Glacial floods and mass movements of ice, rock or debris are a significant hazard in many populated mountainous regions, often with devastating impacts upon human settlements and infrastructure. In response to atmospheric warming, glacial retreat and permafrost thaw are expected to alter high mountain geomorphic processes, and related instabilities. In the Aoraki/Mount Cook region of New Zealand's Southern Alps, a first investigation of geomorphic hazards associated with glacial change is undertaken and is based primarily on the use of remote sensing and Geographic Information Systems (GIS) for mapping, modelling, and analysing related processes and terrain. Following a comprehensive review of available techniques, remote sensing methods involving the use Advanced Spaceborne Thermal Emission and Radiometer (ASTER) imagery were applied to map glacial ice, lakes and debris accumulations in the Aoraki/Mount Cook region. Glacial lakes were mapped from two separate classification techniques using visible near infrared wavelengths, capturing highly turbid and clearer water bodies. Large volume (10⁶– 10⁸ m³) proglacial lakes have developed rapidly over recent decades, with an overall 20 % increase in lake area recorded between 2002 and 2006, increasing the potential for large mass movement impacts and flooding from displaced water. Where significant long-term glacial recession has occurred, steep moraines have been exposed, and large talus slopes occupy formerly glaciated slopes at higher elevations. At the regional-scale, these potential source areas for debris instabilities were distinguished from surrounding bedrock slopes based on image texture variance. For debris and ice covered slopes, potentially unstable situations were classified using critical slope thresholds established from international studies. GIS-based flow routing was used to explore possible intersections between zones of human use and mass movement or flood events, assuming worst-case, probable maximum runout distances. Where glacial lakes are dammed by steep moraine or outwash gravel, primarily in cirque basins east of the Main Divide, modelled debris flows initiated by potential flood events did not reach any infrastructure. Other potential peri- and para-glacial debris flows from steep moraines or talus slopes can reach main roads and buildings. The direct hazard from ice avalanches is restricted to backcountry huts and walking tracks, but impacts into large glacial lakes are possible, and could produce a far reaching hazard, with modelled clear water flood-waves capable of reaching village infrastructure and main roads both east and west of the Main Divide. A numerical modelling approach for simulating large bedrock failures has been introduced, and offers potential with which to examine possible lake impacts and related scenarios. Over 500 bedrock slope failures were analysed within a GIS inventory, revealing distinct patterns in geological and topographic distribution. Rock avalanches have occurred most frequently from greywacke slopes about and east of the Main Divide, particularly from slopes steeper than 50°, and appear the only large-magnitude failure mechanism above 2500 m. In the schist terrain west of the Main Divide, and at lower elevations, other failure types predominate. The prehistoric distribution of all failure types suggests a preference for slopes facing west to northwest, and is likely to be strongly influenced by earthquake generated failures. Over the past 100 years, seismicity has not been a factor, and the most failures have been as rock avalanches from slopes facing east to southeast, particularly evident from the glaciated, and potentially permafrost affected hangingwall of the Main Divide Fault Zone. An initial estimate of permafrost distribution based on topo-climatic relationships and calibrated locally using mean annual air temperature suggested permafrost may extend down to elevations of 3000 m on sunny slopes, and as low as 2200 m on shaded slopes near the Main Divide. A network of 15 near-surface rock temperature sensors was installed on steep rock walls, revealing marginal permafrost conditions (approaching 0 °C) extending over a much larger elevation range, occurring even where air temperature is likely to remain positive, owing to extreme topographic shading. From 19 rock failures observed over the past 100 years, 13 detachment zones were located on slopes characterized by marginal permafrost conditions, including a sequence of 4 failures that occurred during summer 2007/08, in which modelled bedrock temperatures near the base of the detachments were in the range of 1.4 to +2.5 °C. Ongoing monitoring of glacial and permafrost conditions in the Aoraki/Mount Cook region is encouraged, with more than 45 km2 of extremely steep slopes (>50°) currently ice covered or above modelled permafrost elevation limits. Approaches towards modelling and analysing glacial hazards in this region are considered to be most applicable within other remote mountain regions, where seismicity and steep topography combine with possible destabilizing influences of glacial recession and permafrost degradation.

