NWT RESEARCH DATABASE

Regions: Dehcho Region

Tags: physical sciences, hydrology, glaciology, environmental change, glacial history, waterflow monitoring, ice retreat

Objective(s): The objectives of this research are to document the glaciers in the Ragged Range, how they have changed in the past and what their role is presently in providing meltwater for the upper reaches of the South Nahanni River and the Flat River.

Project Description: The objectives of this research are to document the glaciers in the Ragged Range, how they have changed in the past and what their role is presently in providing meltwater for the upper reaches of the South Nahanni River and the Flat River. Glaciers nourish streams and groundwater when other sources are absent or in decline (e.g., snowmelt, precipitation). They are most important late in the summer season, when snowcover is largely absent and in association with warm, dry weather. Glaciers also provide eco-system services for species that are highly adapted to cold water temperatures, and stable water levels for reproduction, rearing and migration during warm, dry climate episodes. Extreme flows can also be produced where the presence of glaciers augments river flow during protracted rain on ice events. These higher flows can create beneficial refugia but also may have negative impacts on sedimentation rates and the stability of the river course. The researchers will also work towards determining the future evolution and role of the glaciers in providing flow by employing a hydrological model that will predict streamflow under prescribed glacier cover and climate conditions. Measurements of glacier change and speed are conducted with Differential Global Positioning System (DGPS) receivers, with a base station located over a temporary benchmark located over suitably stable terrain. Snow fall accumulation measurements are conducted by probing and digging snow pits on the glacier (measuring snow stratigraphy and snow density) with hand instruments. Ice melt measurements are conducted by measuring poles which are temporarily placed in the ice using a hand-operated auger. Important meteorological data will be collected using a temporarily located automatic weather station. Transportation to the site is via helicopter originating from Fort Simpson. Once on site, the research team will move around on foot and ski. In general, 2-3 people will visit the glacier twice each year in spring and late summer. The first visit is to measure how the glacier is being nourished and the second visit is to measure how much melt has occurred and how much the glacier surface and its edges have moved. During the second visit, the location of evidence describing previous glacier positions will be located and documented. This includes making DGPS measurements of the location of end moraine and recession moraine complexes as well as site where lichen growth-curve data are being collected. During 1 day in August of 2007, the researchers will have a survey aircraft overhead (c. 6000 feet AGL) for approximately 2-3 hours conducting terrain mapping. The researchers’ primary portal for communicating their findings to individuals and communities of the NWT will be through Parks Canada and their interests in characterizing the Greater Ecosystem Area outside of the Nahanni National Park and Reserve boundaries. Databases and reports, including those in the popular and peer-reviewed literature will be made available to the community and all stakeholders. They will also maintain a web presence where their methods and findings will be detailed, including periodic updates with tabular data, maps, satellite imagery and photography. Outreach materials have been prepared for educational purposes in regards to the occurrence of glaciers in the Ragged Ranges and their role in producing rivers flow when other sources are in decline or absent - particularly for the upper reaches of the South Nahanni River above Virginia Falls. The research is in-part focused towards providing statements of eco-system value and services provided by glaciers and related river flows. This information will be used in consideration of the evolution of the Greater Ecosystem Area surrounding Nahanni National Park and Reserve. As a World Heritage Site, improved knowledge of the hydrology of this river would enhance its appreciation from both a services to ecosystem and tourism point of view. Fieldwork will be conducted from August 17 to 24, 2007at the glaciers and their forelands above the Brintnell and Bologna Creeks, Glacier Lake and, in particular, the Brintnell-Bolgna Icefield (62 deg 5' 55" N ; 127 deg 58' 10" W).