Research progress on the failure mechanism of ecological slope protection under multi-factor coupling in the Lower Yellow River

The Yellow River basin is of critical strategic importance to China's economic and social development. The lower reaches are characterized by low flow rates and high sediment concentrations, exhibiting an uncoordinated water-sediment relationship. This results in a secondary-perched river phenomenon and a complex evolution of river form. The degradation of bank slopes poses a significant threat to flood control integrity and hinders the economic and social development. Therefore, the preservation of riverbank stability and the implementation of effective slope protection and risk reduction measures are essential. The degradation of ecological slopes is a complex issue, influenced by a synergy of hydrological, pedological, vegetative, and structural stability elements, regulated by intricate processes. The inadequacies of current river dynamics theories necessitate in-depth investigation on this topic. This study compiled the current state of bank erosion in the lower Yellow River, elucidated the factors contributing to slope instability, and assessed the state-of-the-art in ecological slope protection methodologies and the challenges in risk evaluation and management protocols. The study identified key directions for future research in ecological slope protection, including: unraveling the degradation processes under hydro-soil-vegetation interactions; innovating rigid-flexible ecological slope protection structures adapted for intense alluvial conditions; developing comprehensive, tiered risk assessment models for ecological slope engineering; and constructing integrated frameworks for the monitoring, evaluation, and control of riverbank slope integrity.