Limiting global warming requires the maritime sector to transition to a more efficient and sustainable operation. Reducing greenhouse gas (GHG) emissions, such as carbon dioxide and methane is vital to limit the global temperature rise (IPCC, 2021). Several legislative initiatives are in effect or are being discussed, including the IMO GHG strategy and the FuelEU Maritime initiative. This article discusses the potential of waste heat recovery (WHR) technologies to reduce the fuel consumption of dredging vessels. Available WHR technologies are compared based on working principle and operational performance for different types and ratings of internal combustion engines.

The challenge of maintaining harbours and ports while conserving and sustaining coastal habitats, with all the rich resources they provide, requires that port and harbours do more to develop approaches to maintenance dredging that provide benefit to these neighbouring habitats. In this article, we describe an example from Harwich Harbour in the UK where Harwich Haven Authority (the Conservancy Authority) is looking to move to a more nature-based maintenance dredging methodology, using agitation dredging. Using the results of monitoring and sophisticated numerical modelling, we evaluate the likely benefit to the Stour/Orwell intertidal areas arising from the use of the agitation dredging.

In the 2015 Paris agreement, countries committed to implementing measures to reduce greenhouse gas emissions to limit global warming. For the maritime industry specifically, the International Maritime Organization (IMO) has proposed measures for energy efficiency of vessels and candidate measures regarding fuel choice and speed optimisation. This article aims to contribute to the latter by showing how logistical simulations can be used to optimise fleet operations. We will illustrate this in the form of a conceptual case using one cutter and a range of barge fleets. Running simulations with all possible fleets, we will demonstrate the value of extra energy-based alternatives to challenge the fastest, cheapest and most flexible alternatives.

Frank Verhoeven, President of IADC, shares his thoughts on todays’ issues related to the dredging industry and introduces the articles in this issue of Terra et Aqua.

Frank Verhoeven, President of IADC, shares his thoughts on todays’ issues related to the dredging industry and introduces the articles in this issue of Terra et Aqua.

Complex construction projects that use traditional procurement practices are often impacted by significant cost overruns and delays. Early contractor involvement (ECI) is a concept that strives to involve the contractor collaboratively at an early stage of a project’s development to mitigate or otherwise eliminate those risks. In August 2022, PIANC published the report “A framework for early contractor involvement in infrastructure projects” to help industry practitioners in choosing and best implementing ECI. This article is intended to develop on key aspects of the PIANC report and look at the factors that can lead to a successful maritime ECI project.

Numerical models are often used to predict the magnitude and behaviour of dredge plumes to help assess and manage any environmental risks. To provide a realistic prediction of plumes resulting from dredging, numerical models require information on the rate at which sediment is suspended by the dredging, along with the characteristics of the suspended sediment. Previous investigations have shown that in the marine environment, fine-grained sediment suspended by natural processes and dredge-related activities are typically present as aggregated particles known as flocs. This article considers the importance of including the process of flocculation in dredge plume models.

Steel and concrete are the most common materials used in quay wall structures. The application of these materials contributes to a high emission of greenhouse gasses such as CO2 and the materials make up a large part of the construction costs. This graduate research examines whether alternative quay wall structures have the potential to be more cost effective and more sustainable compared to conventional structures for inland ports. An innovative quay wall of reinforced soil was designed and quay elements implemented to make a quay wall structure. A comparison was then made based on the criteria costs and sustainability between the innovative quay design and two conventional quays.

DEME is very proud that its retractable ladder, specifically designed for hydraulic track excavators, won the prestigious IADC Safety Award 2022, and especially because the design of this invaluable piece of safety equipment is now being shared with other IADC members.

Marine dredged sand and gravel make an important contribution to regional supplies of building materials used in England. Marine aggregate dredging however, is known to result in effects to the receiving environment which, if not properly controlled, could cause adverse impacts to a wide range of receptors. As the marine area around England gets busier, competition for space comes with regulatory challenges and an integrated marine management approach that uses a robust planning system is required. This article discusses the regulation of aggregate dredging in England and provides an overview of the sector’s importance in providing primary aggregate.

A fixed and direct transport connection between Scandinavia and Central Europe has been an enduring vision for many decades. This vision is about to be realised with the construction of the Fehmarnbelt Fixed Link, an 18-kilometre-long immersed tunnel between Rødbyhavn in Denmark and Puttgarden in Germany. When it opens in 2029, the tunnel will be the longest immersed tunnel in the world combining a dual railway and motorway connection. This article provides insight into the improved dredging equipment used and the methodology specially adapted and further developed to the project’s requirements.

