Environmental monitoring of a dredging project Safer Fairways to Port of Gothenburg
Type:
Presented during:
WODCON XVII: "Dredging in a Sensitive Environment" - 2004, Hamburg, Germany
Authors:
K.G. Nipius
Abstract: In the period January 2003 February 2004 the access channels to the Port of Gothenburg (Sweden) were deepened. While the dredging areas were surrounded by environmentally sensitive areas an extensive monitoring program was executed. In this paper a description is given of the Gothenburg dredging project, dredging works and environmental monitoring. Moreover the interaction between environment, monitoring and dredging activities is described. Results of the monitoring are presented and conclusions are drawn.
The purpose of the Safer Fairways to Port of Gothenburg project was to improve safety in the navigable channels. The project consisted mainly of the following components: realignment and sea bed widening, removing of shallows at the river mouth and deepening part of the harbour basins. A total of 11 Mm3 of clay was dredged and 0.5 Mm3 of rock was removed during the project. The dredging works were executed by Boskalis Westminster Dredging bv.
Strict environmental monitoring was required during the construction phase to ensure compliance with pre-set limits of water turbidity and suspended substances concentrations (SSCs). The objective of the environmental limits was to protect sensitive habitats, in particular eelgrass, mussels and soft-bottom fauna. Additional reason for the limits was to reduce the impact of the dredging on transparency and with this on the public opinion and recreation during the summer period.
The environmental limits had impact on the execution of the dredging works. The main adjustment on the dredging method to meet the limits was the reduced overflow while dredging with the TSHDs.
The Environmental Monitoring gave the Client and the public confidence on the limited impact of the dredging works to the environment. Questions from the public were easily answered by the Client due to the nearly realtime access to the Environmental Database.
Keywords: environment, monitoring, concentrations, transparency, overflow, eelgrass, mussels