Bed sediment sources and mixing in the glacierized upper Fraser River watershed, east-central British Columbia

2004 ◽  
Vol 29 (5) ◽  
pp. 533-552 ◽  
Author(s):  
Randy W. Dirszowsky
1997 ◽  
Vol 34 (11) ◽  
pp. 1509-1520 ◽  
Author(s):  
David H. Huntley ◽  
Bruce E. Broster

Late Wisconsinan Fraser Glaciation retreat-phase deposits and landforms in the east-central Taseko Lakes area, British Columbia, are used to demonstrate a four-phase model of deglaciation. During phase I, at the onset of ice retreat, the Cordilleran Ice Sheet occupied much of the study area, blocking southward drainage of Fraser River. Phase II was marked by the deglaciation of uplands and plateaux. Meltwater drainage patterns were controlled by stagnating glaciers confined to valleys. Phase III commenced as remnant ice in the Fraser Valley downwasted to between 850 and 760 m elevation. At this time, interlobate glacial lakes formed in hanging valleys east of Fraser River. Drainage of glacial lakes occurred subglacially, and was accompanied by disintegration of remnant ice and an increase in mass movements in valleys. These events were followed by decreased sedimentation rates, reflecting lower meltwater volumes and exhaustion of unstable glacial debris during phase IV. Postglaciation valley fill was subject to fluvial degradation and terracing as modern drainage patterns became established.


1989 ◽  
Vol 26 (7) ◽  
pp. 1440-1452 ◽  
Author(s):  
R. A. Kostaschuk ◽  
M. A. Church ◽  
J. L. Luternauer

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.


1998 ◽  
Vol 33 (4) ◽  
pp. 519-550 ◽  
Author(s):  
Paul A. Zandbergen ◽  
Ken J. Hall

Abstract The use of indices in ecosystem management is attractive because it allows for the representation of a complex set of information on ecosystem variables in a simple fashion. Recently the British Columbia Ministry of Environment, Lands and Parks developed the British Columbia Water Quality Index (BCWQI). As this index is currently being considered as the basis for other provincial indices and a national water quality index, the character of the BCWQI needs to be carefully considered. This study evaluates the performance of the BCWQI and assesses how useful and appropriate it is as a management tool at the watershed level. For this purpose the index is used to express the results of two sampling programs, one by the British Columbia Ministry of Environment, Lands and Parks, and the other by the Westwater Research Centre, of two relatively small watersheds in the Greater Vancouver area: the Brunette River watershed, heavily impacted by urbanization, and the Salmon River watershed on the urban-rural fringe. For both watersheds the intended use is the protection of aquatic life and only those water quality objectives are considered. The results indicate that the BCWQI is extremely sensitive to sampling design and highly dependent on the specific application of water quality objectives. A comparison is made with another type of index in widespread use in North America: the National Sanitation Foundation Water Quality Index (NSFWQI). This index appears promising for stream stewardship groups because of its simplicity and ease of use. For watershed managers, an alternative to the BCWQI is suggested, based on exceedance factors for individual objectives. This Simple Water Quality Index (SWQI) recognizes the importance of objectives that are specific to a particular water body, but overcomes some of the limitations of the BCWQI. A presentation format is suggested for objective exceedance factors, with a clear indication of exactly which objectives were included — without this, the final numerical index value is meaningless. This study suggests that the BCWQI in its current form has serious limitations for comparing water bodies and for establishing management priorities. If local watershed managers use the BCWQI in guiding efforts to protect aquatic resources, they should consider these limitations carefully.


2002 ◽  
Vol 263 (1-4) ◽  
pp. 230-244 ◽  
Author(s):  
John Morrison ◽  
Michael C Quick ◽  
Michael G.G Foreman

1980 ◽  
Vol 58 (4) ◽  
pp. 623-625 ◽  
Author(s):  
Terry D. Beacham

A 2-year livetrapping study on Townsend's vole (Microtus townsendii) on Reifel Island in the Fraser River delta in British Columbia, Canada, showed that there was an early stop to summer breeding in the peak phase summer compared with the increasing phase summer. Selective dispersal and death of early-maturing voles may account for this result. A delay occurred in the onset of breeding in the decline phase. Voles in peak density populations had the highest median weights at sexual maturity, and males matured at heavier weights than did females.


2004 ◽  
Vol 133 (6) ◽  
pp. 1396-1412 ◽  
Author(s):  
R. J. Beamish ◽  
J. T. Schnute ◽  
A. J. Cass ◽  
C. M. Neville ◽  
R. M. Sweeting

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