Salt marshes are often dissected by a network of channels formed by tidal oscillations and related water fluxes. In this note we present a stochastic model able to simulate the formation and evolution of tidal networks in salt marshes. The model is based on a simplification of the shallow water equations that enables the determination of the water surface gradients on the marsh platform and related bottom shear stresses. The governing equations are then solved with a random walk algorithm in an enclosed domain representing the marsh platform and its physical boundaries. Model results show how the development of the network depends on the tidal forcing, the critical shear stress for erosion, as well as the local heterogeneities in vegetation and sediment substrate.