Addressing the challenges in the Yangtze River waterway regulation projects,where frequent monitoring of submerged dam cross-sections is required and structures are significantly influenced by the hydrological cycle of“deposition during rising water and scouring during falling water,”the conventional fixed-cross-section monitoring method often falls short due to its limited coverage.This limitation hinders accurate assessment of section compliance rates and comprehensive evaluation of scouring trends.To enhance the precision and scientific rigor of construction acceptance and flood season safety monitoring,a comparative and applied study of monitoring methods is conducted,focusing on both section acceptance and scouring assessment.Based on two typical regulation project cases,a comparative analysis is performed using the triangle network volume surface method alongside the traditional fixed-cross-section method.The results indicate that compared with the traditional method,the triangle network volume surface method analysis,by constructing a high-precision 3D digital model,achieves 100% comprehensive measurement of the dam and its surrounding riverbed morphology.This allows for more precise detection of localized non-compliant points,scouring pits,and siltation bodies that are missed between traditional fixed sections,along with their spatial distribution and volumetric changes.Consequently,this method provides powerful scientific data support for the detailed acceptance of construction quality,accurate prediction of scouring dynamics during flood seasons,and the formulation of protection and reinforcement plans,thereby effectively ensuring the long-term stability and safe operation of the regulation structures through flood periods.