Notice bibliographique
Résumé
Removal of low-head and mill pond dams throughout North America has garnered considerable attention over the past twenty years. Dam removal along watercourses is frequently being considered to address private and public liability regarding the failure of old and/or abandoned dams, removal of aquatic migration barriers and, to improve nutrient spiraling to enhance both downstream and upstream ecological diversity. A significant number of studies have been conducted over the past 50 years regarding the ecological impacts of dams, rates of reservoir sedimentation and, down stream erosion. Further, several more studies have examined and employed strategies for the decommissioning of dams, limiting downstream sediment deposition and improving fish migration. However, few studies have examined the upstream impacts of dam decommissioning beyond the backwater limits of reservoirs. This study examines the upstream effects of low-head dam decommissioning on channel morphology using the analog of existing failed dams by natural processes. The most drastic method of dam decommissioning is the "blow and go" approach, whereby a dam is removed and the watercourse is simply allowed to reassume a stable morphology (often assumed to be the pre-dam morphology). A series of low-head and mill pond dams were studied in southern Ontario which failed between 6 – 45 years before present and at locations where no upstream channel mitigation has taken place to provide an analog to the "blow and go" methodology. In each study reach, longitudinal profiles and cross-sectional field surveys were conducted from below the dam faces for several meander wave lengths upstream of each reservoir backwater limits. Numerical models were developed for the historical dam operational and current hydraulic conditions. Pavement samples were collected from riffles and headcuts within and above the reservoir regions of each reach and tractive force and sediment transport analyses conducted. Findings demonstrate that erosional disturbances typically in the form of headcuts and lateral migration are frequently observed at considerable distances upstream of reservoir limits. Depending upon the upstream bedload grain size distribution, the rate of channel armouring and dam height (i.e. localized friction slope), channel disturbances may continue for several decades and continue to degrade a given watercourse for several kilometers upstream of a reservoir. Findings further support the need to consider upstream grade-control and floodplain re-connectivity as part of such restoration initiatives to minimize degradational impacts, down stream sedimentation and to stabilize aquatic and riparian habitat.
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 distillée sur la base complète
Imitation des enseignantsNi prévalence calibrée, ni vérité terrain. Validation humaine à venir. Apprise à partir de 10 348 étiquettes directes de Codex et de 10 348 étiquettes directes de Gemma. Le mode candidate est l'union des têtes enseignantes seuillées; le consensus est leur intersection. Ces sorties portent le statut machine_predicted_unvalidated et ne sont ni des étiquettes humaines ni des étiquettes directes de modèles de pointe.
Scores Codex et Gemma par catégorie
| 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 | 0,000 | 0,000 |
| Études des sciences et des technologies | 0,000 | 0,001 |
| Communication savante | 0,000 | 0,000 |
| Science ouverte | 0,000 | 0,000 |
| Intégrité de la recherche | 0,000 | 0,000 |
| Charge utile insuffisante (le modèle a refusé de juger) | 0,009 | 0,002 |
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; les deux têtes enseignantes s’accordent sur ce qui est montré ici.
Le détail, modèle par modèle et score par score, se trouve en fin de page sous « Comment cette classification a été obtenue ».