The future of maintenance dredging: working with nature? A synthesis

The concept of ‘Working with Nature’ is now well established (PIANC, 2008 and 2011) and has been demonstrated by numerous capital dredging and marine construction projects, however, it is also a concept that can be applied to maintenance dredging. In the past it has been shown that the majority of material that arises from dredging operations, including maintenance material, is sent to designated offshore placement sites (e.g. EuDA, 2005). By design, the dredge material placement sites are often located outside the boundary of the relevant sediment transport system; in other words, ‘offshore and out of the system’. Displacing maintenance dredge material in this way can significantly affect the local and regional sediment budget, which in-turn can lead to potential (negative) morphological and ecological impacts. This paper discusses how the concept of ‘Working with Nature’ can be applied to maintenance dredging projects by considering: the effect of maintenance dredging on sediment budgets, examples of where ‘Working with Nature’ has been applied to maintenance dredging activities (including the use of different dredging techniques) and the potential issues that may be encountered in its application and how they can be overcome