Safe and fast passage requires an efficient and effective levelling system and process. The Deltares Lock Facility can be used to test different designs for levelling systems, including the associated forces exerted on the vessels in the lock chamber. The effects of density currents in sea locks can also be examined. Deltares combines the results of these scale model tests with the results of calculations with computer models. This allows for the sound comparison of different levelling systems and optimisation of the design and structure.

Areas of application

Large vessels have to be able to pass through a lock smoothly and safely. This means that the filling and emptying of the lock chamber should be completed as quickly as possible, minimising the delay for shipping as much as possible while limiting the forces on the moored vessels. A range of levelling systems and levelling scenarios can be tested in the Lock Facility, measuring the resulting hydrodynamic forces on the vessel. In addition, the flow velocities near the bottom can be measured, providing input for the design of measures to protect the bottom against possible scour. These results can be used to optimise the levelling system and the levelling process.
Safe and smooth passage using a scale model in combination with computer models
In parallel with research looking at physical scale models in the Lock Facility, Deltares develops computer models to simulate specific processes in locks. In this way, the forces on the vessels generated by the levelling process can be simulated with LOCKFILL and water exchanges caused by density flows can be simulated with WANDA-Locks (both 1D mathematical models). In addition, detailed three-dimensional flow calculations (CFD) are used to simulate the flows in the physical scale model and the situation in the field. The results obtained with the physical scale model are used to validate the numerical models with the aim of establishing a well-calibrated modelling toolbox that can be used to evaluate different hydraulic conditions.


The conceptual design for the levelling system in the new IJmuiden sea lock laid the foundations for the Deltares Lock Facility in 2014.
Typical studies in the Lock Facility relate to:

  • Navigation locks: determining the achievable levelling times and acceptable flow velocities. Different levelling systems have been tested such as openings in the lock gates, short lateral culverts and long longitudinal culverts with bottom grids on the lock floor (e.g. New Sea Lock in IJmuiden, New Lock in Terneuzen);
  • Salt intrusion: study of the flow patterns around the salt screen used to selectively withdraw salt water near the new lock in IJmuiden.

Technical specifications

The facility has a lock section and two adjacent approaches with a total area of approximately 60 m x 20 m. In addition to standard instrumentation for measuring discharges, water levels, forces and densities, advanced measurement techniques such as PIV (Particle Image Velocimetry) and PTV (Particle Tracking Velocimetry) can also be used to obtain detailed flow fields.

  • Size of facility: 60 m x 20 m
  • Maximum water depth: 0.70 m
  • Scale between 1:40 and 1:30
  • Measurement of water level, density, pressure, discharge, flow velocity, temperature
  • Measurement of forces on the vessel in three directions
  • Cameras for flow visualisation (top view, side view)
  • Advanced measuring techniques (PIV, PTV) for detailed flow patterns
  • Brine storage and salt mixing tanks
  • Underground reservoirs for storage of salt water and freshwater
  • Maximum pumping capacity: 400 l/s
  • Different types of vessel e.g. bulk carriers, container vessels
  • Data acquisition system and steering software for the scale model

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