Overview of water level, discharge and ice in the St. Lawrence Seaway at Montreal
Notice bibliographique
Résumé
Unlike in most other countries, rivers in Canada freeze during the colder months of the year. Hence, in addition to flooding events in open water, which are a challenge on their own, those involving ice introduce an additional set of issues which are also difficult to foresee and prepare against, given the acknowledged complexity of river ice dynamics. The purpose of this report is to examine the influence of surface ice on water levels in the St. Lawrence River, with the premise that an improved understanding of related phenomena would ultimately increase the reliability of the well-known stage-discharge relationships in winter conditions and provide additional insights into floods induced by ice. Fundamental to any endeavor aimed at monitoring water levels are basic principles in hydrology and hydraulics, including the various field methods used to gather these data – these are summarized. The basis for the relationship between stage and discharge is the Manning formulation. When ice is present, however, that relationship is no longer reliable. Instead, the presence of ice can lead to very high-water levels at relatively low discharge, which is caused by channel constriction by ice keels below the water surface. Lake St. Louis, a river segment along the St. Lawrence Seaway next to Montreal, is the target area for a site-specific analysis presented in this report. Historical stage and discharge data for up to 50 years were downloaded from ECCC’s website – these were generated at two hydrological stations: Pointe-Claire and Lasalle. Indirect evidence of the influence of ice on stage is indicated by the difference in daily water level patterns: they fluctuate more in the winter than in the summer. Discharge, which is derived from water levels, is also more stable in the summer than in the winter (bearing in mind it is considered unreliable for icy conditions). A full-ice cover is associated with low water levels, which may be caused by non-uniform flow, leading to a variation of water depths in the flow direction observed between the two stations. This is consistent with observed discrepancies in water levels at the stations. Additional insights could be obtained with more detailed information about the ice cover and its dynamic behavior, as well as about discharge from the Ottawa River and that resulting from dam operations.
Récupéré en direct depuis OpenAlex et désinversé. Les résumés ne sont pas conservés dans cette base de données : les index inversés représentent 8,6 Go des 9,3 Go de texte de la base, et le serveur dispose de 13 Go libres.
Comment cette classification a été obtenuedéplier
Prédiction machine sur la base complète
Imitation des enseignantsNi prévalence calibrée, ni vérité terrain. Validation humaine à venir. Le volet Gemma est une étiquette directe du modèle pour chaque travail de la base, lue sur la notice réduite au titre. Le volet Codex est un classifieur appris des 10 348 étiquettes directes de Codex et calibré sur les taux pondérés de l'échantillon; les champs sans appui suffisant ne portent aucun appel Codex. Le mode candidate est l'union des deux volets; le consensus est leur intersection. Ces sorties portent le statut machine_predicted_unvalidated et ne sont pas des étiquettes humaines.
Scores du classifieur distillé par catégorie (deux têtes)
| Catégorie | Codex | Gemma |
|---|---|---|
| Métarecherche | 0,000 | 0,000 |
| Méta-épidémiologie (sens strict) | 0,000 | 0,000 |
| Méta-épidémiologie (sens large) | 0,000 | 0,000 |
| Bibliométrie | 0,005 | 0,009 |
| Études des sciences et des technologies | 0,001 | 0,000 |
| Communication savante | 0,001 | 0,000 |
| Science ouverte | 0,001 | 0,001 |
| Intégrité de la recherche | 0,000 | 0,000 |
| Charge utile insuffisante (le modèle a refusé de juger) | 0,010 | 0,001 |
Scores machine (provisoires)
Les deux têtes enseignantes du modèle étudiant, lues sur ce travail. Un score ordonne la base pour la relecture; il n'affirme jamais une catégorie, et le statut de validation accompagne chaque rangée tel quel.
Scores de référence d'un modèle non mature (critères de maturité non atteints, 7 itérations). Un score ordonne; il n'affirme jamais une catégorie.
score_only:v0-immature-baseline · tel quel depuis la passe de notation : score_only signifie que le nombre peut ordonner les travaux, et qu'aucune étiquette de catégorie n'en découleClassification
machine, non validéePrédiction automatique; un appel candidat d’une seule source (Gemma direct ou Codex distillé), pas un consensus.
Le détail, modèle par modèle et score par score, se trouve en fin de page sous « Comment cette classification a été obtenue ».