Alex Kirichek
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98 records found
1
Conference paper
(2027)
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Lisette Võlu, Nadia Pourmohammad-Zia, Floor P. Bakker, Alex Kirichek, Mark van Koningsveld
This paper presents a framework for delineating port nautical infrastructure areas and analysing their usage patterns based on AIS data. Using heuristics, DBSCAN and K-means clustering, three key functional areas are identified (berths, anchorages, and tug-assisted turning areas), and relevant time-based indicators based on area geometries and vessel trajectory sequences are derived. The presented method, though simple and open to further development, can give detailed and comparable insights into port performance and support more effective port planning, traffic management, and operational decision-making.
...
This paper presents a framework for delineating port nautical infrastructure areas and analysing their usage patterns based on AIS data. Using heuristics, DBSCAN and K-means clustering, three key functional areas are identified (berths, anchorages, and tug-assisted turning areas), and relevant time-based indicators based on area geometries and vessel trajectory sequences are derived. The presented method, though simple and open to further development, can give detailed and comparable insights into port performance and support more effective port planning, traffic management, and operational decision-making.
Purpose: Ports worldwide apply different criteria to define navigability, commonly based on density thresholds, yield stress limits, or a combination of both. These criteria are port specific. In the present article, the characterization of the fluid mud found in the Port of Felixstowe (UK) is provided in view of the implementation of a nautical bottom approach. Methods: One-meter sediment cores were collected in the Port of Felixstowe using a Frahmlot sampler and sub-sampled into fluid mud, pre-consolidated, and consolidated layers. Yield stress, bulk density, particle size distribution and organic matter content were measured on the collected samples and compared with data from other ports. The yield stresses as measured in the laboratory were compared with in-situ yield stress measurements in the port. Results: The laboratory analysis shows limited spatial variation of mud in the Port of Felixstowe, while revealing differences in the yield stress-density relation when compared with mud from other ports. The data are also compared with data previously acquired in the Port of Felixstowe. The differences found are attributed to an improper estimation of density measured by the RheoTune. Conclusion: This study focuses on the characterization of the mud from the Port of Felixstowe. It was found that the mud has a yield stress that is lower, for a given density, than other ports. The yield stresses measured in situ using a RheoTune are in agreement with the Bingham yield stresses as measured in the laboratory, while the densities found using the RheoTune are underestimated relative to the laboratory values. The different types of yield stresses, obtained using different rheological protocols, are related to each other, enabling the comparison between in-situ monitoring and laboratory measurements.
...
Purpose: Ports worldwide apply different criteria to define navigability, commonly based on density thresholds, yield stress limits, or a combination of both. These criteria are port specific. In the present article, the characterization of the fluid mud found in the Port of Felixstowe (UK) is provided in view of the implementation of a nautical bottom approach. Methods: One-meter sediment cores were collected in the Port of Felixstowe using a Frahmlot sampler and sub-sampled into fluid mud, pre-consolidated, and consolidated layers. Yield stress, bulk density, particle size distribution and organic matter content were measured on the collected samples and compared with data from other ports. The yield stresses as measured in the laboratory were compared with in-situ yield stress measurements in the port. Results: The laboratory analysis shows limited spatial variation of mud in the Port of Felixstowe, while revealing differences in the yield stress-density relation when compared with mud from other ports. The data are also compared with data previously acquired in the Port of Felixstowe. The differences found are attributed to an improper estimation of density measured by the RheoTune. Conclusion: This study focuses on the characterization of the mud from the Port of Felixstowe. It was found that the mud has a yield stress that is lower, for a given density, than other ports. The yield stresses measured in situ using a RheoTune are in agreement with the Bingham yield stresses as measured in the laboratory, while the densities found using the RheoTune are underestimated relative to the laboratory values. The different types of yield stresses, obtained using different rheological protocols, are related to each other, enabling the comparison between in-situ monitoring and laboratory measurements.
Conference paper
(2026)
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Maryam Pourbeirami Hir, Floor P. Bakker, Alex Kirichek, Fedor Baart, Mark van Koningsveld
Decarbonisation of inland waterway transport requires reliable estimates of propulsion energy use to support the design of zero-emission bunkering infrastructure. Existing approaches rely on averaged or static representations of energy demand, which fail to capture how vessel operations and waterway conditions interact along a corridor. As a result, peak energy requirements and their spatial concentration are systematically underestimated, leading to suboptimal infrastructure planning.
To address this, the study reconstructs vessel movements along the Rotterdam-Basel corridor using empirical trip data and observed hydrodynamic conditions for 2024. A discrete-event simulation is used to represent vessel operations, and battery-electric and hydrogen propulsion systems are evaluated under identical traffic and environmental conditions.
The results show that energy demand is a state-dependent outcome that varies along the corridor rather than a fixed vessel characteristic. Hydrodynamic properties, in particular current velocity, create a spatially heterogeneous demand pattern in which distinct waterway segments consistently concentrate energy use. Under adverse current velocities, these segments exhibit non-linear increases in propulsion requirements and define the upper bounds of corridor energy demand.
These findings show that average-based approaches fail to capture corridor-level properties and underestimate the infrastructure required to ensure operational feasibility. Corridor performance is governed by recurrent high-demand segments rather than mean energy use, suggesting that bunkering infrastructure planning should account for these recurrent high-demand locations rather than rely only on uniform spacing along the corridor. ...
To address this, the study reconstructs vessel movements along the Rotterdam-Basel corridor using empirical trip data and observed hydrodynamic conditions for 2024. A discrete-event simulation is used to represent vessel operations, and battery-electric and hydrogen propulsion systems are evaluated under identical traffic and environmental conditions.
The results show that energy demand is a state-dependent outcome that varies along the corridor rather than a fixed vessel characteristic. Hydrodynamic properties, in particular current velocity, create a spatially heterogeneous demand pattern in which distinct waterway segments consistently concentrate energy use. Under adverse current velocities, these segments exhibit non-linear increases in propulsion requirements and define the upper bounds of corridor energy demand.
These findings show that average-based approaches fail to capture corridor-level properties and underestimate the infrastructure required to ensure operational feasibility. Corridor performance is governed by recurrent high-demand segments rather than mean energy use, suggesting that bunkering infrastructure planning should account for these recurrent high-demand locations rather than rely only on uniform spacing along the corridor. ...
Decarbonisation of inland waterway transport requires reliable estimates of propulsion energy use to support the design of zero-emission bunkering infrastructure. Existing approaches rely on averaged or static representations of energy demand, which fail to capture how vessel operations and waterway conditions interact along a corridor. As a result, peak energy requirements and their spatial concentration are systematically underestimated, leading to suboptimal infrastructure planning.
To address this, the study reconstructs vessel movements along the Rotterdam-Basel corridor using empirical trip data and observed hydrodynamic conditions for 2024. A discrete-event simulation is used to represent vessel operations, and battery-electric and hydrogen propulsion systems are evaluated under identical traffic and environmental conditions.
The results show that energy demand is a state-dependent outcome that varies along the corridor rather than a fixed vessel characteristic. Hydrodynamic properties, in particular current velocity, create a spatially heterogeneous demand pattern in which distinct waterway segments consistently concentrate energy use. Under adverse current velocities, these segments exhibit non-linear increases in propulsion requirements and define the upper bounds of corridor energy demand.
