Determining the Sources of Sediment Delivered by the Fraser River to the Strait of Georgia

Bernhard P-Ehrenbrink, Marine Chemistry & Geochemistry


2014 COI Funded Project


Transport of terrestrial sediment to the coasts is of fundamental importance for the sustainability of deltas and shorelines.  The Fraser River for instance – undammed and without lakes on its main stem to hold back sediment – delivers about 17 million tons of sediment each year to its delta in Vancouver, and the Strait of Georgia.  Here, I propose to expand a new collaboration with fluvial geomorphologists at Simon Fraser University, B.C.  to determine source areas of Fraser River sediment by means of isotope systematics of sedimentary particles.  Preliminary data indicate that sediment source areas change substantially throughout the year.

This study will also illuminate the role fluvial sediments play in the carbon cycle.  The Fraser River delivers carbon in about equal proportions in dissolved and particulate forms.  Our team has studied the dissolved load since 2009 (Voss et al., 2014).  However, the complexity associated with quantifying the particulate flux has thus far prevented us from complementing dissolved with particulate fluxes.  Our new collaboration with SFU scientists offers a unique opportunity to achieve this goal.  I request support to participate in four short trips to carry out depth-specific suspended sediment sampling in the Fraser River during low, medium and high flow conditions across the 2014 freshet.  An NSF proposal is pending that seeks support for the scientific objectives.