In geophysics, the Saint-Venant system has been the cornerstone of studies involving gravity driven flows. Even if the Saint-Venant system has been extended to treat arbitrary topographies, complex rheology fluids,... it fails to represent complex flows such as stratified flows, non-hydrostatic effects,... During this presentation, we propose - a model approximating the 3d hydrostatic Navier-Stokes equations, - a non-hydrostatic extension of the Saint-Venant system. For both of them, we propose a kinetic interpretation and a robust discretization technique endowed with properties such as positivity, well-balancing and fully discrete entropy inequality. Several applications concerning hazardous flows and sustainable energies (buoys and microalgae culture) are given.