These findings show that average-based approaches fail to capture corridor-level properties and underestimate the infrastructure required to ensure operational feasibility. Corridor performance is governed by recurrent high-demand segments rather than mean energy use, suggesting that bunkering infrastructure planning should account for these recurrent high-demand locations rather than rely only on uniform spacing along the corridor.
To address this, the study reconstructs vessel movements along the Rotterdam-Basel corridor using empirical trip data and observed hydrodynamic conditions for 2024. A discrete-event simulation is used to represent vessel operations, and battery-electric and hydrogen propulsion systems are evaluated under identical traffic and environmental conditions.
The results show that energy demand is a state-dependent outcome that varies along the corridor rather than a fixed vessel characteristic. Hydrodynamic properties, in particular current velocity, create a spatially heterogeneous demand pattern in which distinct waterway segments consistently concentrate energy use. Under adverse current velocities, these segments exhibit non-linear increases in propulsion requirements and define the upper bounds of corridor energy demand.
These findings show that average-based approaches fail to capture corridor-level properties and underestimate the infrastructure required to ensure operational feasibility. Corridor performance is governed by recurrent high-demand segments rather than mean energy use, suggesting that bunkering infrastructure planning should account for these recurrent high-demand locations rather than rely only on uniform spacing along the corridor.
Digital twins for zero-emission inland waterway transport
Developing digital twins for zero-emission and climate-resilient inland waterway transport
Journal article
(2026)
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Alex Kirichek, Fedor Baart, Nadia Pourmohammad-Zia, Dhiraj Kumar, Chinmayee Koodly Ravishankara, Maryam Pourbeirami Hir, Mark van Koningsveld
Inland waterway transport (IWT) is one of Europe’s most energy-efficient freight modes, requiring far less energy per tonne-kilometre than road or rail. Yet, it still contributes to greenhouse gas emissions. Under the European Union (EU) commitment to climate neutrality by 2050, transitioning IWT to zero- emission (ZE) operation has become a key but complex systemic challenge. IWT system performance is shaped by fluctuating water levels, which affect navigability, vessel loading capacity, and energy consumption, as well as by infrastructure constraints and an ageing, heterogeneous fleet. Addressing these challenges requires an integrated approach linking multiple systems, domains, and spatial and temporal scales. A digital twin can provide such a framework by integrating logistics, infrastructure constraints, environmental conditions, fleet composition, operational dynamics, and energy systems. This enables stakeholders to assess operational, tactical, and strategic decisions within a consistent digital environment.
Addressing these challenges requires an integrated approach linking multiple systems, domains, and spatial and temporal scales. A digital twin can provide such a framework by integrating logistics, infrastructure constraints, environmental conditions, fleet composition, operational dynamics, and energy systems. This enables stakeholders to assess operational, tactical, and strategic decisions within a consistent digital environment. ...
Addressing these challenges requires an integrated approach linking multiple systems, domains, and spatial and temporal scales. A digital twin can provide such a framework by integrating logistics, infrastructure constraints, environmental conditions, fleet composition, operational dynamics, and energy systems. This enables stakeholders to assess operational, tactical, and strategic decisions within a consistent digital environment. ...
Inland waterway transport (IWT) is one of Europe’s most energy-efficient freight modes, requiring far less energy per tonne-kilometre than road or rail. Yet, it still contributes to greenhouse gas emissions. Under the European Union (EU) commitment to climate neutrality by 2050, transitioning IWT to zero- emission (ZE) operation has become a key but complex systemic challenge. IWT system performance is shaped by fluctuating water levels, which affect navigability, vessel loading capacity, and energy consumption, as well as by infrastructure constraints and an ageing, heterogeneous fleet. Addressing these challenges requires an integrated approach linking multiple systems, domains, and spatial and temporal scales. A digital twin can provide such a framework by integrating logistics, infrastructure constraints, environmental conditions, fleet composition, operational dynamics, and energy systems. This enables stakeholders to assess operational, tactical, and strategic decisions within a consistent digital environment.
Addressing these challenges requires an integrated approach linking multiple systems, domains, and spatial and temporal scales. A digital twin can provide such a framework by integrating logistics, infrastructure constraints, environmental conditions, fleet composition, operational dynamics, and energy systems. This enables stakeholders to assess operational, tactical, and strategic decisions within a consistent digital environment.
Addressing these challenges requires an integrated approach linking multiple systems, domains, and spatial and temporal scales. A digital twin can provide such a framework by integrating logistics, infrastructure constraints, environmental conditions, fleet composition, operational dynamics, and energy systems. This enables stakeholders to assess operational, tactical, and strategic decisions within a consistent digital environment.
Sustainable port maintenance
Dredging equipment selection in time-emission trade-offs
Journal article
(2026)
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Arash Sepehri, Alex Kirichek, Marcel van den Heuvel, Martin de Geus, Mark van Koningsveld
Maintenance dredging in ports and waterways is essential to ensure safe navigation. With increasing regulatory pressure on the maritime sector to reduce exhaust emissions, both dredging contractors and port authorities are seeking effective mitigation strategies. However, accurate emission estimates for maintenance dredging activities are still limited in the literature and often rely on experiential knowledge rather than scientific methodologies. This study suggests a method for estimating emissions and comparing alternative maintenance dredging strategies by quantifying trade-offs between project duration, energy consumption, and emissions. The method integrates vessel characteristics, project specifications, and sediment properties to allow for situation-specific, realistic assessments. A discrete-event simulation is used to evaluate two alternative scenarios, offering insights into the impact of key parameters on vessel selection and overall operational efficiency. The method is demonstrated using a case study of the Port of Ramsgate (UK), where estimated results are compared with real-world data for validation. Finally, the study outlines theoretical and managerial implications and suggests directions for future research.
...
Maintenance dredging in ports and waterways is essential to ensure safe navigation. With increasing regulatory pressure on the maritime sector to reduce exhaust emissions, both dredging contractors and port authorities are seeking effective mitigation strategies. However, accurate emission estimates for maintenance dredging activities are still limited in the literature and often rely on experiential knowledge rather than scientific methodologies. This study suggests a method for estimating emissions and comparing alternative maintenance dredging strategies by quantifying trade-offs between project duration, energy consumption, and emissions. The method integrates vessel characteristics, project specifications, and sediment properties to allow for situation-specific, realistic assessments. A discrete-event simulation is used to evaluate two alternative scenarios, offering insights into the impact of key parameters on vessel selection and overall operational efficiency. The method is demonstrated using a case study of the Port of Ramsgate (UK), where estimated results are compared with real-world data for validation. Finally, the study outlines theoretical and managerial implications and suggests directions for future research.
From linear to circular port maintenance dredging
A case study of beneficial reuse of dredged material for dike reinforcement
Purpose
Maintenance dredging is essential for navigability but often follows linear “extract–dispose” practices that lead to material loss and offshore impacts. This study develops a structured framework to quantify circularity in maintenance dredging and evaluates how sediment reuse can contribute to regenerative port management. The central question is how circularity, through material retention, reuse, and reduced environmental impact, can be measured and compared against conventional offshore disposal strategies.
Methods
A circularity assessment framework was developed by integrating circular economy principles with process-based modeling of dredging operations. The framework combines operational, environmental, and material performance dimensions and applies the Material Re-utilization Score (MRS) and Material Circularity Indicator (MCI) to quantify sediment retention and flow quality. A discrete-event simulation using OpenCLSim was coupled with physics-based power, energy, and emission models to analyze two scenarios at the Port of Delfzijl (the Netherlands): (1) linear offshore disposal with a Trailing Suction Hopper Dredger, and (2) circular reuse through discharge into clay-ripening compartments for dike reinforcement. Event tables were used to structure activities, operational durations, energy use, emissions, and sediment state transformations.
