Dredging in sensitive environments Using smart models to manage costs and impacts
Type:
Presented during:
WODCON XVII: "Dredging in a Sensitive Environment" - 2004, Hamburg, Germany
Authors:
Ross Fryar, Ivan Botev, Riku Koskela and Joanna Lee
Abstract: Dredging associated with the development and maintenance of infrastructure within sensitive coastal and estuarine environments offers a series of unique challenges. In many cases, construction works such as dredging clearly have the potential to be invasive, with unmanaged deteriorations in water quality adversely impacting aquatic flora and fauna. The application of hydrodynamic models offers a means to predict dredging impacts before they occur, thereby allowing an effective management program to be developed and tested prior to the commencement of dredging. The key element is the level of understanding of physical processes that can and should be obtained.
Furthermore, once a model is established, it can then be readily applied to the assessment and management (read environmental protection) of an entire coastal system, including estuaries and bays. Examples include the assessment of navigability, oil spills, nutrient cycling and habitat protection.
An added benefit of adopting a rigorous modelling approach such as this is the potential to better predict ongoing sedimentation, thereby allowing the assessment of maintenance dredging requirements, and of the feasibility of locating infrastructure appropriately, so as to avoid excessive siltation and hence high annual maintenance costs.
Models have been developed for two major Australian ports in northern Australia, at Darwin and Townsville. In both cases, the development or application of a rigorous model has allowed high levels of understanding of adjacent coastal waters, thereby facilitating a well managed dredge program (Darwin) and the potential to reduce the annual dredging cost in confined areas (Townsville). Links to the application of recent innovations in the integration of modelling and monitoring are also discussed.
Keywords: dredge monitoring, hydrodynamics, predictive modelling, predictive monitoring.