Abstract:

Accurately predicting the development trend of river patterns and leveraging their advantages is a prerequisite for ensuring stable river function. After the operation of the Three Gorges and other reservoirs, the continuous long-term erosion of channels in the middle and lower reaches of the Yangtze River and the drastic adjustments of local river regimes may lead to river pattern transformation. Such transformation will have a series of impacts on river functions such as flood control, ecology, water supply, and navigation. This paper reviews the causes, classification and discrimination, river pattern transformation mechanisms, evolution laws, and prediction methods of different river patterns in the middle and lower reaches of the Yangtze River under long-term erosion. It also scrutinizes the impacts of river pattern transformation and corresponding governance strategies. On this basis, several directions for future research are proposed: the refinement of river pattern subcategories, the responses of shape parameters of different river patterns to changes in water and sediment conditions under discontinuous constraint boundaries, effects of longitudinal erosion adjustment of long channels on river pattern transformation, the quantitative identification of critical conditions for river pattern transformation, and prediction methods for century-scale river pattern transformation as well as trend estimation.

Key words: river pattern, evolution regularities, driving mechanism, prediction methods, governance measures, middle and lower reaches of the Yangtze River