Results
The circular scenario achieved substantial material recovery (MRS = 0.87; MCI = 0.78), whereas offshore disposal resulted in zero circularity. Despite higher establishment costs and longer total project duration due to ripening, the circular scenario required 23% less operational energy and produced fewer emissions, primarily because of shorter sailing distances. Operational dredging time was comparable between scenarios, demonstrating that circularity does not inherently reduce efficiency. The event-table approach revealed explicit trade-offs between logistics, material degradation, energy use, and utility of the final clay product. Overall, transitioning to circular dredging requires upfront investment but yields long-term value through resource retention and reduced dependence on offshore disposal.
Conclusions
This study provides a quantitative framework for assessing circularity in maintenance dredging and demonstrates its practical applicability through a real port case. Circular reuse of dredged sediment offers measurable material and environmental benefits despite increased preparation requirements. The framework enables evidence-based comparison of linear and circular strategies, supporting decision-makers seeking to advance regenerative, resource-efficient, and sustainable port maintenance practices. ...
Maintenance dredging is essential for navigability but often follows linear “extract–dispose” practices that lead to material loss and offshore impacts. This study develops a structured framework to quantify circularity in maintenance dredging and evaluates how sediment reuse can contribute to regenerative port management. The central question is how circularity, through material retention, reuse, and reduced environmental impact, can be measured and compared against conventional offshore disposal strategies.
Methods
A circularity assessment framework was developed by integrating circular economy principles with process-based modeling of dredging operations. The framework combines operational, environmental, and material performance dimensions and applies the Material Re-utilization Score (MRS) and Material Circularity Indicator (MCI) to quantify sediment retention and flow quality. A discrete-event simulation using OpenCLSim was coupled with physics-based power, energy, and emission models to analyze two scenarios at the Port of Delfzijl (the Netherlands): (1) linear offshore disposal with a Trailing Suction Hopper Dredger, and (2) circular reuse through discharge into clay-ripening compartments for dike reinforcement. Event tables were used to structure activities, operational durations, energy use, emissions, and sediment state transformations.
Results
The circular scenario achieved substantial material recovery (MRS = 0.87; MCI = 0.78), whereas offshore disposal resulted in zero circularity. Despite higher establishment costs and longer total project duration due to ripening, the circular scenario required 23% less operational energy and produced fewer emissions, primarily because of shorter sailing distances. Operational dredging time was comparable between scenarios, demonstrating that circularity does not inherently reduce efficiency. The event-table approach revealed explicit trade-offs between logistics, material degradation, energy use, and utility of the final clay product. Overall, transitioning to circular dredging requires upfront investment but yields long-term value through resource retention and reduced dependence on offshore disposal.
Conclusions
This study provides a quantitative framework for assessing circularity in maintenance dredging and demonstrates its practical applicability through a real port case. Circular reuse of dredged sediment offers measurable material and environmental benefits despite increased preparation requirements. The framework enables evidence-based comparison of linear and circular strategies, supporting decision-makers seeking to advance regenerative, resource-efficient, and sustainable port maintenance practices. ...
Purpose
Maintenance dredging is essential for navigability but often follows linear “extract–dispose” practices that lead to material loss and offshore impacts. This study develops a structured framework to quantify circularity in maintenance dredging and evaluates how sediment reuse can contribute to regenerative port management. The central question is how circularity, through material retention, reuse, and reduced environmental impact, can be measured and compared against conventional offshore disposal strategies.
Methods
A circularity assessment framework was developed by integrating circular economy principles with process-based modeling of dredging operations. The framework combines operational, environmental, and material performance dimensions and applies the Material Re-utilization Score (MRS) and Material Circularity Indicator (MCI) to quantify sediment retention and flow quality. A discrete-event simulation using OpenCLSim was coupled with physics-based power, energy, and emission models to analyze two scenarios at the Port of Delfzijl (the Netherlands): (1) linear offshore disposal with a Trailing Suction Hopper Dredger, and (2) circular reuse through discharge into clay-ripening compartments for dike reinforcement. Event tables were used to structure activities, operational durations, energy use, emissions, and sediment state transformations.
Results
The circular scenario achieved substantial material recovery (MRS = 0.87; MCI = 0.78), whereas offshore disposal resulted in zero circularity. Despite higher establishment costs and longer total project duration due to ripening, the circular scenario required 23% less operational energy and produced fewer emissions, primarily because of shorter sailing distances. Operational dredging time was comparable between scenarios, demonstrating that circularity does not inherently reduce efficiency. The event-table approach revealed explicit trade-offs between logistics, material degradation, energy use, and utility of the final clay product. Overall, transitioning to circular dredging requires upfront investment but yields long-term value through resource retention and reduced dependence on offshore disposal.
Conclusions
This study provides a quantitative framework for assessing circularity in maintenance dredging and demonstrates its practical applicability through a real port case. Circular reuse of dredged sediment offers measurable material and environmental benefits despite increased preparation requirements. The framework enables evidence-based comparison of linear and circular strategies, supporting decision-makers seeking to advance regenerative, resource-efficient, and sustainable port maintenance practices.
Maintenance dredging is essential for navigability but often follows linear “extract–dispose” practices that lead to material loss and offshore impacts. This study develops a structured framework to quantify circularity in maintenance dredging and evaluates how sediment reuse can contribute to regenerative port management. The central question is how circularity, through material retention, reuse, and reduced environmental impact, can be measured and compared against conventional offshore disposal strategies.
Methods
A circularity assessment framework was developed by integrating circular economy principles with process-based modeling of dredging operations. The framework combines operational, environmental, and material performance dimensions and applies the Material Re-utilization Score (MRS) and Material Circularity Indicator (MCI) to quantify sediment retention and flow quality. A discrete-event simulation using OpenCLSim was coupled with physics-based power, energy, and emission models to analyze two scenarios at the Port of Delfzijl (the Netherlands): (1) linear offshore disposal with a Trailing Suction Hopper Dredger, and (2) circular reuse through discharge into clay-ripening compartments for dike reinforcement. Event tables were used to structure activities, operational durations, energy use, emissions, and sediment state transformations.
Results
The circular scenario achieved substantial material recovery (MRS = 0.87; MCI = 0.78), whereas offshore disposal resulted in zero circularity. Despite higher establishment costs and longer total project duration due to ripening, the circular scenario required 23% less operational energy and produced fewer emissions, primarily because of shorter sailing distances. Operational dredging time was comparable between scenarios, demonstrating that circularity does not inherently reduce efficiency. The event-table approach revealed explicit trade-offs between logistics, material degradation, energy use, and utility of the final clay product. Overall, transitioning to circular dredging requires upfront investment but yields long-term value through resource retention and reduced dependence on offshore disposal.
Conclusions
This study provides a quantitative framework for assessing circularity in maintenance dredging and demonstrates its practical applicability through a real port case. Circular reuse of dredged sediment offers measurable material and environmental benefits despite increased preparation requirements. The framework enables evidence-based comparison of linear and circular strategies, supporting decision-makers seeking to advance regenerative, resource-efficient, and sustainable port maintenance practices.
