Stream Modifications to Enhance Fish Habitat in Arctic Headwater Systems
Notice bibliographique
Résumé
Disruptions to Canada’s pristine northern regions have been steadily increasing due to industrial activities. Many of these impacts lead to destruction or harmful alteration of aquatic ecosystems. Recently, efforts have been made to reduce and offset aquatic habitat impacts through habitat compensation projects. This thesis investigated two habitat compensation projects in the Barrenlands region of Canada to explore the hydraulic responses to stream modifications and determine the efficacy of constructing these works in remote locations with a limited understanding of site characteristics. First, an investigation was conducted to explore various stream modification efforts to enhance ecosystem connectivity of an isolated system of three small lakes by enhancing system connectivity. The lakes’ ephemeral outlet streams were modified, intending to create conditions favorable for fish passage and thereby promote movement among the lakes and the large lake into which they drain. Variation of lake levels and duration, variability, and depth of stream flow indicated that outlet geometry and lake catchment area should be important considerations when enhancing connectivity for fish in ephemeral systems. A narrow, rectangular outlet cross-section was deemed effective for increasing flow depth while decreasing discharge, resulting in increased duration of flows. Catchment area was an effective indicator of a headwater lake’s potential response to connectivity enhancements. Smaller catchments may provide inadequate runoff to sustain minimum storage requirements for enhanced connectivity. Second, we investigated efforts to enhance spawning habitat and connectivity to a headwater stream. An on-site, field engineering approach at the time of construction was developed for design of these modifications. This approach addressed challenges associated with remote construction and limited information on site characteristics, focusing on communicating to the construction crew the intent of the designs, rather than a detailed design, to facilitate modification and optimization of structures when confronted with unforeseen challenges. Primary design considerations included (1) controlling flows in periods of high and low discharges; (2) minimizing drop heights; (3) improving flow variability for enhanced stream habitat; and (4) salvaging and incorporating vegetation disturbed from construction activities into riparian and in-stream habitat structures. Preliminary observations showed suitable depths for fish passage were present over the entire stream during the study period indicating discharges were controlled effectively at all stream gradients. These findings should advance the knowledge of headwater system hydraulics in the Barrenlands and assist in designing future fish habitat compensation projects on similar Arctic systems.
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 | 0,000 |
| 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) | 0,001 | 0,000 |
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 tête enseignante, 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 ».