2D sonar techniques for monitoring the canal bed morphology of entrances to navigation locks

Navigation locks are essential components of inland waterways. They enabling vessels to traverse sections with differing water levels. These structures are increasingly vulnerable to damages caused by (1) scour i.e., erosion of sediment due to natural water flow and ship-induced currents, and (2) sediment or debris obstructing lock gates. Scour-induced damage threatens the structural integrity of locks, leading to costly maintenance, prolonged closures, and economic and environmental consequences. Traditional monitoring methods, including visual inspections and fixed instrumentation, are often hampered by water turbidity, high costs, and susceptibility to debris damage. Sonar technologies provide a non-invasive, cost-effective alternative for detailed underwater imaging, even in challenging environments. This paper explores the application of 2D sonar imaging for monitoring navigation lock approaches, with a focus on bed morphology and scour progression. Using the Prinses Beatrix Lock in the Netherlands as a case study, the paper demonstrates the effectiveness of 2D sonar systems in (i) detecting morphological changes such as scour and sediment transport from bed protection layers and (ii) estimating ship drafts. The findings underscore the importance of integrating sonar-based structural health monitoring systems to extend the lifespan of navigation locks, enhance safety, and optimize maintenance strategies for aging waterway infrastructure.