Dewatering of dredged sediment often relies on chemicals and heavy machinery, which increase fossil fuel use and emissions [1]. Traditional sediment dewatering methods only worsen the financial and environmental burdens associated with sediment management. When the slurry eventually dries at dewatering fields, it is perceived that the biological quality of the resulting sediment does not meet the standards of healthy soil, meaning it is rarely reused. It is also important to note that none of the existing commercial dewatering methods improve the environmental quality of the final product; they only address its physical properties.
Over the past decade, more nature friendly innovative methods have been developed [2]. These methods use only endemic fauna and flora to significantly accelerate the dewatering process for various types of slurry. Additionally, the treated final product resembles closely biological properties of soil. Soil is a valuable resource, which would otherwise need to source it from the commercial soil market, a process that is both expensive and environmentally harmful due to operations-related emissions. ...
Over the past decade, more nature friendly innovative methods have been developed [2]. These methods use only endemic fauna and flora to significantly accelerate the dewatering process for various types of slurry. Additionally, the treated final product resembles closely biological properties of soil. Soil is a valuable resource, which would otherwise need to source it from the commercial soil market, a process that is both expensive and environmentally harmful due to operations-related emissions. ...
Dewatering of dredged sediment often relies on chemicals and heavy machinery, which increase fossil fuel use and emissions [1]. Traditional sediment dewatering methods only worsen the financial and environmental burdens associated with sediment management. When the slurry eventually dries at dewatering fields, it is perceived that the biological quality of the resulting sediment does not meet the standards of healthy soil, meaning it is rarely reused. It is also important to note that none of the existing commercial dewatering methods improve the environmental quality of the final product; they only address its physical properties.
Over the past decade, more nature friendly innovative methods have been developed [2]. These methods use only endemic fauna and flora to significantly accelerate the dewatering process for various types of slurry. Additionally, the treated final product resembles closely biological properties of soil. Soil is a valuable resource, which would otherwise need to source it from the commercial soil market, a process that is both expensive and environmentally harmful due to operations-related emissions.
Over the past decade, more nature friendly innovative methods have been developed [2]. These methods use only endemic fauna and flora to significantly accelerate the dewatering process for various types of slurry. Additionally, the treated final product resembles closely biological properties of soil. Soil is a valuable resource, which would otherwise need to source it from the commercial soil market, a process that is both expensive and environmentally harmful due to operations-related emissions.
Floc size distribution and settling velocities are crucial parameters for characterising cohesive sediments, as they influence how these sediments behave in various environmental settings. The accurate measurement of these properties is essential, with different methods available depending on the scope of the study. For long-term monitoring, in situ techniques based on laser diffraction are commonly used, while video microscopy techniques are preferred for shorter studies due to their ability to provide detailed information on individual particles. This study compares two high-magnification digital video camera setups, LabSFLOC-2 and FLOCCAM, to investigate the impact of particle concentration on settling velocity in flocculated sediments. Flocculated clay was introduced into settling columns, where both the size and settling velocities of the flocs were measured. The results obtained from both setups are in line with each other, even though the FLOCCAM was slightly more efficient at capturing images of small particles (of size less than 50 microns) and LabsFLOC-2 was better at detecting large size fraction particles (having a low contrast due to the presence of organic matter). Floc size and settling velocity measurements from both setups however exhibit mostly similar trends as a function of clay concentration and the same order of magnitudes for the recorded settling velocities.
...
Floc size distribution and settling velocities are crucial parameters for characterising cohesive sediments, as they influence how these sediments behave in various environmental settings. The accurate measurement of these properties is essential, with different methods available depending on the scope of the study. For long-term monitoring, in situ techniques based on laser diffraction are commonly used, while video microscopy techniques are preferred for shorter studies due to their ability to provide detailed information on individual particles. This study compares two high-magnification digital video camera setups, LabSFLOC-2 and FLOCCAM, to investigate the impact of particle concentration on settling velocity in flocculated sediments. Flocculated clay was introduced into settling columns, where both the size and settling velocities of the flocs were measured. The results obtained from both setups are in line with each other, even though the FLOCCAM was slightly more efficient at capturing images of small particles (of size less than 50 microns) and LabsFLOC-2 was better at detecting large size fraction particles (having a low contrast due to the presence of organic matter). Floc size and settling velocity measurements from both setups however exhibit mostly similar trends as a function of clay concentration and the same order of magnitudes for the recorded settling velocities.
The UK’s largest container port at Felixstowe, faces significant sedimentation challenges, with approximately 2.4 million m³ of sediment requiring management annually [1]. To optimize maintenance strategies and enhance navigability, Harwich Haven Authority is exploring the implementation of PIANC’s nautical bottom concept [2], which relies on understanding the rheological and settling behaviour of muddy bed in the port.
This study examines the shear strength (yield stress) evolution of soft mud layers by investigating their physical properties (e.g., density, organic matter, salinity, etc.), rheological behaviour such as yield stresses and thixotropy, and how these properties develop over time. By linking these temporal changes due to sediment settling and consolidation processes, the research aims to identify critical thresholds for navigability. ...
This study examines the shear strength (yield stress) evolution of soft mud layers by investigating their physical properties (e.g., density, organic matter, salinity, etc.), rheological behaviour such as yield stresses and thixotropy, and how these properties develop over time. By linking these temporal changes due to sediment settling and consolidation processes, the research aims to identify critical thresholds for navigability. ...
The UK’s largest container port at Felixstowe, faces significant sedimentation challenges, with approximately 2.4 million m³ of sediment requiring management annually [1]. To optimize maintenance strategies and enhance navigability, Harwich Haven Authority is exploring the implementation of PIANC’s nautical bottom concept [2], which relies on understanding the rheological and settling behaviour of muddy bed in the port.
This study examines the shear strength (yield stress) evolution of soft mud layers by investigating their physical properties (e.g., density, organic matter, salinity, etc.), rheological behaviour such as yield stresses and thixotropy, and how these properties develop over time. By linking these temporal changes due to sediment settling and consolidation processes, the research aims to identify critical thresholds for navigability.
This study examines the shear strength (yield stress) evolution of soft mud layers by investigating their physical properties (e.g., density, organic matter, salinity, etc.), rheological behaviour such as yield stresses and thixotropy, and how these properties develop over time. By linking these temporal changes due to sediment settling and consolidation processes, the research aims to identify critical thresholds for navigability.
The concept of circularity is used as an alternative to linear flow materials in order to protect the environment from potential damage. To determine to what extent a sediment management project contributes to circularity practices, it is necessary to quantify how much of the dredged material is maintained within the system. Hence, defining boundaries for the system and circularity indicators for dredged material plays a vital role in measuring the circularity level of a certain project [1]. This study concentrates on defining circularity indicators for sediment management projects when a certain amount of material is diminished during the pre-processing stage. Besides, the perspectives of different stakeholders (e.g. port authorities, and dredging contractors) influence the selection of strategies for circular maintenance dredging [2].
...
The concept of circularity is used as an alternative to linear flow materials in order to protect the environment from potential damage. To determine to what extent a sediment management project contributes to circularity practices, it is necessary to quantify how much of the dredged material is maintained within the system. Hence, defining boundaries for the system and circularity indicators for dredged material plays a vital role in measuring the circularity level of a certain project [1]. This study concentrates on defining circularity indicators for sediment management projects when a certain amount of material is diminished during the pre-processing stage. Besides, the perspectives of different stakeholders (e.g. port authorities, and dredging contractors) influence the selection of strategies for circular maintenance dredging [2].
