  Experiments on streams of water flowing down a rigid substrate have been
performed for various plate inclinations and flow rates, and we focused on the
regime of stationary meanders. The outcome is that (i) the flow is highly
hysteretic : the shape of the meanders varies with flow rate only for
increasing flow rates, and the straight rivulet regime does not appear for
decreasing flow rate. (ii) A simple force balance, including inertia, capillary
forces, and also hysteresis of wetting, accounts well for the experimental
instability threshold flow rate and for the final radius of curvature of the
meanders.