Green solutions in ports, waterways and coastal projects have increasingly become available thanks to many years of research and pioneering efforts in practice. These sustainable and/or nature-based solutions have shown to be good alternatives for classic solutions, but application is far from mainstream yet. One of the major hurdles is the lack of access of private capital to finance these kinds of solutions despite the strong interest of capital markets in green infrastructure opportunities. Identifying the hurdles and paving a way forward to overcome these hurdles could therefore help to increase the uptake of those green solutions.

Frank Verhoeven, President of IADC, shares his thoughts on todays’ issues related to the dredging industry and introduces the articles in this issue of Terra et Aqua.

Frank Verhoeven, President of IADC, shares his thoughts on todays’ issues related to the dredging industry and introduces the articles in this issue of Terra et Aqua.

Sediment erosion is a phenomenon of mechanical wear of components that decreases efficiency and uptime of the dredging process. Dredge pumps are designed to handle mixtures of water and solid particles with varying particle size from less than 0.002 mm to greater than 200 mm. A dredge pump’s overall effectivity in the field depends upon its uptime. Uptime is influenced by the number of times the pumping process is interrupted, which can be due to maintenance combating the material loss, clogging, etc. This research deals with the erosion phenomena by considering a framework of numerical models, capable of qualitative and quantitative erosion estimation, coupled with experiments for validation. Coordinate Measurement Machine (CMM) is used for surface roughness measurement before and after the experiment, thus depicting the material loss due to erosion.

When individual employees, teams and companies view everyday processes and situations through a continuous lens of safety, they can each contribute to making all aspects of operational processes, whether on water or land, safer. For the 2022 Safety Awards, IADC’s Safety Committee received 11 submissions. Each one is assessed on five different categories; sustainability; level of impact on the industry; simplicity in use; effectiveness; and level of innovation.

The planet is facing enormous challenges caused by human activity, increasing the vulnerability of communities and ecosystems to the forces of nature. This is worsened by the effects of climate change, which is threatening the world’s coastal defences. Van Oord has responded to these challenges by developing the Climate Adaptation Action Plan. The plan is designed to encourage meaningful dialogue between stakeholders in order to provide ready-to-scale marine solutions that help increase the resilience of the communities and ecosystems of coastal areas.

As IADC celebrates 50 years of its quarterly journal, it seemed only fitting to speak to its longest standing editor, Marsha Cohen, who stood at the helm of Terra et Aqua for 25 years. We caught up with her at her home in Florida to talk about the highs, the lows and a good dose of serendipity.

This article reviews various court cases over the past 50 years and considers their influence on marine infrastructure contracts and the allocation of risk between contract parties. The establishment of case law and legal precedent is an ever-evolving process, it being dependent on claimants to put their disputes through the court process to seek the outcome they desire. It is often a long and costly process. The rise of adjudication in various common law jurisdictions and countries means that often disputes are resolved without recourse to the courts and various industry standard contracts have arbitration as the final and binding mechanism to resolve disputes.

It is hard to imagine a time when safety was not deemed important, when Personal Protective Equipment (PPE) was not used and little was done in the way of prevention. A few decades ago, occupational health and safety was not considered as important for the vast majority of companies. Instead, incidents and emergencies were handled as they occurred, as effectively as possible given the limited technology and resources available. Today, those times have changed. This article explores the progress of health and safety in the dredging industry and QHSSE professionals, Ton van de Minkelis and Christophe Leroy share their experiences in building a proactive safety culture.

Each year, at selected conferences, the Conference Paper Committee is asked to recommend a prize winner whose paper makes a significant contribution to the literature on dredging and related fields. Since 1987, IADC has presented 42 Young Author Awards. Curious to see where they are now, we asked previous winners what impact winning the award had on them and their career.

The effect of density waves and slurry dynamics on slurry pipeline flow assurance cannot be predicted with current slurry pipeline design methods. Current methods are based on steady-state assumptions, assuming that the mixture velocity and density are constant in time and in the pipeline. Therefore, using current design methods a dynamically stable pipeline cannot be guaranteed. Furthermore, new experiments in vertical pipelines show that density wave amplification is possible at mixture velocities far above the critical velocity. This article presents a new temporal design method based on 1D Driftflux CFD, which is able to model growing density waves.