Mud is a fine-grained cohesive material which contains mineral particles (predominantly clay and silt), organic (and inorganic) matter, and water. Understanding mud’s rheological and settling behaviour is critical for sustainable sediment management in ports [1, 2]. A systematic analysis of the effect of clay minerology on the rheological and settling behaviour of mud has been conducted previously [3, 4]. In contrast, literature on the impact of organic matter on physical properties of sediment is scarce. Our previous work [5] demonstrated the impact of microbial inactivation via gamma radiation, revealing a significant increase in settling rates. Current research incorporates chemical sterilization (NaN3) and organic matter removal (NaOCl), to systematically differentiate between effects of microbial activity and effects of organic matter on the physical properties of fluid mud (FM).
...
Mud is a fine-grained cohesive material which contains mineral particles (predominantly clay and silt), organic (and inorganic) matter, and water. Understanding mud’s rheological and settling behaviour is critical for sustainable sediment management in ports [1, 2]. A systematic analysis of the effect of clay minerology on the rheological and settling behaviour of mud has been conducted previously [3, 4]. In contrast, literature on the impact of organic matter on physical properties of sediment is scarce. Our previous work [5] demonstrated the impact of microbial inactivation via gamma radiation, revealing a significant increase in settling rates. Current research incorporates chemical sterilization (NaN3) and organic matter removal (NaOCl), to systematically differentiate between effects of microbial activity and effects of organic matter on the physical properties of fluid mud (FM).
Conference paper
(2025)
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Maryam Pourbeirami Hir, Alex Kirichek, Nadia Pourmohammadzia, Mark van Koningsveld
Inland waterway transport (IWT) is increasingly recognized as a cleaner, more efficient alternative to road transport for freight movement. However, the successful adoption of zero-emission fuelsparticularly hydrogen and battery power-depends on the strategic location and capacity of bunkering and charging stations. This extended abstract presents a multi-stage framework that combines simulation and mixed-integer optimization to identify where and how these stations should be deployed. First, a simulation model estimates the fuel consumption of vessels under varied waterway conditions, vessel dimensions, and hydrodynamic influences. Next, an optimization module, modeled within the supply chain, aims to minimize capital and operating expenses while ensuring sufficient fuel availability. Strategically placing multi-fuel stations in high-demand locations reduces infrastructure redundancy and ensures flexible operations. This study underlines the critical role of well-planned bunkering infrastructures and highlights the potential for future expansions in zeroemission vessel networks.
...
Inland waterway transport (IWT) is increasingly recognized as a cleaner, more efficient alternative to road transport for freight movement. However, the successful adoption of zero-emission fuelsparticularly hydrogen and battery power-depends on the strategic location and capacity of bunkering and charging stations. This extended abstract presents a multi-stage framework that combines simulation and mixed-integer optimization to identify where and how these stations should be deployed. First, a simulation model estimates the fuel consumption of vessels under varied waterway conditions, vessel dimensions, and hydrodynamic influences. Next, an optimization module, modeled within the supply chain, aims to minimize capital and operating expenses while ensuring sufficient fuel availability. Strategically placing multi-fuel stations in high-demand locations reduces infrastructure redundancy and ensures flexible operations. This study underlines the critical role of well-planned bunkering infrastructures and highlights the potential for future expansions in zeroemission vessel networks.
Project Nautical Depth
New Approaches in safe berthing and sailing through fluid mud at Hamburg-Port
Conference paper
(2024)
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N. Ohle, U. Schmekel, C. Bottner, I. Shevchuk, M. Abdel-Maksoud, A. Kirichek
For future strategies in water depth maintenance in the Port of Hamburg, determining the navigability limit (i.e., the safe nautical depth) is of major importance. For this purpose, the project Nautical Depth was set up at the Hamburg Port Authority. The aim of the project is to measure a safe nautical depth under various boundary conditions and to identify limits for a safe passage in port areas with fluid mud. Among other things, the project is conducted in close collaboration with the Port of Antwerp Bruges, the Port of Rotterdam, and TU Delft within the research platform MUDNET (www.tudelft.nl/mudnet).
To gain the necessary acceptance for a reassessment of the nautical depth, it is important to determine the rheological properties of the sediment in-situ. Several existing survey devices for monitoring nautical relevant rheological sediment properties have been tested. However, these devices cannot be used for spatial determination of rheological properties as they only provide cross-sectional measurements and depth profiles. Therefore, new evaluation algorithms were developed to correlate echo sounding data with in-situ rheological properties to ensure spatial coverage of a safe nautical depth.
As a first step, hydrographic surveys and sampling campaigns were carried out to provide system knowledge of the water column and the riverbed. Basic scientific research on the rheological behaviour of the fluid mud was also carried out. In a second step, the safe conditions for adapting the fluid mud layers at the berths for the nautical bottom concept were investigated and new nautical depth approaches were introduced at different locations in the Port of Hamburg. The next step was to analyse the effect of the fluid mud on the manoeuvrability of the ships. To this end, existing Computational Fluid Dynamics (CFD) models were extended to determine the non-linear effects and forces of non-Newton fluids on ship hull, rudder, and propeller efficiency. The results of the CFD model have been and are being validated with hydraulic model tests (scale 1:60) and in-situ measurements in the Port of Hamburg. In a final step, the results of the CFD model will be used to adapt the software of existing ship handling simulators. These simulations will be used to define the safe boundary conditions and limits for a new nautical depth for vessels to navigate through the fluid mud. ...
To gain the necessary acceptance for a reassessment of the nautical depth, it is important to determine the rheological properties of the sediment in-situ. Several existing survey devices for monitoring nautical relevant rheological sediment properties have been tested. However, these devices cannot be used for spatial determination of rheological properties as they only provide cross-sectional measurements and depth profiles. Therefore, new evaluation algorithms were developed to correlate echo sounding data with in-situ rheological properties to ensure spatial coverage of a safe nautical depth.
As a first step, hydrographic surveys and sampling campaigns were carried out to provide system knowledge of the water column and the riverbed. Basic scientific research on the rheological behaviour of the fluid mud was also carried out. In a second step, the safe conditions for adapting the fluid mud layers at the berths for the nautical bottom concept were investigated and new nautical depth approaches were introduced at different locations in the Port of Hamburg. The next step was to analyse the effect of the fluid mud on the manoeuvrability of the ships. To this end, existing Computational Fluid Dynamics (CFD) models were extended to determine the non-linear effects and forces of non-Newton fluids on ship hull, rudder, and propeller efficiency. The results of the CFD model have been and are being validated with hydraulic model tests (scale 1:60) and in-situ measurements in the Port of Hamburg. In a final step, the results of the CFD model will be used to adapt the software of existing ship handling simulators. These simulations will be used to define the safe boundary conditions and limits for a new nautical depth for vessels to navigate through the fluid mud. ...
For future strategies in water depth maintenance in the Port of Hamburg, determining the navigability limit (i.e., the safe nautical depth) is of major importance. For this purpose, the project Nautical Depth was set up at the Hamburg Port Authority. The aim of the project is to measure a safe nautical depth under various boundary conditions and to identify limits for a safe passage in port areas with fluid mud. Among other things, the project is conducted in close collaboration with the Port of Antwerp Bruges, the Port of Rotterdam, and TU Delft within the research platform MUDNET (www.tudelft.nl/mudnet).
