ABSTRACT

McLaren, P., 2016. The environmental implications of sediment transport in the waters of Prince Rupert, British Columbia, Canada: A comparison between kinematic and dynamic approaches.

A Sediment Trend Analysis (STA®) was performed on 2474 grain-size distributions taken from the Port of Prince Rupert, British Columbia, Canada. The analysis was commissioned by the Lax Kw'alaams First Nations Band because of environmental concerns associated with future large-scale development plans, including a proposed liquefied natural gas (LNG) terminal associated with Flora Bank. Located at the mouth of the Skeena River, Flora Bank has long been considered an important nursery area for juvenile salmon. STA is an empirical technique to determine patterns of net sediment transport, which may provide a qualitative assessment of the possible environmental changes that could be expected following port construction. The patterns of transport revealed that sediments throughout the study area are derived from underlying till which is exposed in areas of strong currents. Flora Bank, a roughly 4 km2 area of intertidal sand, contained the coarsest and most well sorted sand, which was not found elsewhere throughout the study area. Although derived from till, the sand did not form transport pathways from the other sediment types; in addition, pathways could not be determined on the bank itself. It is concluded that the surficial sediments of Flora Bank are a lag derived from underlying glacial deposits caused as coastal processes became active during a lowering sea level that reached its present position about 8000 years ago. They are, therefore, relict sediments held in place by the processes surrounding the bank. This suggests that the design plan for the proposed LNG terminal could disrupt the processes in such a way that sand could be lost from the bank. This finding is contrary to that derived from numerical modeling, which concludes that no environmental harm will be done. Efforts are presently underway for future collaboration in an attempt to resolve the discrepancy and to more accurately understand the risks to Flora Bank.

You do not currently have access to this content.