Surveying and Monitoring

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.

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.

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.

As regular maintenance and relocation of sediment deposits are highly expensive, Port authorities seek more efficient solutions for reducing the costs and CO2 emissions of maintenance dredging. One solution, water injection dredging (WID), is carried out for maintaining the sediment deposits which predominantly consist of clay and silt. WID has been proven to be a cheaper solution by leaving the sediment in place, eliminating substantial costs for relocation of the dredged sediment.

Winning co-author Liesbeth De Keukelaere the Young Author Award, an article about the pilot test case organised at the Prins Hendrik Zanddijk project in Texel, The Netherlands, demonstrating drone technology for water quality monitoring.

IADC’s Young Author Award winner François De Keuleneer and co-authors Joris de Vroom and Arjan Mol discuss the Workability Tool which ensures captains of specialised vessels can make informed decisions to dredge during favourable wave conditions.

Dredging activities often result in the suspension of sediment into the water column in the vicinity of the activity. Sediment release to the aquatic environment and the effects of this release are often the prime environmental concern associated with dredging.

The continuing surge in vessel sizes is putting increased pressure on port authorities worldwide. Experts recount the implementation of innovative modelling for maintaining channel depths at the ports of Brisbane and Geelong, Australia.

To show the success of polymer use in highly contaminated areas, two recent projects are presented: at Port-La-Forêt harbour in La Forêt-Fouesnant, France and at the Kishon River seven kilometres downstream from Haifa, Israel.

Randle Reef at Hamilton Harbour, an Area of Concern (AOC), is the largest site in Canada contaminated with Polycyclic Aromatic Hydrocarbons (PAHs). A collaboration of municipal and federal entities is working on remediation measures.

Multicopters, unmanned aerial surveyors, can fly and take pictures in difficult-to-reach or potentially dangerous areas, improving the speed and safety of acquiring data.

TNO’s acoustic surveys of dredgers during all phases of the dredging cycle showed that permanent hearing threshold shift was not exceeded in any cases studied or in any species in question.

Removing sediments with high dioxin concentrations requires extra care, with modern surveying and tracking techniques from beginning to end, from dredging to a high-tech dewatering process to the final disposal.

A review of survey and monitoring techniques as well as specialised environmental systems are realised in an "ideal" vessel.

The Fact Sheet "Beneficial Use of Dredged Material" describes methods and answers questions about how to deal with large quantities of sediments in relation to dredging projects and ecological developments

The Fact Sheet "Environmental Monitoring” describes the methods used to alert dredging contractors to environmental impacts so they can be addressed quickly.

“Facts About Underwater Surveys” describes why surveys are crucial to a well-executed dredging project and the technologies and instruments being used.

IADC presents a series of interactive free live webinars with experts from the dredging sector. Topics discussed are all based on high-profile projects.