scarce. In the frame of an academic cooperation project aiming at enhancing the local capabilities to manage Haitian rivers, the Dory weir is studied because it will be used as upstream boundary condition for further flow simulations. However, due to past severe flow conditions, the weir is seriously damaged and is no more working in standard conditions. So, three different approaches are used to re-build a stage-discharge relation. Recent floods in May 2016 have recorded a set of water level and river discharge measurements. Added to previous field campaigns, these form a first estimate of stage-discharge relation. Then, detailed numerical simulations using OpenFoam are used to generate several flow scenarios on the weir, considering its exact damaged geometry, in order to rebuild a local stage-discharge. The added value of this detailed numerical approach is discussed by comparing a simple approach in defining an equivalent standard profile from which the stage-discharge relation. The objective of establishing a proposition for a stage-discharge relation from numerical approach is completed. Even if some of this approach could be further improved, the OpenFoam model can be easily adapted to other similar applications and researches including the integration of a specific shape or topographic surface. The most important benefit of the present work is therefore the establishment of a numerical-based reproducible method to generate stage discharge relations from real topographies that could, as in Dory’s case, be deteriorated and differ from standard shapes.