Well-posedness of classical solutions to the vacuum free boundary problem of the viscous Saint-Venant system for shallow waters

We establish the local-in-time well-posedness of classical solutions to the vacuum free boundary problem of the viscous Saint-Venant system for shallow waters derived rigorously from incompressible Navier-Stokes system with a moving free surface by Gerbeau and Perthame. Our solutions are smooth to the moving boundary, although the initial height degenerates as a singularity of the distance function to the vacuum boundary.