Application of Norbit iWBMS integrated multi-beam system for underwater topographic survey in Yangtze Estuary hazardous reaches

The Yangtze Estuary is China′s largest tidal-river coupled estuary, where underwater topography in critical sections changes dramatically, creating an urgent demand for high-precision, full-coverage, and high-efficiency bathymetric technologies in these areas.Traditional single-beam systems are inefficient, while conventional multi-beam systems involve complex installation and exhibit blind zones in complex terrains, making them inadequate for monitoring requirements.This study introduced the Norwegian Norbit iWBMS integrated multi-beam system and selected two typical critical sections, the scour area near the piers of the Sutong Bridge and the waterfront of Taicang Port, for synchronous comparative measurements with the Danish Reson SeaBat 7125 system.The accuracy and reliability of the Norbit system were evaluated from internal consistency, external consistency and engineering feasibility three dimensions.The study demonstrated that the Norbit iWBMS could achieve underwater topographic surveying with "equivalent accuracy, high efficiency and full coverage" in the complex hydrodynamic, high-turbidity and strong turbulence environment of the Yangtze Estuary, providing a new technical approach for estuary management, waterway maintenance and ecological monitoring.