| Titre | Detecting the presence of localized ground water inputs into high Arctic lakes |
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| Auteur | Harasyn, M L; Lamoureux, S F; Normandeau, A |
| Source | GeoOttawa 2017, proceedings; 2017 p. 233-234 |
| Image |  |
| Année | 2017 |
| Séries alt. | Ressources naturelles Canada, Contribution externe 20170103 |
| Réunion | GeoOttawa 2017 - 70th Canadian Geotechnical Conference and the 12th Joint CGS/IAH-CNC Groundwater Conference; Ottawa; CA; Octobre 1-4, 2017 |
| Document | livre |
| Lang. | anglais |
| Media | en ligne; numérique |
| Formats | pdf |
| Province | Nunavut |
| Région | Cape Bounty; Melville Island |
| Sujets | écoulement de la nappe d'eau souterraine; pergélisol; hydrogéologie; géologie des dépôts meubles/géomorphologie; Nature et environnement; Sciences et technologie |
| Diffusé | 2017 10 01 |
| Résumé | (disponible en anglais seulement)
This research investigated the presence of ground water seepage within two High Arctic lakes situated in continuous permafrost at Cape Bounty, Melville Island,
Nunavut. Small isolated depressions (21) were identified at the bottom of each lake using 2-meter resolution swath bathymetric data in East and West Lake (unofficial names). It was hypothesized that these depressions could be the sites of ground
water seepage into the lakes, which was tested through the collection of CTD water column casts and bottom water sampling in 2016. Water chemistry and water column data were used as indicators of ground water seepage, and were expected to have
properties similar to the source of the groundwater, generating a change in water chemistry at seepage sites. Water chemistry shows site-specific changes at the bottom of both lakes. Ionic ratios for the northern, deeper sites in both lakes differ
from ratios of the rest of the sample sites, as well as the ambient water column of each lake. These locations are on strike and in the vicinity of the boundary between two major geologic units. Water column properties (temperature, SpC and DO)
showed no measurable change within East Lake, while a localized change within the lower 9 m of the West Lake had increased electrical conductivity and temperature, as well as a corresponding decrease in dissolved oxygen. Despite measured differences
in water column properties between the lakes, bottom water ionic composition is more similar to marine water than to catchment surface runoff or the respective lake water columns. These results suggest that highly localized ground water seepage is
likely occurring in these High Arctic lakes. Potential pathways for ground water flow beneath these lakes have been identified based on knowledge of water source characteristics and permafrost dynamics and likely represent either subpermafrost water
or brines rejected during permafrost growth or sufficiently saline to be mobile as intrapermafrost groundwater. |
| Sommaire | (Résumé en langage clair et simple, non publié)
Le but de ce projet de recherche est de déterminer s'il y a présence d'infiltrations d'eaux souterraines dans deux lacs de l'Arctique situés
dans le pergélisol permanent dans la partie centrale sud de sur le centre-sud de l'île Melville, au Nunavut. Ces deux lacs sont situés à l'Observatoire des bassins versants de Cape Bounty (CBAWO, 75 °N, 109 °O) et ont fait l'objet d'une surveillance
physicochimique de 2003 à 2016. Nos résultats suggèrent que des infiltrations d'eau souterraine hautement localisées se produisent probablement dans ces lacs du Haut-Arctique. |
| GEOSCAN ID | 302738 |
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