To gain the necessary acceptance for a reassessment of the nautical depth, it is important to determine the rheological properties of the sediment in-situ. Several existing survey devices for monitoring nautical relevant rheological sediment properties have been tested. However, these devices cannot be used for spatial determination of rheological properties as they only provide cross-sectional measurements and depth profiles. Therefore, new evaluation algorithms were developed to correlate echo sounding data with in-situ rheological properties to ensure spatial coverage of a safe nautical depth.
As a first step, hydrographic surveys and sampling campaigns were carried out to provide system knowledge of the water column and the riverbed. Basic scientific research on the rheological behaviour of the fluid mud was also carried out. In a second step, the safe conditions for adapting the fluid mud layers at the berths for the nautical bottom concept were investigated and new nautical depth approaches were introduced at different locations in the Port of Hamburg. The next step was to analyse the effect of the fluid mud on the manoeuvrability of the ships. To this end, existing Computational Fluid Dynamics (CFD) models were extended to determine the non-linear effects and forces of non-Newton fluids on ship hull, rudder, and propeller efficiency. The results of the CFD model have been and are being validated with hydraulic model tests (scale 1:60) and in-situ measurements in the Port of Hamburg. In a final step, the results of the CFD model will be used to adapt the software of existing ship handling simulators. These simulations will be used to define the safe boundary conditions and limits for a new nautical depth for vessels to navigate through the fluid mud.
To gain the necessary acceptance for a reassessment of the nautical depth, it is important to determine the rheological properties of the sediment in-situ. Several existing survey devices for monitoring nautical relevant rheological sediment properties have been tested. However, these devices cannot be used for spatial determination of rheological properties as they only provide cross-sectional measurements and depth profiles. Therefore, new evaluation algorithms were developed to correlate echo sounding data with in-situ rheological properties to ensure spatial coverage of a safe nautical depth.
As a first step, hydrographic surveys and sampling campaigns were carried out to provide system knowledge of the water column and the riverbed. Basic scientific research on the rheological behaviour of the fluid mud was also carried out. In a second step, the safe conditions for adapting the fluid mud layers at the berths for the nautical bottom concept were investigated and new nautical depth approaches were introduced at different locations in the Port of Hamburg. The next step was to analyse the effect of the fluid mud on the manoeuvrability of the ships. To this end, existing Computational Fluid Dynamics (CFD) models were extended to determine the non-linear effects and forces of non-Newton fluids on ship hull, rudder, and propeller efficiency. The results of the CFD model have been and are being validated with hydraulic model tests (scale 1:60) and in-situ measurements in the Port of Hamburg. In a final step, the results of the CFD model will be used to adapt the software of existing ship handling simulators. These simulations will be used to define the safe boundary conditions and limits for a new nautical depth for vessels to navigate through the fluid mud.
Safe navigation in ports and waterways subjected to siltation requires nautical depth monitoring. For this purpose, surveying vessels equipped with a zero-offset echo sounder and intrusive point measurements are frequently used. Because these measurements depend on the availability of a surveying vessel and require access to quay walls, such as at the container terminals in seaports, the temporal resolution is limited. Especially at these locations, a high temporal resolution monitoring system could allow for a higher occupancy rate. We propose to use Distributed Acoustic Sensing to monitor the nautical depth using fiber-optical cables. We install five horizontal fibers at different heights between two points and continuously record along the complete installation. Analysing the continuous recordings, we show that horizontal fibers can be used to monitor the water-mud interface depth with a vertical resolution around six mm. Multiple passive sources, like vessel movements and water currents, are used to estimate the water-mud interface.
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Safe navigation in ports and waterways subjected to siltation requires nautical depth monitoring. For this purpose, surveying vessels equipped with a zero-offset echo sounder and intrusive point measurements are frequently used. Because these measurements depend on the availability of a surveying vessel and require access to quay walls, such as at the container terminals in seaports, the temporal resolution is limited. Especially at these locations, a high temporal resolution monitoring system could allow for a higher occupancy rate. We propose to use Distributed Acoustic Sensing to monitor the nautical depth using fiber-optical cables. We install five horizontal fibers at different heights between two points and continuously record along the complete installation. Analysing the continuous recordings, we show that horizontal fibers can be used to monitor the water-mud interface depth with a vertical resolution around six mm. Multiple passive sources, like vessel movements and water currents, are used to estimate the water-mud interface.
Book chapter
(2024)
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R.L.J. Helmons, S.M.S. Alhaddad, C. Chassagne, M.F.A.I. Elerian, G.H. Keetels, Alex Kirichek, Laurenz Thomsen
The chapter gives an overview of the sediment dispersion generated by the mining process. Within the field of dredging engineering, ample experience is available regarding equipment, turbidity generated by equipment, and sediment transport processes. High up the environmental impact mitigation hierarchy are avoidance and minimization. That is where engineering can provide (part of) the solution. It is our aim to predict and consider how we can improve the mining process and equipment. Within this context, our focus is on those processes that are likely to take place close to the seabed. On the one hand, our work focuses on the prediction and reduction of the amount of sediment that might get suspended. On the other hand, considering the conditions under which the suspended sediment might be released in the most optimal way to reduce dispersion, we have performed and analysed small-scale and full-scale laboratory experiments of a hydraulic collector design and various dynamic sedimentation experiments.
...
The chapter gives an overview of the sediment dispersion generated by the mining process. Within the field of dredging engineering, ample experience is available regarding equipment, turbidity generated by equipment, and sediment transport processes. High up the environmental impact mitigation hierarchy are avoidance and minimization. That is where engineering can provide (part of) the solution. It is our aim to predict and consider how we can improve the mining process and equipment. Within this context, our focus is on those processes that are likely to take place close to the seabed. On the one hand, our work focuses on the prediction and reduction of the amount of sediment that might get suspended. On the other hand, considering the conditions under which the suspended sediment might be released in the most optimal way to reduce dispersion, we have performed and analysed small-scale and full-scale laboratory experiments of a hydraulic collector design and various dynamic sedimentation experiments.
Agitation dredging of silt and fine sand with Water Injection Dredging, Tiamat and Underwater Plough
A case study in the Port of Rotterdam
Purpose
Agitation dredging has gained popularity as an environmentally friendly and cost-effective method for port maintenance. One of the advantages of agitation dredging is the ability to transport sediments out of the port area using natural currents. The effect of the different agitation methods on sediment and water properties has rarely been investigated in a single pilot project. This research aims to study the effects of agitation methods in silt and sand-dominated areas that are frequently maintained.
Methods
The effects of water injection dredging, (WID) underwater ploughing (UWP) and Tiamat on sediment properties are investigated in the Port of Rotterdam. In-situ measurements and laboratory measurements are carried out to determine changes in the bed level, the particle size distribution of the bed, the turbidity in the water column and the dispersion distance of the sediment plume due to agitation dredging.
Results
The results of the in-situ monitoring of the agitation pilots allow a comparison of the changes in sediment and water properties before, during and after agitation dredging. The production, advantages and limitations of the tested agitation dredging methods are discussed.
Conclusion
The in-situ measurements show that WID, Tiamat and UWP can be successfully used for the agitation of sediments and their removal from the silt and sand-dominated areas. The production of the tested agitation methods is higher for silty than sandy sediments. In general, the selection of the agitation equipment can be made based on environmental regulations, sediment properties and hydrodynamic conditions. ...
