Experimental analysis of tidal network growth and development

In this paper we present the results of a first series of laboratory experiments carried out in a large experimental apparatus, aimed at reproducing a typical lagoonal environment subject to tidal forcings. The experiments were designed in order to improve our understanding of the main processes governing tidal network initiation and its progressive morphodynamic evolution. During the experiments we observed the growth and development of tidal networks and analyzed their most relevant geomorphic features, taking into account the role played by the characteristics of the tidal forcing in driving the development of channeled patterns. The synthetic networks displayed geomorphic features which compare favorably with those of actual networks, showing that our experimental framework proves useful for analyzing the processes governing the formation and evolution of tidal channel networks. In particular, the synthetic networks develop via headward growth driven by the exceedance of a critical bottom shear stress, and display width-to-depth ratios and seaward exponential widening in accordance with observational evidence. Furthermore experimental networks reproduce statistical network characteristics of geomorphic relevance, such as the exponential probability distribution of unchanneled path lengths.