The Impact of Density Differences on the Hydraulic Design of Leveling Systems: The Case of New Large Sea Locks in IJmuiden and Terneuzen

Recent constructions of large sea locks in the Netherlands at IJmuiden and Terneuzen have been accompanied by extensive hydraulic research, including physical scale model tests which took into account the effects of density differences across the lock heads during leveling operations. The case study presented here compares the situations and results from the studies of the two locations, and shows the importance of density effects in an accurate assessment of the hydrodynamic forces on the vessels and subsequently the forces on the mooring lines. Supposedly small differences in the local boundary conditions at the two locations lead to very different results, owing primarily to the differences in propagation of the density currents. Numerical models do not as yet predict this with sufficient accuracy. This further underlines the importance of doing extensive preliminary hydraulic investigations when designing large new shipping locks.