Mechanisms underlying the dynamic evolution of an open-coast tidal flat-creek system: I: physical model design and tidal creek morphology

To deepen the understanding of the dynamics underlying tidal creek evolution, a reduced-scale physical model was established based on the prototype of muddy silt tidal flat-creek system on the central Jiangsu coast. Driven by tidal currents, the evolution of tidal creeks was simulated starting from initial uniform bed level to a dynamic equilibrium state, and the morphology of tidal creeks was analyzed. The results showed that the tidal creek system developed with a sharp and later a smooth increasing rate. Finally, the tidal creek system achieved a dynamic equilibrium state. The development stages of the tidal creek system could be evaluated with two methods. The first index was the ratio between the total length of the tidal creek system in different experimental stages and the total length at the dynamic equilibrium state. The other was the comparison between the elevation-changing rate of tidal creeks and its adjacent tidal flat at each experimental stage. When the dynamic equilibrium state was reached, the number of ordered tidal creeks kept a substantially constant proportion in comparison to the total number of tidal creeks. The width, depth and the width-to-depth ratio of tidal creeks were in line with a lognormal distribution. It showed a power function exists between the width and the width-to-depth ratio, as well as the depth and the width-to-depth ratio.