Permafrost temperatures were measured by the Geological Survey of Canada (GSC) in 1977-1981 at boreholes along a proposed pipeline route in the southern Yukon. Analysis of climate station records indicate that mean annual air temperatures in the region have since increased by 0.5-1.0˚C. Renewed interest in the pipeline and the need to develop adaptation strategies for existing highway infrastructure have meant that information on permafrost and geotechnical conditions must be updated. To accomplish this goal, a total of eight GSC boreholes ranging in depth from 5-9 m were located, unblocked of ice and instrumented with thermistor cables and data-loggers to permit renewed ground temperature monitoring. Manual temperature measurements were also taken at four other shallow boreholes. Electrical resistivity tomography (ERT) surveys were conducted at each site. MAGTs below 1 m at permafrost sites in the study area range from -0.2˚C to -1.5˚C with permafrost depths greater than 25 m. The permafrost at the study sites can be classified as sporadic discontinuous and extensive discontinuous. Ground temperatures indicate that permafrost can persist under warmer climatic conditions as long as it remains protected by its ecosystem properties. Thermal monitoring for 2011-2012 shows an average increase of 0.5-1.0˚C when compared to the original 1978-1981 ground temperatures. This slow rate of ground warming is mainly attributed to a combination of limited climate change, especially in the south of the study area, ground temperatures close to 0˚C, and the possible disturbance of sites from the removal of vegetation prior to the original measurements being made. ERT surveys conducted at most borehole sites show deeper thaw or taliks where the cleared cut-line used for geophysical work in the 1970s is crossed. These results indicate the impacts of climate change and environmental change in the study area over the past three decades. They appear to match the relatively slow rates of ground warming observed elsewhere in northern Canada where permafrost temperatures are close to 0˚C and where warming also requires changes in latent heat due to internal thaw. TTOP equilibrium modelling suggests that if climate change is responsible for the ground warming, most of the change can be attributed to the step-like MAAT increase that occurred between 1975-1976.

This study investigates the runoff process and groundwater behavior in a subarctic watershed called Wolf Creek Research Basin, in Whitehorse, Yukon Territory, Canada. This basin is underlain by discontinuous permafrost that is typical of high latitude watersheds. Goundwater supports the stream flow year round and dominated the hydrology in most of the study period as baseflow. The baseflow was concentrated in dissolved ions. However, the baseflow was diluted during the melt season in May and June of 2012. Multiple chemical and isotopic tracers were used to develop a robust three-component (groundwater, soilwater and precipitation) mixing model for runoff generation. The concentrations of weathering ions decreased with the increased discharge during the melt. Soilwater was responsible for about 60% of the streamwater on the hydrograph in the melt season. The infiltration of the meltwater from the snowpack and the thawed water from the seasonal frost to the baseflow existed. The tritium concentrations indicated that there was fast moving hydrogeological system within the basin. The baseflow was also characterized as relatively enriched in both 13C and 14C, and concentrated in DIC. DIC was the major loss of carbon in Wolf Creek Research Basin.Le pergélisol est grandement sous-jacent dans les bassins-versants à haute latitude. Cette étude examine le processus de ruissellement et le comportement des eaux souterraines dans un bassin-versant subarctique de Wolf Creek, à Whitehorse, territoire du Yukon au Canada. Les eaux souterraines soutenaient l’écoulement fluvial et dominaient l’hydrographe comme débit de base durant la majorité de la période d’étude. Le débit de base était concentré d’ions dissipés. Par contre, le débit de base était dilué durant la saison des fontes au mois de mai et juin 2012. Plusieurs traceurs chimiques et isotopiques étaient utilisé afin de développer un modèle de trois composants (eau souterraine, eau interstitielle de sol et précipitation) de ruissellement. Les concentrations de la déségrégation des ions diminuaient avec l’augmentation du débit durant la fonte. Les eaux interstitielles des sols étaient responsables de 60% de l’eau de ruisseau sur l’hydrographe durant la saison de fontes. L’infiltration de l’eau de fonte du manteau neigeux et l’eau du gel du débit de base existaient. Les concentrations de tritium indiquent qu’il y avait un système hydrogéologique qui se déplaçait à grande vitesse dans les limites du bassin. Le débit de base était aussi caractérisé comme étant enrichi en 13C et 14C, avec des concentrations en carbone inorganique dissous.

This thesis applies a novel method of change detection, the Landsat Image Stack Trend Analysis method to the monitoring of retrogressive thaw slumps in the Richardson Mountains, NWT. This method represents a significant improvement upon previous methods of thaw slump monitoring, which utilized air photos and high-resolution satellite imagery. This method applies Tasseled Cap brightness, wetness and greenness indices to Landsat TM/ETM images acquired between 1985 and 2011 and analyzes the temporal change of each pixel for the different indices values. This method is useful in retrogressive thaw slump monitoring in two ways. First, by creating a map showing the linear change over time from 1985 to 2011, retrogressive thaw slumps can be easily identified, as they are more dynamic than the surrounding tundra. In total, 251 thaw slumps were identified within an area of roughly 18 000km2. Second, thaw slump activity, from initiation, growth and stabilization can be studied by plotting the annual vegetation index pixel values of adjacent pixels in a thaw slump. This method allows for the efficient extraction of annual thaw slump headwall retreat rates, provided the availability of cloud-free imagery. The retreat rates of 16 slumps were extracted, which were found to have an average annual retreat rate of 11.8 m yr-1.