During his distinguished career as professor of Coastal Engineering at Delft University of Technology (TU Delft), Kees d’Angremond served as head of Hydraulic and Offshore Engineering, chair of the department of Hydraulic and Geotechnical Engineering, and dean of the faculty of Civil Engineering from 1989 to 2001. Now professor emeritus, he still works as an advisor and independent consultant. We invited Kees to a conversation with Stefan Aarninkhof, professor of Coastal Engineering and chair of the department of Hydraulic Engineering at TU Delft, to talk about their careers in the dredging industry and the role of academia in the industry today.

Frank Verhoeven, President of IADC, shares his thoughts on todays’ issues related to the dredging industry and introduces the articles in this issue of Terra et Aqua.

The use of nature and natural processes is an innovative way to increase water safety and create added value through nature development and recreation. This exploratory study provides an initial inventory of the impact and costs of existing Building with Nature projects in the Netherlands. It also includes an analysis of the decision-making process in choosing this type of project and identifies success factors. Building with Nature projects deliver added value but often also involve additional costs compared to traditional reinforcements. These costs give an indication of what we as a society are prepared to pay for the development of nature and recreation as part of hydraulic engineering projects.

IADC’s Safety Committee and Board of Directors awarded the very first Safety Award to a supply chain organisation active in the dredging industry to Keppel FELS. The company was praised by the committee for the results of its safety programme and commitment to safety onsite. Anchored in Keppel Offshore & Marine’s Safety Plus Programme and Singapore's National WSH Vision 2028, Keppel FELS continues to consistently improve and enhance its existing Health, Safety and Environment (HSE) management systems.

During marine transfers, it is essential to achieve a maximum level of control. With the bollard step, Jan De Nul has designed a simple solution to enhance safety during transfers of crew and visitors. This innovative idea came from the crew of the multicat DN46 and was picked up during an Operational Control meeting, where an advisory board discusses suggestions that improve the safety and efficiency of the company’s operations. ‘We stimulate all possible innovative ideas within our company’, says Quinten Schaumont, Area QHSSE advisor. ‘At all levels, at all times.’

Climate change and increasing environmental damage are demonstrating the urgency of transformation to a sustainable global economic model. The implementation of the sustainable development concept tends to narrow to integrating environmental, social, and economic concerns in the decision making. In economics, the definition of such concerns is an externality that represents the divergence between social and private costs. This study investigates the available sustainable asset valuation methods that can include the externalities materialised in maritime infrastructure projects and compares them based on economic, social and environmental criteria.

In today’s world, expectations for sustainable practices are fast becoming the norm. Countries, the public and communities are requesting transparency, the application of higher environmental standards and involvement in decision-making processes when new developments in a marine environment are proposed. Marine infrastructure projects not only require environmental permits and works licences to be in place, they also need a Social Licence to Operate (SLO). This article describes the social licence in this fast-changing context of information and technology, and explores tools that can be used to develop a ‘responsible project’ and provide a successful and sustainable outcome for society and the environment.

This high-level report explores what is needed in order to improve the connection between green-labelled funds and sustainable waterborne infrastructure projects.

Frank Verhoeven, President of IADC, shares his thoughts on todays’ issues related to the dredging industry and introduces the articles in this issue of Terra et Aqua.

Frank Verhoeven, President of IADC, shares his thoughts on todays’ issues related to the dredging industry and introduces the articles in this issue of Terra et Aqua.

A full consideration of ecosystem services (ES) impacts, interactions and improvements can result in more sustainable and adaptive solutions for dredging and marine construction projects. Furthermore, the benefits can be translated in monetary terms, providing returns on investment and highlighting the links between ecology and economy. For some however, the ES concept is too theoretical. This article seeks to show how the ES concept can actively be applied at any point during a project and the benefits of doing so. Its purpose is to provide a framework for integrated and interdisciplinary thinking throughout the different steps of the project cycle.

When individual employees, teams and companies view everyday processes and situations through a continuous lens of safety, they can each contribute to making all aspects of operational processes, whether on water or land, safer. For the 2021 Safety Awards, IADC's Safety Committee received 15 submissions. Each one is assessed on five different categories; sustainability; level of impact on the industry; simplicity in use; effectiveness; and level of innovation.

