We consider a 1-D tank containing an inviscid incompressibleirrotational fluid. The tank is subject to the control which consistsof horizontal moves. We assume that the motion of the fluid is well-described by the Saint–Venant equations (alsocalled theshallow water equations). We prove the localcontrollability of this nonlinear control system around any steady state.As a corollary we get that one can move from any steady state to any other steady state.