Bedforms, bed material, and bedload transport in a salt-wedge estuary: Fraser River, British Columbia

1989 ◽  
Vol 26 (7) ◽  
pp. 1440-1452 ◽  
Author(s):  
R. A. Kostaschuk ◽  
M. A. Church ◽  
J. L. Luternauer
Keyword(s):  
British Columbia ◽  
River Discharge ◽  
Bedload Transport ◽  
Fraser River ◽  
Seasonal Fluctuations ◽  
Salt Wedge ◽  
Migration Rates ◽  
Material Load ◽  
Bed Material

The lower main channel of the Fraser River, British Columbia, is a sand-bed, salt-wedge estuary in which variations in velocity, discharge, and bedform characteristics are contolled by river discharge and the tides. Bed-material composition remains consistent over the discharge season and in the long term. Changes in bedform height and length follow but lag behind seasonal fluctuations in river discharge. Migration rates of bedforms respond more directly to river discharge and tidal fall than do height and length. Bedform characteristics were utilized to estimate bedload transport in the estuary, and a strong, direct, but very sensitive relationship was found between bed load and river discharge. Annual bedload transport in the estuary is estimated to be of the order of 0.35 Mt in 1986. Bedload transport in the estuary appears to be higher than in reaches upstream, possibly because of an increase in sediment movement along the bed to compensate for a reduction in suspended bed-material load produced by tidal slack water and the salt wedge.

The influence of population dynamics and environmental conditions on pink salmon (Oncorhynchus gorbuscha) recolonization after barrier removal in the Fraser River, British Columbia, Canada

2012 ◽  
Vol 69 (5) ◽  
pp. 970-982 ◽  
Author(s):  
G.R. Pess ◽  
R. Hilborn ◽  
K. Kloehn ◽  
T.P. Quinn
Keyword(s):  
British Columbia ◽  
Abiotic Factors ◽  
Pink Salmon ◽  
River System ◽  
Oncorhynchus Gorbuscha ◽  
Source Population ◽  
Fraser River ◽  
Extrinsic Factors ◽  
Barrier Removal

When barriers are removed, what biotic and abiotic factors determine how fish populations will colonize newly available habitats? We used counts of adult pink salmon ( Oncorhywnchus gorbuscha ) from 1947 to 1987 in 66 streams of the Fraser River system, British Columbia, Canada, to determine when colonizing pink salmon populations became self-sustaining after a long-term migration blockage at Hell’s Gate (river kilometre 209) was reduced. The abundance of salmon in available habitats were largely controlled by extrinsic factors such as an initially large source population, high intrinsic growth rates linked to favorable climate-driven conditions, a constant supply of dispersers, and large amounts of newly available habitat. Temporal variation in flows at Hell’s Gate also affected recolonization success. Self-sustaining populations were developed within years of barrier removal and have continued to help expand the overall population of Fraser River pink salmon. However, pink salmon were considerably more abundant in the early 1900s than in the 1980s (∼48 million vs. ∼2.7 million), and the majority of spawning shifted from the historic areas above Hell’s Gate prior to the rockslide to below Hell’s Gate in the lower Fraser River after the long-term blockage was reduced, so the system has not returned to the former abundance and distribution patterns.

Effects of a fluctuation in Fraser River discharge of primary production in the central Strait of Georgia, British Columbia, Canada

1997 ◽  
Vol 54 (5) ◽  
pp. 1015-1024 ◽  
Author(s):  
K Yin ◽  
P J Harrison ◽  
R J Beamish
Keyword(s):  
British Columbia ◽  
Primary Production ◽  
River Discharge ◽  
Euphotic Zone ◽  
Early Summer ◽  
Phytoplankton Production ◽  
Fraser River ◽  
Strait Of Georgia ◽  
Chl A ◽  
First Time

High-resolution vertical profiles of salinity, temperature, fluorescence, and nutrients (NO3 and SiO4) were taken along a transect in the central Strait of Georgia, British Columbia. The Fraser River discharge increased rapidly over 4 days and then decreased over the following 3 days (June 16-19, 1991). The thickness and extent of the estuarine plume increased as a response to the increased river discharge. As the estuarine plume flowed seaward, the nutricline (NO3) became shallower and broader, resulting in an increase in NO3 in the euphotic zone. Entrainment of NO3 may explain the increase in NO3 in the surface layer, and the amount of NO3 entrained was estimated to be 5-10 times higher than river-borne NO3. The utilization of entrained nutrients increased Chl a concentrations and primary production to levels comparable with spring bloom values. Our results clearly demonstrated for the first time that entrainment of nutrients and phytoplankton production in the central Strait of Georgia are closely coupled to fluctuations in the Fraser River discharge as the estuarine plume moves seaward. The timing and magnitude of the May-June freshet could control the entrainment of nutrients and thus maintain high primary productivity in late spring - early summer.

