Alex Kirichek
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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.
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.
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.
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.
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.
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.
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).
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].
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.
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 presence of mud layers on the bottom of ports and waterways can have negative effects on the hydrodynamic behaviour of marine vessels. This numerical study investigates the effect of muddy seabeds on the full-scale resistance of an oil tanker sailing straight ahead. The objective is to determine the influence of factors such as the densimetric Froude number, UKC and mud rheology at speeds between 3 and 9 knots. The numerical study is conducted using a finite-volume Reynolds-Averaged Navier–Stokes (RANS) flow solver combined with the Volume-Of-Fluid (VOF) method to capture the mud–water interface. At certain critical speeds, the presence of mud increased the ship’s total resistance by up to 15 times compared to the case with solid bottoms. The non-Newtonian rheology of mud was found to influence the ship’s resistance mainly at low speeds and when sailing through the mud layer. This article also shows that, when sailing through mud, the computed resistance at high speeds may be underestimated because of two effects, namely ‘water lubrication’ and ‘numerical ventilation’.
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The presence of mud layers on the bottom of ports and waterways can have negative effects on the hydrodynamic behaviour of marine vessels. This numerical study investigates the effect of muddy seabeds on the full-scale resistance of an oil tanker sailing straight ahead. The objective is to determine the influence of factors such as the densimetric Froude number, UKC and mud rheology at speeds between 3 and 9 knots. The numerical study is conducted using a finite-volume Reynolds-Averaged Navier–Stokes (RANS) flow solver combined with the Volume-Of-Fluid (VOF) method to capture the mud–water interface. At certain critical speeds, the presence of mud increased the ship’s total resistance by up to 15 times compared to the case with solid bottoms. The non-Newtonian rheology of mud was found to influence the ship’s resistance mainly at low speeds and when sailing through the mud layer. This article also shows that, when sailing through mud, the computed resistance at high speeds may be underestimated because of two effects, namely ‘water lubrication’ and ‘numerical ventilation’.
Rheology of flexible fiber-reinforced cement pastes
Maximum packing fraction determination and structural build-up analysis
Journal article
(2024)
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Zhenbang Guo, Jingping Qiu, Duanping Huang, Kai Liu, Alex Kirichek, Chen Liu, Boyu Chen, Yingliang Zhao, Zhengyao Qu
The maximum packing fraction (φfm) of flexible fibers is an essential parameter for understanding the rheological behavior of flexible fiber-reinforced cement paste (FFRCP). However, direct measurement of φfm of flexible fibers is still lacking. In this study, a shear rheology-based method for direct measurement of φfm was proposed and the assumption of fiber conformation under shear was verified by micro-CT. Based on this, a yield stress model for FFRCP was constructed to explain the entanglement and friction effects in the fiber network. Finally, static yield stress tests and small amplitude oscillatory shear (SAOS) tests were carried out to explore the structural build-up of FFRCP. It was found that the proposed method enables direct determination of φfm through only a few viscosity-fiber content data for a given FFRCP. Furthermore, the proposed model can describe the static yield stress of FFRCP well. Finally, the relative structural build-up rate of FFRCP follows a similar trend as the relative yield stress, with a critical relative fiber volume fraction (0.299) as the boundary. Subsequently, the relative structural build-up gradually deviates from the relative yield stress due to the limiting effect of the fibers.
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The maximum packing fraction (φfm) of flexible fibers is an essential parameter for understanding the rheological behavior of flexible fiber-reinforced cement paste (FFRCP). However, direct measurement of φfm of flexible fibers is still lacking. In this study, a shear rheology-based method for direct measurement of φfm was proposed and the assumption of fiber conformation under shear was verified by micro-CT. Based on this, a yield stress model for FFRCP was constructed to explain the entanglement and friction effects in the fiber network. Finally, static yield stress tests and small amplitude oscillatory shear (SAOS) tests were carried out to explore the structural build-up of FFRCP. It was found that the proposed method enables direct determination of φfm through only a few viscosity-fiber content data for a given FFRCP. Furthermore, the proposed model can describe the static yield stress of FFRCP well. Finally, the relative structural build-up rate of FFRCP follows a similar trend as the relative yield stress, with a critical relative fiber volume fraction (0.299) as the boundary. Subsequently, the relative structural build-up gradually deviates from the relative yield stress due to the limiting effect of the fibers.
