Dredging for the Offshore Industry: Environmental Management Strategies

Abstract

Projects related to the offshore industry are often involved with the realization of complex infrastructures in sensitive marine environments. These projects show serious concerns about the preservation of environmental values, strong demands on assessment of impacts, strict controls on work methods and extensive monitoring programs during project realization. Generally, the contractor is responsible for minimizing the environmental impacts caused during project realization. Various impacts relate to dredging operations. This has readily inspired Royal Boskalis Westminster NV to develop a series of innovations aiming to mitigate the direct impact of dredging activities. Sustainable and cost-efficient realization of such projects can only be achieved on the basis of thorough understanding of dredging processes and their impact on the natural environment and state of the art environmental management and monitoring strategies. Turbidity increase is the most common environmental effect of dredging operations. Boskalis has recently been involved in various projects (e.g. the construction of LNG terminals and pipeline-landfalls) that involved stringent limits to dredge-induced turbidity. By applying preparatory numerical environmental modeling, real-time monitoring control and implementing strict environmental management procedures Boskalis has proven to be able to control the impact of dredging works and realize complex projects in a sustainable and cost-efficient manner. From these recent projects, various lessons were learned that helped to improve the management of environmental impact related to dredging works. These lessons are:Each project is unique. Restrictions and lessons learned at one project should be used with great care for the next project;Dredging-induced impacts should be evaluated for each project in relation to the surrounding ecosystem. Environmental restrictions should be based on the resilience of the local ecosystem, while accounting for natural fluctuations;Monitoring programs should be designed in an adaptive manner, to allow for review of the procedures and make adjustments if appropriate;Environmental monitoring should be integral part of project planning, to avoid unforeseen delays and costs. Recent projects have demonstrated Boskalis' capability to successfully apply complex environmental monitoring strategies in present-day dredging practise. When communicated to the outside world, monitoring data were found to facilitate stakeholder involvement and public information purposes. In this way, environmental monitoring is of direct relevance for the success of marine infrastructure projects and their appreciation by the general public.