Sediment transport by tidal currents and implications for slope stability: Fraser River delta, British Columbia

1995 ◽  
Vol 32 (7) ◽  
pp. 852-859 ◽  
Author(s):  
R. A. Kostaschuk ◽  
J. L. Luternauer ◽  
J. V. Barrie ◽  
P. H. Leblond ◽  
L. Werth Von Deichmann
Keyword(s):  
Sediment Transport ◽  
Slope Failure ◽  
Tidal Currents ◽  
River Delta ◽  
Fraser River ◽  
Dune Field ◽  
Fraser River Delta ◽  
Material Load ◽  
And Migration ◽  
Bed Material

Tidal currents on the sandy, southern slope of Fraser River delta have generated dunes with heights of 0.5–3.5 m and lengths of 11–108 m. Dune geometry and migration measurements indicate net sediment transport to the northwest in the direction of flood tidal currents. Two current meters moored in the dune field showed greater frequencies of occurrence and higher mean current speeds in the flood direction compared with the ebb. Predictions from two bed-material load models indicate sediment transport is overwhelmingly dominated by flood currents. There is no obvious source of sand to replace sediment transported in the dune field, suggesting net erosion of the surface. A previous analysis of bathymetric data also shows recent erosion of the lower slope and overall slope steepening. These patterns of erosion could lead to slope failure and damage to coastal structures.

Migration of viscous non-aqueous phase liquids (NAPLs) in alluvium, Fraser River lowlands, British Columbia

2006 ◽  
Vol 43 (7) ◽  
pp. 694-703 ◽  
Author(s):  
Richard E Jackson ◽  
Varadarajan Dwarakanath ◽  
John E Ewing ◽  
John Avis
Keyword(s):  
British Columbia ◽  
Aqueous Phase ◽  
Coal Tar ◽  
Chlorinated Solvents ◽  
Creeping Flow ◽  
Fraser River ◽  
Manufactured Gas Plants ◽  
A Site ◽  
Gas Plants

Coal tar, creosote, and similar viscous non-aqueous phase liquids (NAPLs) behave in alluvial soils in a manner significantly different from that of less viscous NAPLs, such as gasoline and chlorinated solvents. Their unique behavior is due to the interaction of their physical–chemical parameters: a density often greater than water, a viscosity significantly greater than water, and an interfacial tension that yields a positive initial spreading coefficient at air–water–NAPL interfaces. This results in slow, creeping flow that causes long-term contamination at former manufactured gas plants and wood-preserving sites and of their adjacent surface waters. Multiphase simulations of this creeping flow are shown for a site along the lower Fraser River near Vancouver, British Columbia, and the long-term consequences of the migration of viscous NAPLs in alluvium are discussed from the perspective of site characterization and brownfields redevelopment.Key words: creosote, coal tar, multiphase simulation, brownfields, NAPL.

scholarly journals Paleohydrological context for recent floods and droughts in the Fraser River Basin, British Columbia, Canada

2021 ◽  
Author(s):  
Becky L. Brice ◽  
Bethany Lynn Coulthard ◽  
Inga K. Homfeld ◽  
Laura Dye ◽  
Kevin J. Anchukaitis
Keyword(s):  
British Columbia ◽  
River Basin ◽  
Fraser River ◽  
Proxy Records ◽  
Target Management ◽  
Floods And Droughts ◽  
High Flood ◽  
Cultural Ecological ◽  
Observational Record

Abstract The recent intensification of floods and droughts in the Fraser River Basin of British Columbia has had profound cultural, ecological, and economic impacts that are expected to be exacerbated further by anthropogenic climate change. In part due to short instrumental runoff records, the long-term stationarity of hydroclimatic extremes in this major North American watershed remains poorly understood, highlighting the need to use high-resolution paleoenvironmental proxies to inform on past streamflow. Here we use a network of tree-ring proxy records to develop 11 subbasin-scale, complementary flood- and drought-season reconstructions, the first of their kind. The reconstructions explicitly target management-relevant flood and drought seasons within each basin, and are examined in tandem to provide an expanded assessment of extreme events across the Fraser River Basin with immediate implications for water management. We find that past high flood-season flows have been of greater magnitude and occurred in more consecutive years than during the observational record alone. Early 20th century low flows in the drought season were especially severe in both duration and magnitude in some subbasins relative to recent dry periods. Our Fraser subbasin-scale reconstructions provide long-term benchmarks for the natural flood and drought variability prior to anthropogenic forcing. These reconstructions demonstrate that the instrumental streamflow records upon which current management is based likely underestimate the full natural magnitude, duration, and frequency of extreme seasonal flows in the Fraser River Basin, as well as the potential severity of future anthropogenically forced events.

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

1990 ◽  
Vol 17 (3) ◽  
pp. 452-459 ◽  
Author(s):  
R. A. Kostaschuk ◽  
L. A. Atwood
Keyword(s):  
British Columbia ◽  
Regression Models ◽  
Multivariate Analyses ◽  
River Estuary ◽  
Main Channel ◽  
Tidal Height ◽  
Fraser River ◽  
Salt Wedge ◽  
Multiple Regression Models ◽  
Predictive Relations

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.

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