This confidential project, a liquid natural gas (LNG) terminal in northern BC, is one of the largest infrastructure developments in Canada, and the largest to move to construction. For a number of years, Golder has provided a broad range of project services, including geotechnical, permitting and environmental, both on land and offshore.
A key component of the project was the development of the first phase of the marine export terminal, which required dredging and management of some 3M m3 of sediment. Building on our long history of working in the area, and on our deep knowledge of the local geohazards including submarine slope stability and seismicity, we worked with the client to develop and implement a multi-phased program to collect sufficient data for their preliminary port design and associated materials management and permitting requirements. We conducted marine geotechnical and sediment quality investigations, biological surveys, and extensive oceanographic and meteorological data collection and modelling over a period of several years.
The presence and distribution of marine clays in the area influenced every aspect of the project. For example: there was the potential risk of a tsunami if submarine landslides were triggered during dredging or disposal; if there were slope failures, there were implications for the generation of turbidity currents disturbing material placed at the disposal location.
The key to the success of the permitting program was the integrated multi-disciplinary Golder team involved on the project, and a common understanding of the overall project objective and complexities. An extensive numerical modelling program was employed to characterize oceanographic and estuarine processes in the area, and combined with evaluation of sediment quality, biological surveys of deep-water habitat using tools like a remotely operated (ROV) underwater camera, and assessment of potential for effects on aquatic resources and uses. Following these well-integrated studies, a location for disposal of dredged sediments near the harbor was selected and approvals were successfully obtained.