We present numerical simulations of the Saint-Venant system for shallow waters, including small friction and viscosity, motivated by the interest in recovering the results of experimental studies on the free-surface flows over an obstacle. We use the kinetic scheme "with reflections" formulated in [B. Perthame, C. Simeoni, A kinetic scheme for the Saint-Venant system with a source term, Calcolo, 38 (2001), no. 4, 201-231], appropriately extended to obtain second order accuracy according to the theory developed in [Th. Katsaounis, C. Simeoni, First and second order error estimates for the upwind source at interface method, Math. Comp. 74 (2005), no. 249, 103-122]