Agitation dredging has gained popularity as an environmentally friendly and cost-effective method for port maintenance. One of the advantages of agitation dredging is the ability to transport sediments out of the port area using natural currents. The effect of the different agitation methods on sediment and water properties has rarely been investigated in a single pilot project. This research aims to study the effects of agitation methods in silt and sand-dominated areas that are frequently maintained.
Methods
The effects of water injection dredging, (WID) underwater ploughing (UWP) and Tiamat on sediment properties are investigated in the Port of Rotterdam. In-situ measurements and laboratory measurements are carried out to determine changes in the bed level, the particle size distribution of the bed, the turbidity in the water column and the dispersion distance of the sediment plume due to agitation dredging.
Results
The results of the in-situ monitoring of the agitation pilots allow a comparison of the changes in sediment and water properties before, during and after agitation dredging. The production, advantages and limitations of the tested agitation dredging methods are discussed.
Conclusion
The in-situ measurements show that WID, Tiamat and UWP can be successfully used for the agitation of sediments and their removal from the silt and sand-dominated areas. The production of the tested agitation methods is higher for silty than sandy sediments. In general, the selection of the agitation equipment can be made based on environmental regulations, sediment properties and hydrodynamic conditions. ...
Purpose
Agitation dredging has gained popularity as an environmentally friendly and cost-effective method for port maintenance. One of the advantages of agitation dredging is the ability to transport sediments out of the port area using natural currents. The effect of the different agitation methods on sediment and water properties has rarely been investigated in a single pilot project. This research aims to study the effects of agitation methods in silt and sand-dominated areas that are frequently maintained.
Methods
The effects of water injection dredging, (WID) underwater ploughing (UWP) and Tiamat on sediment properties are investigated in the Port of Rotterdam. In-situ measurements and laboratory measurements are carried out to determine changes in the bed level, the particle size distribution of the bed, the turbidity in the water column and the dispersion distance of the sediment plume due to agitation dredging.
Results
The results of the in-situ monitoring of the agitation pilots allow a comparison of the changes in sediment and water properties before, during and after agitation dredging. The production, advantages and limitations of the tested agitation dredging methods are discussed.
Conclusion
The in-situ measurements show that WID, Tiamat and UWP can be successfully used for the agitation of sediments and their removal from the silt and sand-dominated areas. The production of the tested agitation methods is higher for silty than sandy sediments. In general, the selection of the agitation equipment can be made based on environmental regulations, sediment properties and hydrodynamic conditions.
Agitation dredging has gained popularity as an environmentally friendly and cost-effective method for port maintenance. One of the advantages of agitation dredging is the ability to transport sediments out of the port area using natural currents. The effect of the different agitation methods on sediment and water properties has rarely been investigated in a single pilot project. This research aims to study the effects of agitation methods in silt and sand-dominated areas that are frequently maintained.
Methods
The effects of water injection dredging, (WID) underwater ploughing (UWP) and Tiamat on sediment properties are investigated in the Port of Rotterdam. In-situ measurements and laboratory measurements are carried out to determine changes in the bed level, the particle size distribution of the bed, the turbidity in the water column and the dispersion distance of the sediment plume due to agitation dredging.
Results
The results of the in-situ monitoring of the agitation pilots allow a comparison of the changes in sediment and water properties before, during and after agitation dredging. The production, advantages and limitations of the tested agitation dredging methods are discussed.
Conclusion
The in-situ measurements show that WID, Tiamat and UWP can be successfully used for the agitation of sediments and their removal from the silt and sand-dominated areas. The production of the tested agitation methods is higher for silty than sandy sediments. In general, the selection of the agitation equipment can be made based on environmental regulations, sediment properties and hydrodynamic conditions.
Bridging the depth
Lessons learned from deep-sea mining for better predicting turbidity plumes
The insights gained from deep-sea mining (DSM) research regarding sediment dynamics can be utilized to better predict turbidity plumes in shallow marine environments. Small-scale lab experiments can replicate deep-sea conditions effectively, offering an ideal model system to study turbidity currents, given the reduced hydrodynamics and low biota present in the deep sea. DSM operations involve the deployment of a Polymetallic Nodule Mining Tool (PNMT) that collects ore and discharges excess water and sediments. Organic matter, bound to mineral clay as floes, is a key driver of sediment transport in the deep sea. Understanding the dispersal and settling patterns of sediments, and the likelihood of flocculation occurring in DSM activities, can be generalized and applied to turbid flows in shallow water areas. Laboratory experiments demonstrate that the interaction between organic matter, mineral clay, and floes within turbidity currents, results in the reduction of their dispersion. Alongside this, factors like shear rate and sediment concentration significantly influence both floe growth, size and settling velocities. Combining these results with real-time data on sediment concentration, particle size distribution, turbidity, and flow dynamics can be helpful to make dredging decisions, reduce the environmental disruption, and guide dredging equipment selection. By understanding the factors that influence sediment flocculation, deposition, and resuspension, we can design engineered solutions to mitigate the impact of turbidity current.
...
The insights gained from deep-sea mining (DSM) research regarding sediment dynamics can be utilized to better predict turbidity plumes in shallow marine environments. Small-scale lab experiments can replicate deep-sea conditions effectively, offering an ideal model system to study turbidity currents, given the reduced hydrodynamics and low biota present in the deep sea. DSM operations involve the deployment of a Polymetallic Nodule Mining Tool (PNMT) that collects ore and discharges excess water and sediments. Organic matter, bound to mineral clay as floes, is a key driver of sediment transport in the deep sea. Understanding the dispersal and settling patterns of sediments, and the likelihood of flocculation occurring in DSM activities, can be generalized and applied to turbid flows in shallow water areas. Laboratory experiments demonstrate that the interaction between organic matter, mineral clay, and floes within turbidity currents, results in the reduction of their dispersion. Alongside this, factors like shear rate and sediment concentration significantly influence both floe growth, size and settling velocities. Combining these results with real-time data on sediment concentration, particle size distribution, turbidity, and flow dynamics can be helpful to make dredging decisions, reduce the environmental disruption, and guide dredging equipment selection. By understanding the factors that influence sediment flocculation, deposition, and resuspension, we can design engineered solutions to mitigate the impact of turbidity current.
Journal article
(2024)
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Floor P. Bakker, Solange van der Werff, Fedor Baart, Alex Kirichek, Sander De Jong, Mark van Koningsveld
Reducing waiting times is crucial for ports to be efficient and competitive. Important causes of waiting times are cascading interactions between realistic hydrodynamics, accessibility policies, vessel-priority rules, and detailed berth availability. The main challenges are determining the cause of waiting and finding rational solutions to reduce waiting time. In this study, we focus on the role of the design depth of a channel on the waiting times. We quantify the performance of channel depth for a representative fleet rather than the common approach of a single normative design vessel. The study relies on a mesoscale agent-based discrete-event model that can take processed Automatic Identification System and hydrodynamic data as its main input. The presented method’s validity is assessed by hindcasting one year of observed anchorage area laytimes for a liquid bulk terminal in the Port of Rotterdam. The hindcast demonstrates that the method predicts the causes of 73.4% of the non-excessive laytimes of vessels, thereby correctly modelling 60.7% of the vessels-of-call. Following a recent deepening of the access channel, cascading waiting times due to tidal restrictions were found to be limited. Nonetheless, the importance of our approach is demonstrated by testing alternative maintained bed level designs, revealing the method’s potential to support rational decision-making in coastal zones.
...
