Section: Application Domains

Hydrology and River Hydraulics

Participant : François-Xavier Le Dimet.

Water resources and floods are critical issues. They are the result of complex interactions within the water cycle between meteorology, hydrology and hydraulics. Mathematical and numerical modelling is becoming accepted as a standard engineering practice for prevention and prediction.

Concerning river hydraulics, forward models based on 1-D and 2-D shallow water equations and the corresponding industrial softwares (e.g. Telemac2D, Carima1D) are satisfying for many situations. Nevertheless for real applications, initial and boundary conditions (basically, water level and discharge) are very partially measured hence difficult to prescribe. Empirical parameters (e.g. land roughness) are calibrated manually with difficulties. Also, coupling between 1D net-model and local 2D configurations is a priori not feasible using the standard computational softwares.

Concerning soil infiltration and rainfall-runoff phenomena, on one hand forward models have still to be improved (e.g. 3D Richards' equations), and on the other hand, empirical parameters are numerous and very difficult to prescribe.

Realistic and reliable numerical prediction requires an integrated approach with all components (different models coupled together and corresponding measured data), with affordable computational cost. Sensitivity analysis and data assimilation methods, that have shown their potential in other geosciences like meteorology and oceanography, are now in the forefront in hydrology: [3] , [37] . This prediction chain is far from being operational in hydrology and river hydraulics.

The problems addressed in MOISE are related to the coupling/superposition of models, more efficient forward solvers, sensitivity analysis and data assimilation for catchment scale hydrology and/or river hydraulics.