Modelling of sediment dispersion due to maintenance dredging

Period:	08/2008-05/2009
Location:	Lough Foyle, Ireland
Client:	Londonderry Port and Harbour Commissioners

assignment/short description

The Londonderry Port & Harbour Commissioners, North Ireland (NI), proposes to use their own dredging vessel (Lough Foyle) to maintain the navigation channel through Lough Foyle instead of using a contractor to perform this work. This will result in the need to discharge a significantly larger amount of dredged material at the Lough’s dedicated spoil site than it is the case with the contractor, who discharged the majority of the dredged material offshore. Instead of having a contractor performing the maintenance dredging in a matter of days, the port proposes to spread the maintenance over about a half year and to discharge material as a trickle-feed at the spoil location. To obtain a FEPA disposal licence for this new dredging regime, the expected impacts on ecology, important shellfishery in the Lough, etc. have to be assessed. This study investigated sediment dispersion from the proposed disposal operations and provided an initial assessment of the possible resultant effects on ecology in Lough Foyle of the new maintenance dredging regime.

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