Journal article
(2024)
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Arash Sepehri, Alex Kirichek, Solange van der Werff, Fedor Baart, Marcel van den Heuvel, Mark van Koningsveld
Purpose: Maintenance dredging can often hinder port operations resulting in waiting times for seagoing vessels. The purpose of this paper is to investigate the dynamics between maintenance dredging activities and seagoing vessels, specifically focusing on how waiting times can be reduced. Then, the role of selecting different maintenance dredging strategies in reducing these waiting times is outlined. Methods: The study analyzes historical automatic identification system (AIS) data to identify the interaction between maintenance dredging and seagoing vessels and quantify the hindrance periods for the Mississippihaven case study in the Port of Rotterdam, the Netherlands. The trajectories of the vessels are analyzed in a simple case to show how the vessels interact and how the waiting times are quantified. The interactions are checked with the Port of Rotterdam for different port calls to ensure that maintenance dredging was the reason for these delays. Results: By analyzing the AIS data analysis of vessels in a given time window, the dredgers for maintenance work can be identified and their activities within or near the terminal can be determined. In addition, the waiting time of the seagoing vessel caused by the maintenance dredging is quantified at the terminal entrance. Conclusion: The study discusses how the maintenance dredging operations could be improved by adjusting the loading and sailing phases of maintenance dredging and provides some theoretical and managerial insights. Alternative port maintenance strategies to minimize the waiting time caused by the hindrance are also discussed.
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Purpose: Maintenance dredging can often hinder port operations resulting in waiting times for seagoing vessels. The purpose of this paper is to investigate the dynamics between maintenance dredging activities and seagoing vessels, specifically focusing on how waiting times can be reduced. Then, the role of selecting different maintenance dredging strategies in reducing these waiting times is outlined. Methods: The study analyzes historical automatic identification system (AIS) data to identify the interaction between maintenance dredging and seagoing vessels and quantify the hindrance periods for the Mississippihaven case study in the Port of Rotterdam, the Netherlands. The trajectories of the vessels are analyzed in a simple case to show how the vessels interact and how the waiting times are quantified. The interactions are checked with the Port of Rotterdam for different port calls to ensure that maintenance dredging was the reason for these delays. Results: By analyzing the AIS data analysis of vessels in a given time window, the dredgers for maintenance work can be identified and their activities within or near the terminal can be determined. In addition, the waiting time of the seagoing vessel caused by the maintenance dredging is quantified at the terminal entrance. Conclusion: The study discusses how the maintenance dredging operations could be improved by adjusting the loading and sailing phases of maintenance dredging and provides some theoretical and managerial insights. Alternative port maintenance strategies to minimize the waiting time caused by the hindrance are also discussed.
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.
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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.
Abstract: Efficient port operations require minimizing turnaround time which is the total duration of a vessel's stay in the port and encompasses waiting, maneuvering, berthing, and de-berthing times. The turnaround time can be reduced by optimizing arrivals and departures, maximizing berth availability, facilitating cargo handling, and maintaining water depth. Maintenance dredging, the primary method for maintaining water depth, is used as a continuous activity to ensure the available water depth is sufficient for the navigation of commercial (seagoing, inland, barges, etc.) vessels. The continuity of maintenance dredging interferes with commercial vessels that aim to be served in terminals. Despite the cost imposed on port authorities due to these interferences, addressing this challenge in a structured way is overlooked. To fill this gap, an open-source discrete-event model is presented in this study that employs agent-based simulation to model the interaction between seagoing and maintenance dredging processes. A simple case is proposed to provide an example of how this interaction is simulated. Then, the implications and limitations of this study are discussed and the directions for future research are recommended.
