Strategies for reducing dredging impacts on Port development: The Portsmouth Design & Construct Case

27-28 October 2016, Lisbon, Portugal

J. Fernandes, Boskalis, The Netherlands

Capital dredging of the Portsmouth harbour, berth pocket, turning circle and approach channel is required to allow for the seaborne access of the new Queen Elizabeth Class aircraft carriers. 

Dredging operations are needed in close vicinity of sensitive stakeholders particularly, the historical heritage of old Portsmouth, the recreational marinas and docks of the Port and the protected Ramsar area.

Strategies to mitigate the social, economical and environmental impacts of the works on those assets were created in close cooperation with the Client and successfully implemented:

(i) Management strategy to deal with the structures in the narrows consisting of a risk assessment, gap analysis and demonstration of the overall slope stability after dredging

(ii) Overall dredging strategy using combination trips, maximizing the cycle period, with no overspill through overflow within the harbour and continuous turbidity monitoring at the access channel

(iii) Design of dredged slopes ensuring no encroachment into the Ramsar area by surveying prior to dredging and considering additional safety in design

Boskalis was awarded the design & construction contract after a competitive  dialogue procedure during which the proposal of these strategies were key for the successful outcome.

Last update: 19 October 2016