On the validity of the British Columbia Forest Practices Code guidelines for stream culvert discharge design
Bibliographic record
Abstract
In the stream culvert discharge design guidelines of the Forest Practices Code (FPC) of British Columbia (BC), the 100-year instantaneous flood (Q100) is assumed to be three times as large as the mean annual flood (Q2) regardless of basin characteristics and location in the province. A regional linear moment analysis of annual maximum flows is used to demonstrate that this assumption is invalid and that Q100/Q2ratios vary substantially with basin area and climate. For the snowmelt-dominated peak flows in the Columbia and southern Rocky Mountains, Q100/Q2decreases slightly with increasing drainage area, from 2.3 (1 km2) to 1.9 (100 km2). For the flood peaks generated by rainfall and rain on snow in coastal BC, this range is 3.12.6. In the semi-arid Interior Plateau region, variability in Q100/Q2ratios is most dramatic. For a 10-km2basin, the calculated Q100/Q2ratio of 4.9 is 1.6 times the assumed factor of 3, while for a 1-km2basin Q100/Q2is 7.5 or 2.5 times this factor. Underestimating Q100/Q2may lead to underdesign and early failure of road culverts, and therefore, current FPC guidelines for estimating the 100-year instantaneous flood may have serious adverse economic and environmental consequences in small Interior Plateau watersheds.
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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 | 0.010 | 0.063 |
| Meta-epidemiology (narrow) | 0.000 | 0.000 |
| Meta-epidemiology (broad) | 0.000 | 0.000 |
| Bibliometrics | 0.002 | 0.005 |
| Science and technology studies | 0.004 | 0.002 |
| Scholarly communication | 0.006 | 0.001 |
| Open science | 0.002 | 0.001 |
| Research integrity | 0.001 | 0.002 |
| Insufficient payload (model declined to judge) | 0.005 | 0.001 |
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".