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Abstract: Efficient port operations require minimizing turnaround time which is the total duration of a vessel's stay in the port and encompasses waiting, maneuvering, berthing, and de-berthing times. The turnaround time can be reduced by optimizing arrivals and departures, maximizing berth availability, facilitating cargo handling, and maintaining water depth. Maintenance dredging, the primary method for maintaining water depth, is used as a continuous activity to ensure the available water depth is sufficient for the navigation of commercial (seagoing, inland, barges, etc.) vessels. The continuity of maintenance dredging interferes with commercial vessels that aim to be served in terminals. Despite the cost imposed on port authorities due to these interferences, addressing this challenge in a structured way is overlooked. To fill this gap, an open-source discrete-event model is presented in this study that employs agent-based simulation to model the interaction between seagoing and maintenance dredging processes. A simple case is proposed to provide an example of how this interaction is simulated. Then, the implications and limitations of this study are discussed and the directions for future research are recommended.
Sailing through fluid mud
Current advances and challenges
Instead of maintenance dredging, an alternative option for port authorities is to adapt the PIANC's nautical bottom approach. For practical purposes, the nautical bottom is defined as the level at which the fluid mud reaches either a critical density or a critical yield stress (the shear strength). These values generally correspond to a level at which the mud undergoes a so-called "rheological transition", where the density and strength of the mud increase rapidly over a short distance. Below this level, the mud becomes more and more like solid ground and is therefore no longer navigable.
Recently, new scientific and practical research has been conducted in order to gain additional knowledge on navigability in ports with fluid mud layers. In particular, a systematic rheological analysis was conducted to determine the critical limits of the yield stresses and density of fluid mud. Furthermore, a Computational Fluid Dynamics (CFD) model was developed to numerically investigate the ship-mud interaction. The model was applied to study the effects of muddy bottoms on the full-scale resistance of a modern oil tanker at speeds between 3 and 9 knots. It was confirmed that not only the density but also the yield stress of the fluid mud should be considered in the practical application of the nautical bottom. Finally, the paper discussed how the standard maintenance dredging methods can be used for producing navigable fluid mud layers. ...
Recently, new scientific and practical research has been conducted in order to gain additional knowledge on navigability in ports with fluid mud layers. In particular, a systematic rheological analysis was conducted to determine the critical limits of the yield stresses and density of fluid mud. Furthermore, a Computational Fluid Dynamics (CFD) model was developed to numerically investigate the ship-mud interaction. The model was applied to study the effects of muddy bottoms on the full-scale resistance of a modern oil tanker at speeds between 3 and 9 knots. It was confirmed that not only the density but also the yield stress of the fluid mud should be considered in the practical application of the nautical bottom. Finally, the paper discussed how the standard maintenance dredging methods can be used for producing navigable fluid mud layers. ...
Instead of maintenance dredging, an alternative option for port authorities is to adapt the PIANC's nautical bottom approach. For practical purposes, the nautical bottom is defined as the level at which the fluid mud reaches either a critical density or a critical yield stress (the shear strength). These values generally correspond to a level at which the mud undergoes a so-called "rheological transition", where the density and strength of the mud increase rapidly over a short distance. Below this level, the mud becomes more and more like solid ground and is therefore no longer navigable.
Recently, new scientific and practical research has been conducted in order to gain additional knowledge on navigability in ports with fluid mud layers. In particular, a systematic rheological analysis was conducted to determine the critical limits of the yield stresses and density of fluid mud. Furthermore, a Computational Fluid Dynamics (CFD) model was developed to numerically investigate the ship-mud interaction. The model was applied to study the effects of muddy bottoms on the full-scale resistance of a modern oil tanker at speeds between 3 and 9 knots. It was confirmed that not only the density but also the yield stress of the fluid mud should be considered in the practical application of the nautical bottom. Finally, the paper discussed how the standard maintenance dredging methods can be used for producing navigable fluid mud layers.
Recently, new scientific and practical research has been conducted in order to gain additional knowledge on navigability in ports with fluid mud layers. In particular, a systematic rheological analysis was conducted to determine the critical limits of the yield stresses and density of fluid mud. Furthermore, a Computational Fluid Dynamics (CFD) model was developed to numerically investigate the ship-mud interaction. The model was applied to study the effects of muddy bottoms on the full-scale resistance of a modern oil tanker at speeds between 3 and 9 knots. It was confirmed that not only the density but also the yield stress of the fluid mud should be considered in the practical application of the nautical bottom. Finally, the paper discussed how the standard maintenance dredging methods can be used for producing navigable fluid mud layers.
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.
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.
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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.