Reducing waiting times is crucial for ports to be efficient and competitive. Important causes of waiting times are cascading interactions between realistic hydrodynamics, accessibility policies, vessel-priority rules, and detailed berth availability. The main challenges are determining the cause of waiting and finding rational solutions to reduce waiting time. In this study, we focus on the role of the design depth of a channel on the waiting times. We quantify the performance of channel depth for a representative fleet rather than the common approach of a single normative design vessel. The study relies on a mesoscale agent-based discrete-event model that can take processed Automatic Identification System and hydrodynamic data as its main input. The presented method’s validity is assessed by hindcasting one year of observed anchorage area laytimes for a liquid bulk terminal in the Port of Rotterdam. The hindcast demonstrates that the method predicts the causes of 73.4% of the non-excessive laytimes of vessels, thereby correctly modelling 60.7% of the vessels-of-call. Following a recent deepening of the access channel, cascading waiting times due to tidal restrictions were found to be limited. Nonetheless, the importance of our approach is demonstrated by testing alternative maintained bed level designs, revealing the method’s potential to support rational decision-making in coastal zones.
Smart, sustainable, and circular port maintenance
A comprehensive framework and multi-stakeholder approach
Ports and waterways are key in supporting the waterborne supply chains that form the backbone of global trade. Maintaining adequate water depth is vital for accessibility and safe navigation. Port authorities and contractors are the key players in developing maintenance strategies, and they strive for a mutually beneficial compromise. Port authorities aim to optimize port performance while keeping costs and delays at acceptable levels. Contractors aim to optimize the use of equipment and execution strategies to achieve cost-effectiveness and time efficiency. While minimum cost and duration are common and simple decision criteria, there is growing societal pressure to incorporate smart, sustainable, and circular elements. However, these elements are less straightforward to interpret and there is a lack of a comprehensive framework to quantify smart, circular, and sustainable strategies. This lack of clarity presents significant challenges in balancing traditional and emerging objectives in port maintenance. Our study directly addresses this gap by providing a structured approach to decision-making that integrates these critical but complex elements. As a result, trade-offs on these important issues are harder to achieve reducing the contributions of port authorities and contractors. This study addresses this gap by applying the Frame of Reference (FoR) method to extract objectives and indicators for decision-making from both the port authorities' and contractors' perspectives. We fill in the prescribed elements of the basic FoR template through a systematic literature review (SLR), clarifying to what extent consensus exists on these topics. The SLR revealed 128 articles and identified common strategies, research methods, influential journals, and contributing countries. Projecting these findings onto the basic FoR template showed that the protection of marine ecosystems and sediment management has received considerable attention from researchers while mitigating emissions and adopting smart techniques are emerging subjects in the literature that need further investigations. As a result, this study offers theoretical and managerial insights to improve what can be achieved with smart, circular, and sustainable maintenance strategies, while identifying crucial remaining knowledge gaps.
...
Ports and waterways are key in supporting the waterborne supply chains that form the backbone of global trade. Maintaining adequate water depth is vital for accessibility and safe navigation. Port authorities and contractors are the key players in developing maintenance strategies, and they strive for a mutually beneficial compromise. Port authorities aim to optimize port performance while keeping costs and delays at acceptable levels. Contractors aim to optimize the use of equipment and execution strategies to achieve cost-effectiveness and time efficiency. While minimum cost and duration are common and simple decision criteria, there is growing societal pressure to incorporate smart, sustainable, and circular elements. However, these elements are less straightforward to interpret and there is a lack of a comprehensive framework to quantify smart, circular, and sustainable strategies. This lack of clarity presents significant challenges in balancing traditional and emerging objectives in port maintenance. Our study directly addresses this gap by providing a structured approach to decision-making that integrates these critical but complex elements. As a result, trade-offs on these important issues are harder to achieve reducing the contributions of port authorities and contractors. This study addresses this gap by applying the Frame of Reference (FoR) method to extract objectives and indicators for decision-making from both the port authorities' and contractors' perspectives. We fill in the prescribed elements of the basic FoR template through a systematic literature review (SLR), clarifying to what extent consensus exists on these topics. The SLR revealed 128 articles and identified common strategies, research methods, influential journals, and contributing countries. Projecting these findings onto the basic FoR template showed that the protection of marine ecosystems and sediment management has received considerable attention from researchers while mitigating emissions and adopting smart techniques are emerging subjects in the literature that need further investigations. As a result, this study offers theoretical and managerial insights to improve what can be achieved with smart, circular, and sustainable maintenance strategies, while identifying crucial remaining knowledge gaps.
This article discusses whether or to what extent flocculation plays a role in the saline deep-sea environment and whether sediment plumes generated by deep-sea mining activities are affected by the process of flocculation. The results of our laboratory study demonstrate that deep sea mineral clay with a median floc size of 20 μm can flocculate quickly within 2.5 min of mixing to form flocs with a median floc size of about 50–150 μm and outliers as large as 500 μm in size due to the presence of natural organic matter. At high shear (turbulent mixing), a threshold of about 125 s−1 was found above which, organic matter can successfully bind to clay. Above 125 s−1, the steady-state floc size is also found to increase linearly with shear. In low energetic conditions (when flocs experience mainly differential settling), the median floc sizes are found to be 2 or 3 times larger than at turbulent mixing. As expected, the rate of flocculation is greater at higher clay concentrations. At long mixing times, the median floc size is found to decrease due to the breaking/reconformation of flocs. Experiments performed to study the ageing of flocs at rest demonstrated that a dynamic process was ongoing between the organic matter and the clay. It is hypothesized that the organic matter present has amphiphilic properties. Over time, the organic matter would rearrange itself such as to maximize its contact area with the mineral clay, resulting in two effects, depending on the structure of the flocs. In the case of flocs formed at high shear, it led to a rupture of flocs. A slow agitation of settled flocs, having previously experienced low shear conditions, on the other hand, led to aggregation. Overall, the results found in the present article show that flocculation likely plays a significant role in deep-sea areas.
...
This article discusses whether or to what extent flocculation plays a role in the saline deep-sea environment and whether sediment plumes generated by deep-sea mining activities are affected by the process of flocculation. The results of our laboratory study demonstrate that deep sea mineral clay with a median floc size of 20 μm can flocculate quickly within 2.5 min of mixing to form flocs with a median floc size of about 50–150 μm and outliers as large as 500 μm in size due to the presence of natural organic matter. At high shear (turbulent mixing), a threshold of about 125 s−1 was found above which, organic matter can successfully bind to clay. Above 125 s−1, the steady-state floc size is also found to increase linearly with shear. In low energetic conditions (when flocs experience mainly differential settling), the median floc sizes are found to be 2 or 3 times larger than at turbulent mixing. As expected, the rate of flocculation is greater at higher clay concentrations. At long mixing times, the median floc size is found to decrease due to the breaking/reconformation of flocs. Experiments performed to study the ageing of flocs at rest demonstrated that a dynamic process was ongoing between the organic matter and the clay. It is hypothesized that the organic matter present has amphiphilic properties. Over time, the organic matter would rearrange itself such as to maximize its contact area with the mineral clay, resulting in two effects, depending on the structure of the flocs. In the case of flocs formed at high shear, it led to a rupture of flocs. A slow agitation of settled flocs, having previously experienced low shear conditions, on the other hand, led to aggregation. Overall, the results found in the present article show that flocculation likely plays a significant role in deep-sea areas.