Magnitude-frequency characteristics of effective discharge for suspended sediment transport, Fraser River, British Columbia, Canada
✍ Scribed by Henry M. Sichingabula
- Publisher
- John Wiley and Sons
- Year
- 1999
- Tongue
- English
- Weight
- 302 KB
- Volume
- 13
- Category
- Article
- ISSN
- 0885-6087
No coin nor oath required. For personal study only.
✦ Synopsis
This study analyses archival discharge and sediment concentration data (1965±1988), monitored by Water Survey of Canada, to examine suspended sediment transport rates and their relationship to eective discharge (Q e ) based on daily discharge duration curves. Eective discharge was determined as the mid-point of the discharge class transporting the greatest portion of the suspended sediment load (hence class-based Q e ). Results showed that the concept of eective discharge was applicable to the Fraser River basin where the average class-based Q e occurred during 8 . 4% of the study period with individual values ranging from 0 . 03% to 16 . 1%. The durations of eective discharge classes ranged from 0 . 02% to 19 . 6% while the transport of 50% of total sediment loads ranged from 3% to 22% with an average of 14% of the time. Equations for predicting the class-based Q e in the Fraser River basin from bankfull discharge and drainage area are presented. The observed variations among stations in sediment-discharge regimes based on subjectively selected 20 discharge classes, seem to re¯ect the in¯uence of sediment controlling factors such as geology, physiography, catchment size and land use practice in the basin. Future directions of research on applications of the eective discharge concept are explored. As a solution to the problem of lack of an objective method for determining the eective discharge, the eective discharge should be determined from event based assessments of sediment transport (event-based Q e ), avoiding any subjectivity in the selection of number of discharge classes used for its determination. In conclusion, it is proposed that continued use of the conventional method of determining Q e should cease.