Parameterizing the Yellow River Delta tidal creek morphology using automated extraction from remote sensing images

The tidal creek is an important part of the intertidal zone, which maintains the balance between depositional processes and a given hydrodynamic environment. Much can be inferred about the development and evolution of a tidal creek by examining its morphometry characteristics; this information can also provide scientific decision support for the development and utilization of coastal tidal flats. In this study, we propose a complete system of large-scale tidal creek morphometry characteristic extraction algorithms. This system improved the intelligence of the node classification and the accuracy of the grading, as well as mitigates the interference of island-shaped tidal creeks in the automatic iterative classification process. And this system solves the problem of low post-processing efficiency due to the existence of a large number of discontinuous tidal creek arcs, and greatly reduces the error in the calculation of morphology characteristics. After accuracy verification, using this algorithm, the classification accuracy of tidal creek nodes is 92.22%, and the order and flow direction information of nearly a thousand tidal creeks can be quickly and automatically defined, and the classification is error-free. The whole process is fully automatic, and it is better than previous algorithms in terms of efficiency and accuracy. It's greatly improved. After quantifying tidal creek morphometry characteristics such as the order, number, length, sinuosity ratio, bifurcation rate, and density, we identified the factors that affect the development of the tidal creek network with respect to its seawater intrusion and vegetation distribution. Our conclusions are as follows: (1) The order and number of the tidal creeks increase from north to south and from west to east. And the average length of the tidal creek increases with the order of the tidal creek. The sinuosity ratio of the tidal creek on the land side is greater than that on the sea side. The density of the order 4 tidal creek system is greater than other tidal creek systems. The differences in these characteristics are mainly related to vegetation distribution and seawater erosion. (2) Seawater erosion promotes rapid changes in the tidal creek sinuosity ratio, bifurcation rate, and density. However, due to the shrinkage of the tidal flat catchment area, the rate of change of the tidal creek morphology characteristics has slowed. However, excessive erosion has narrowed the tidal flat catchment area, resulting in a slowdown in the variation of tidal creek morphology characteristics. The changes in the morphology characteristics of the tidal creeks on the west side of the Old Yellow River Estuary are affected by seawater erosion, showing obvious stages: various morphology characteristics increased rapidly before 2016, and the growth rate slowed after 2016. (3) At present, due to the vegetation gathering on the northern and southern sides of the Yellow River estuary, most of the tidal creeks have achieved equilibrium. The bifurcation ratio of the tidal creek system at all orders showed an increasing trend, but the increasing rate slowed down, from large-scale bifurcation to local etching. Our algorithm represents a significant step forward in the high-precision quantitative detection of tidal creek morphology characteristics, and our results provide evaluable insight into the necessity of monitoring the status and evolution of tidal flats.