River discharge and tidal controls on salt-wedge position and implications for channel shoaling: Fraser River, British Columbia

Abstract

Salinity and current surveys in the Main Channel of the Fraser River estuary, British Columbia, show that a well-defined salt-wedge intrusion migrates along the channel. Bivariate statistical analyses reveal that when discharge is nearly constant, the position of the salt-wedge is controlled by tidal height. Multivariate analyses of data with large ranges in discharge and tidal height indicate that intrusion location is a function of both discharge and tides. Multiple regression models provide predictive relations for salt-wedge position. Application of a regression model indicates that channel shoaling at the mouth of the river is related to the low-tide position of the salt-wedge. Key words: Fraser River estuary, salt-wedge position, channel shoaling.