Focus on the Methods of Fluvial Migration Architecture

The migration architecture of the rivers has a significant influence on a wide range of disciplines. For example, the Geomorphology, the hydraulic, the climate, hydrologic and topographic characteristics and so on. Previous studies relating to the issue of fluvial migration include the literature of river channel patterns [1,2], deposition transport and grain size sorting [36], bend meandering processes [7-15], hydraulic characteristics [4,16], climate change [17], flow resistance and bank erosion [18,19]. With the new technological developments during the 21st century, an increasing number of studies intending for the deep understanding of migration theories of meandering rivers have been published [20]. In the recent years, increasingly studies have tended to discover new ways towards the meandering process of rivers. Latest methods like Google Earth, ACME, and ADCP are gradually developed to complete the task. For the purpose of regulating the fishery, even the fishermen focus on the time and cause of migration of rivers [21]. The methods of fluvial migration have also been the subject of intensive research in order to explain the evolution and mechanism of formation of the sinuous rivers. From the initial empirical models [15,16,18,22,23] to the process-based quantitative research [20,24-26], from the field outcrops [18,19] to the modern analogs [8,27,28], extensive advances have been obtained. The fluvial migration of point bars has been recently revealed by some researchers. Ghinassi & Ielpi [8] discussed the architectural and sediment logical features of Downstream-migrating fluvial point bars (DMFPB) from the perspectives of outcrops, borehole, and 3D-seismic datasets. And different modes of meander-bend transformation have also been discussed by studies [9,10,12,15,29]. However, different approaches illustrated various limitations, such as the morphology models proposed are limited to steady-state conditions [30]. Some models lose sight of the influence of bank erosion [15], vegetation, the relation between channel width and depth [31]. Though various migrating models are proposed, the nature of the change of channels has remained a huge challenge. Brice [15] proposed the four main categories of loops (simple symmetrical, simple asymmetrical, compound symmetrical, and compound asymmetrical); Parquer [32] pointed out that how the channel migration could be correlated with morphological parameters. Thus it is essential to take a look back to the methods for studying the fluvial migration process since it is difficult to understand and may get different answers by different methods (Figure 1). This review has attempted to address the development and advance of methods and intends to promote the understanding of migration architecture of rivers.