To accommodate the 6.0 m navigation depth requirement of the Three Gorges New Waterway on the Yangtze River,a 174 km reach from Chongqing to Fengdu is taken as the research object.Based on the landform pattern of anticline-formed mountains and syncline-formed valleys in the eastern Sichuan parallel ridge-valley geomorphology,the reach is divided into alternating canyon-wide valleys and continuous wide valleys geomorphic units.This research adopts the method of combining geological analysis with quantitative verification of channel mapping to investigate the spatial differentiation characteristics and formation mechanisms of static waterway dimensions,analyzes the control mechanism of geomorphology on flow-sediment processes and flow conditions,and proposes corresponding countermeasures for waterway dimension upgrading.The results show that the adaptability of static waterway dimensions presents a significant difference of “dense in the upper reach and sparse in the lower reach”,with 99% of shallow navigation-obstructing zones concentrated in the upper alternating canyon-wide valley reach.This pattern is jointly controlled by bedrock constraints in canyon sections and deposit compression in wide valley sections,while the lower continuous wide valley reach presents generally favorable static waterway conditions.Geomorphic units dominate distinct flow-sediment processes and riverbed erosion-deposition patterns,further affecting the dynamic evolution and flow conditions of the waterway.Based on the correlation between geological geomorphology and navigation obstruction,classified regulation strategies for three channel types are put forward,providing a scientific basis for waterway construction and maintenance in the upper Yangtze River.