Ministry of Environment Environmental Stewardship Division Region 2 – Lower Mainland Ecosystems SectionPrepared by
Bibliographic record
Abstract
Two different dredging techniques in similar channelized stream reaches of the same watershed were compared in a field trial in the lower Fraser Valley, near Chilliwack, British Columbia, during the late summer to early autumn of 2003 and 2004. The objective of this study was to assess the within-season and the one-year post impacts of drainage-channel maintenance on juvenile salmonid habitat. A reach of Marblehill Creek experienced a “hard ” bank-to-bank dredging with little-to-no utilization of fish habitat mitigation measures. The second treatment reach, in Big Ditch, experienced a “softer ” form of dredging where fish habitat structures, in the form of rip-rap rock weirs, were restored as the dredging was undertaken. The key variables used to determine effects through comparison between the treatments included: 1. an assessment of the relative abundance of juvenile fish using minnow trapping; 2. measurements of angular canopy density (ACD) along the stream channels (a proxy measurement for stream-channel shading); 3. an assessment of thalweg-velocity variability; and 4. the calculation of channel-roughness coefficients. The fish-use comparisons support four important conclusions regarding the juvenile salmonid habitat impacts relating to these dredging activities: 1. unmitigated channel dredging had a severe detrimental effect on the within-season relative abundance of over-summer rearing coho salmon (Oncorhynchus kisutch) (up to-94%) and coastal cutthroat trout (O. clarki clarki) (up to-
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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 | 0.001 |
| Science and technology studies | 0.001 | 0.000 |
| Scholarly communication | 0.001 | 0.000 |
| Open science | 0.000 | 0.001 |
| Research integrity | 0.000 | 0.000 |
| Insufficient payload (model declined to judge) | 0.055 | 0.008 |
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".