As increasing greenhouse gas (GHG) emissions contribute to global warming, it is becoming more important to consider the carbon footprint of hydraulic engineering projects. This carbon footprint is more complex than previously thought however, as it can also include the carbon dynamics of the sediments from which projects are built. The purpose of this study was to provide a first approximation from sediment-related GHG emissions of dredged sediments. Using the case study of the clay ripening pilot project (‘Kleirijperij’) in Groningen, the Netherlands, one phase of sediment processing was examined: the ripening of dredged sediments for use as a clay material in dyke construction.

The development of a new marine project demands a system approach in which all aspects, including technical, economic, environmental and social, are considered and integrated equally and at an early stage. While insufficient information may be available to make informed decisions, choices need to be made to progress a project, assess impacts and risks, and engage stakeholders. This article explores the case of a new port terminal in Amatique Bay, Guatemala. A method was developed to assess, at an early stage, the potential negative impacts on seagrass habitats from the disposal of dredged material at different locations, while having limited real-time and location-specific information at hand.

Taking a fresh look at traditional, unsustainable coastal defence methods. A pioneering project discovers some inspiring concepts, including using biogenic reefs for ecosystem-based flood defence.

‘It’s clear that the solutions that we employed in our approach to engineering in the 20th century are not aging well.’ As National Lead for the Engineering With Nature initiative, Dr Todd Bridges discusses how we must have a diversified solution set in which nature is a part of the solution.

A major mechanical property of clay is the adhesion factor that reflects the ratio between its cohesive and adhesive strength under different water content.

Frank Verhoeven, President of IADC, shares his thoughts on todays’ issues related to the dredging industry and introduces the articles in this issue of Terra et Aqua.

Continuing the ‘seeing is believing’ approach, this second volume presents Engineering With Nature principles in action through 62 projects from around the world.

In the past decade, there have been noteworthy advances in case law with respect to adverse physical conditions as well as the development and use of digital ground models that have become more widespread. This article looks at the development and changes in risk profiles that may result due to these two developments.

Over the past decades, there has been a growing interest in exploring innovative ways to minimise the environmental footprint of coastal developments and in nature-based approaches for shoreline protection. At Mubarraz Island near Abu Dhabi (UAE), an international oil company beneficially reused ~12 million m³ of dredged material to protect pipelines, construct a causeway and create mangrove habitat to manage coastal erosion. This ‘Working with Nature’ approach has provided a cost-effective nature-based solution for shoreline protection, with added benefits for biodiversity conservation.

In June 2019, the research team of the LIFE MARINAPLAN PLUS project began operating the first-of-a-kind demonstration plant installation at the harbour entrance of Marina di Cervia (Italy). Fulfilling the project’s objective to apply at industrial scale a reliable technology for the sustainable management of sediment in marine infrastructures, this technology prevents harbour silting through the use of submerged devices called ‘ejectors’ installed on the seabed.

At Deltares in the Netherlands, a research team is developing a portfolio of technologies dedicated to the management of the finest and most challenging fraction of soft sediments. These technologies may unambiguously be called nature based because they make use of natural processes to enhance dewatering and strengthening, induce flocculation and the settling of fines, and protect the muddy bed from erosion.

Managing sediments, especially from dredging, is important for the management of estuaries and coastal areas. When implemented in the right way, a sediment management strategy can be qualified as a nature-based solution as it uses the physical processes of erosion and sedimentation to create added value. There is a need for an evaluation of sediment strategies and the habitats that are created for a wider range of objectives than only biodiversity and nature conservation. The concept of ecosystem services provides this broader framework.

Stéphanie Groen works as the Director of Coastal & Climate Change, Asia for Aurecon. Based in Singapore, she was appointed to the position at the beginning of 2020. Previously, Stéphanie was involved in marine and environmental projects for more than 15 years with DHI and her education is in civil engineering and business administration. IADC also knows Stéphanie as the winner of the Young Author Award in 2007. More recently, she was appointed as a committee member to the prestigious FIDIC Sustainable Development Committee. We were interested to hear more from Stéphanie – her views on sustainability, the collaboration with the dredging industry through FIDIC and what her new role can mean for sustainable water infrastructure projects.

At present too little use is made of the opportunities that the design and construction of land reclamation offer for the underground storage and recovery of fresh water. The managed aquifer recharge systems in the coastal dunes of the Netherlands are a good example of successful subsurface water storage. And it is to be expected that the sandy deposits of land reclamations could serve a similar purpose. This in turn will contribute to a sustainable development of land reclamations.