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Sediment transport along lower Fraser River: 1. Measurements and hydraulic computations
Author(s) -
McLean David G.,
Church Michael,
Tassone Bruno
Publication year - 1999
Publication title -
water resources research
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.863
H-Index - 217
eISSN - 1944-7973
pISSN - 0043-1397
DOI - 10.1029/1999wr900101
Subject(s) - bed load , suspended load , hydrology (agriculture) , sediment , sediment transport , geology , sedimentary budget , river bed , bedform , geotechnical engineering , environmental science , geomorphology
A comprehensive program of sediment transport measurements was conducted along lower Fraser River, British Columbia, between 1966 and 1986. The data yield a detailed sediment budget. Annual total suspended loads at three stations are virtually identical, averaging 17 × 10 6 tonnes/year (t yr −1 ). The suspended sand load is about 5.5 × 10 6 t yr −1 , about one third of the total. In the gravel bed reach of the river the sand behaves as wash load. Significant transport of gravel begins at Agassiz at a discharge of about 5000 m 3 s −1 . The annual gravel transport was estimated to be about 0.23 × 10 6 t yr −1 , only 1% of the total load. All of this material is deposited in the reach upstream of Mission. At Mission, sands finer than 0.177 mm make up more than 50% of the suspended sand load but are virtually absent from the sand bed. Therefore a portion of the sand load at Mission is wash load. The total bed material load here was estimated to be 3.0 × 10 6 t yr −1 , about 18% of the total sediment load. Virtually all of the bed material load was transported in intermittent suspension near the bed, less than 5% occurring as bed load. In the long term the suspended sand load upstream is approximately equal to the total sand load at Mission. However, within individual years some of the sand is stored within the reach temporarily and then reentrained later.