The Influence of a Salt Wedge and Tidal Flow Dynamics on Contaminant Pathways in the Fraser River Estuary, British Columbia

Abstract

The Fraser River Estuary is one of Canada’s most productive and valuable wildlife habitats. The estuary supports the largest population of wintering wildfowl in Canada and is used by about half the birds migrating along the Pacific flyway. The river is renowned for its salmon runs; the five species of salmon that live in or pass through the estuary produce the largest natural salmon run in the world. The value of the commercial and recreational fishery supported by the Fraser is estimated at $90 million. At the same time, the estuary is home to more than 1.25 million people and is intensively used for heavy industry and resource-related enterprises. In an attempt to balance the natural environment with ever increasing industrial, commercial, recreational and residential pressures, an inter-governmental, inter-agency program called the Fraser River Estuary Management Program (FREMP) was established. One of the activities under FREMP is the development of a water quality plan for the estuary which involves the setting of site-specific water quality objectives and the establishment of a monitoring program. Although much work on contaminant identification and distribution has been completed, the development of site-specific objectives and the establishment of the monitoring program has been delayed, partially because of uncertainty with respect to the complex mixing processes in the estuary and their impact on contaminant dynamics.