Since dredging often represents a significant portion of the opex and capex costs associated with maritime infrastructure, dredging optimisation is something that owners, operators and developers increasingly need to focus on, says Mark Lee, HR Wallingford’s Dredging Group Manager.
In simple terms, optimisation is about identifying, quantifying and implementing efficiency savings. Dredging is a key target for optimisation because of its significance as a cost and its highly technical nature, which can make it difficult for those managing the operation of infrastructure or its construction to see efficiency gains clearly.
What’s more, optimisation often results in additional benefits such as reduced environmental impacts as a consequence of less dredging or more effective dredging. This means it is also of interest to regulators, fisheries representatives and local residents and not just the project owner.
The opportunity to optimise dredging can be identified at any stage of a project’s cycle, for example:
• At the design stage. By examining the navigational and operational requirement of the facility in order to minimise the dredging requirement. This can reduce costs and the impact footprint of the project.
• On tendering and construction. Determining the most appropriate and efficient dredging method by assessing the dredging plant type and capability, and preparing a dredging contract package tailored to the project’s specific needs. This can lead to a reduction in overall project costs, as well as ensuring compliance with any imposed regulatory conditions whilst attracting competitive bids.
• During operation. By determining the most efficient maintenance dredging strategy with respect to the project’s commercial need and timings. For example, can the area requiring dredging be reduced? Can the dredging be done better/cheaper? As well as reducing overall ongoing costs, this ensures efficient operation of the facility.
HR Wallingford, has recently completed projects for port terminal operators, where dredging optimisation was vital to the overall project success. Optimisation of the dredged areas’ extents and depths was performed using navigation simulations and sedimentation modelling, along with a tidal depth availability assessment and detailed analysis of historic sedimentation patterns. Support was provided through to completion of the works, with on-site support ensuring the contract, specification and schedule were met.
Mark Lee, HR Wallingford’s Dredging Group Manager, says: In combination, these steps can ultimately lead to a significant reduction in the overall required dredge volume and improvements in dredging efficiency. Given that savings of the order of $4m have been realised to individual projects for individual maintenance dredges, whilst maintaining a safely navigable port, and that these savings are repeatable for future maintenance dredges, it’s understandable that dredging optimisation is something that developers, operators and owners of maritime projects increasingly want to focus on.”
HR Wallingford has provided site supervision on some of the world’s largest dredging projects, including DP World’s London Gateway Port development in the UK and the Ichthys, Gladstone and Wheatstone LNG projects in Australia.