Navigation through fluid mud

There is a new, improved method for surface depth measurements through fluid mud. This results in a larger under keel clearance without any additional dredging and costs.



Fluid mud at the bottom of ports and waterways is an important factor in determining the effective depth. So far, the density of the fluid mud has been used as a key parameter to determine the nautical bottom. A completely new method for surface depth has recently been developed which also takes into account the viscosity and yield stresses of the mud, the so-called rheological properties.
The potential of the new method is enormous, since mud of a certain consistency turns out to be navigable
. This offers two opportunities: Firstly, an increase in the ships load, which is more efficient and therefore beneficial to the shipping companies. Secondly, less dredging and, consequently, a reduction in dredging costs. Less dredging also has extra advantages: less hindrance for ships and a positive impact on biodiversity in the port area.


  • Less dredging – The distance between the deepest point of a ship, the keel, and the bottom of the waterway must be kept at a minimum, the so-called under keel clearance (UKC). If mud of a certain consistency turns out to be navigable, at the same waterways less dredging is needed to guarantee the desired UKC.
  • More accurate measurement of the effective depth – Waterways appear to be navigable by ships with larger draft, which is more efficient.


  • Categorization and determination of mud consistency – What are the characteristics of various consistencies of mud and which mud with which consistency could be conditioned?
  • Sailing behaviour – What effects does mud have on the ship? And vice versa: what effects does the ship have on the mud?
  • Monitoring – How to map the mud’s characteristics for the entire port of Rotterdam and then monitor the data?
  • Standardising- Recognition by PIANC and other organizations of the new measurement methods for determining the effective depth of waterways and ports.


  • Cost savings – Decrease of dredging leads to a reduction in dredging costs. 10-20% less dredging saves Rotterdam 1 million euros a year. This provides many opportunities, particulary the areas around the Beer Canal and Caland Canal show great potential.
  • Less hindrance – Less dredging means a reduction in hindrance to ships, which is beneficial to shipping companies and other companies operating in the area.
  • Environment – Less dredging has a positive impact on biodiversity in the port area.
  • Increased load – While continuing dredging at the same rate, ships with larger draft can navigate the same waterways, thus making heavier loading of ships possible. This creates major cost advantages for the shipping companies.


Port of Rotterdam Authority, SmartPort
Knowledge partner: TU Delft

Navigation through fluid mud

“If fluid mud layers can safely and reliably be used in the nautical access policy of ports, a number of sustainable and cost-effective benefits for the dredging process can be reached.”

Arie Noordijk

Manager Ports & Fairways, Port of Rotterdam

Direct contact

More information

Contact our project developer Dirk Koppenol for more information about these and other projects and how you can be part of the SmartPort Community.

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