Morphodynamics of an extended bar complex, Fraser River, British Columbia
Bibliographic record
Abstract
ABSTRACT We investigate large‐scale morphologic changes over a 65‐year period in a major sedimentation zone within the 50‐km long wandering gravel‐bed reach of lower Fraser River, British Columbia. This reach remains in a relatively pristine state compared with many major rivers in populated regions even though various forms of human interference have occurred over the past century to mitigate flooding and erosion concerns. A template of channel evolutionary development is identified, consisting of extended periods of orderly accretion of unit bars by deposition of gravel sheets, controlled by the major riffles in the river. When this process constricts channel conveyance an avulsion occurs and the major bar complexes are reorganized. The recognition of fairly predictable short‐term behavior can potentially aid the development of models of sediment transport and channel evolution. Accordingly, results of the detailed descriptive analysis are compared with a GIS‐based probabilistic approach developed from transition‐state analysis. This reveals that the river has a far stronger tendency to retain its existing morphology than to change its form within a roughly decennial time scale – regardless of the magnitude of intervening flows – but that this tendency gradually declines over time as major bar and island complexes are re‐worked by sediment exchange. The timescale for major bar development appears to be of the order 30 years, while complete sediment exchange occurs within a century. Copyright © 2012 John Wiley & Sons, Ltd.
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How this classification was reachedexpand
Full frame machine prediction
Teacher imitationNot calibrated prevalence, not ground truth. Human validation pending. The Gemma side is a direct model label for every work in the frame, read from the title-only record. The Codex side is a classifier learned from the 10,348 direct Codex labels and calibrated to design-weighted sample rates; fields without enough sample support carry no Codex call. Candidate is the union of the two sides; consensus is their intersection. These outputs are machine_predicted_unvalidated and are not human labels.
Distilled classifier scores by category (both heads)
| Category | Codex | Gemma |
|---|---|---|
| Metaresearch | 0.000 | 0.001 |
| Meta-epidemiology (narrow) | 0.000 | 0.000 |
| Meta-epidemiology (broad) | 0.000 | 0.000 |
| Bibliometrics | 0.001 | 0.002 |
| Science and technology studies | 0.002 | 0.001 |
| Scholarly communication | 0.001 | 0.000 |
| Open science | 0.001 | 0.001 |
| Research integrity | 0.000 | 0.000 |
| Insufficient payload (model declined to judge) | 0.002 | 0.000 |
Machine scores (provisional)
The two teacher heads of the student model, read on this work. A score orders the frame for review; it never asserts a category, and the validation status ships verbatim with every row.
Baseline scores from an immature model (maturity gate not passed, 7 training rounds). Scores rank; they never assert a category.
score_only:v0-immature-baseline · verbatim from the scoring run: score_only means the number may rank works, and no category label ships from itClassification
machine, unvalidatedMachine predicted; a candidate call from one source (direct Gemma or distilled Codex), not a consensus.
How this classification was reached, model by model and score by score, is at the end of the page under "How this classification was reached".