Reliable determinations of ecosystem scale fluxes of net carbon (C) and greenhouse gases for northern peatland ecosystems are of great value to determine the impact of soil warming and altered precipitation on emissions. Additionally, few studies have been performed which measure the C fluxes, particularly methane flux (FCH4), during the spring melt and fall freeze up periods, therefore making it difficult to provide adequate annual C estimates from northern peatland ecosystems. This study aimed to determine ecosystem scale FCH4 from a eutrophic Subarctic fen at Churchill, Manitoba (58°45'N 94°4'W), to understand (a) seasonal trends over two consecutive growing seasons,(b) if over-winter stored CH4 was released as a pulse during the spring-melt period, and (c) soil temperature - FCH4 relations for modelling FCH4 over the spring-melt period. An ecosystem scale methane (CH4) and carbon dioxide (CO2) flux measurement system using the eddy covariance (EC) technique was used from late-June to mid-October of 2008 and early-June to late-September of 2009, with focus on the spring-melt period of late-May to mid-July of 2009. The EC flux measurement system consisted of a closed-path RMT-200 Fast Methane Analyzer (Los Gatos Research Inc.) along with a LI-7500 open-path CO2/H2O gas analyzer (LI-COR Biosci.) and a CSAT3 3-dimensional sonic anemometer (Campbell Sci.). The system was powered by a combination of wind, solar, and gas electric generation. The EC flux measurement system provided seasonal FCH4 values of 0 – 90 nmol CH4 m-2 s-1, similar to previous studies in Subarctic and Arctic peatlands which incorporated the EC technique. A melt period CH4 emission burst was not observed, rather a gradual increase in emission over the spring period. Modelled FCH4 using a temperature-response curve relationship with soil temperature at 5 cm depth over the spring-melt period (May 30 – July 19, 2009) showed the fen to be a net source of CH4, of 1.4 mmol m-2 CO2 equivalent.

Roads and highways in cold regions are negatively affected by settlement of embankments in areas of degraded or degrading permafrost, particularly in areas with mean annual temperatures close to 0°C where permafrost is locally discontinuous. Climate warming and human activities can lead to increases in the temperature of permafrost and to thawing. In regions of discontinuous permafrost, thawing may produce thickening of the active layer, large settlements and non-recoverable shear deformations. These can cause potentially dangerous trafficability issues. The research program involved a test site on Provincial Road PR391, about 18 km northwest of Thompson, Manitoba. The foundation material of PR391 is currently classified as “degraded (thawed) permafrost”. The purpose of this research was to investigate and understand the performance of highway embankments on thawed permafrost. The research involved field instrumentation and data collection, laboratory testing, thermal modelling and frost heave predictions. The results of the field instrumentation and data collection show net heat flow into the ground, as well as development of cyclic seasonal gradients of total head. This is believed to be a significant original contribution to understanding the effects of climate change on highway infrastructure. The results also show that displacements observed at the PR391 embankment are a combination of consolidation and shearing strain of the foundation material. Most studies of embankments concentrate on vertical settlements. This research shows that horizontal movements are also present, a contribution that helps explain the mechanism of lateral spreading. The results of the laboratory testing show that the mechanical and shearing properties of the soil collected from the PR391 embankment are not significantly affected by differences in temperature once water in the soil has actually thawed. The results of the thermal modelling show reasonable trends in simulated ground temperatures compared with the data obtained from the thermistors underneath the embankment. The frost heave prediction of PR391 shows that in situ frost heave characteristics can be estimated by applying the Segregation Potential (SP) frost heave method in field conditions. This provides a valuable field study to the limited number of such studies of Segregation Potential, which are normally done under laboratory conditions.

This study looks at characterizing the terrigenous OC sources, like permafrost, of POC and DOC through 17 rivers and six soils of the Hudson Bay (HB) using lignin biomarkers, and Δ14C. Our findings show the dominance of the OC flux (89%) from the southwest Hudson Bay Rivers, especially from DOC (93%), shedding light on the sources and fate of OC in HB sediments. With warming, organic cryosols, with high OC content in the Cz horizon, have the potential to release as much as 1.5 gOC/m2 for every cm increase in active layer depth. The [Ad/Al] ratios, when combined with 14C ages of DOM, show that older SOC is being released in some rivers and is fresher than expected due to its preservation within permafrost. S/V and C/V ratios, are well correlated to latitude in DOM, reflecting the vegetation in their drainage basins and can be used to indicate OC sources.

An investigation of permafrost (permanently frozen soil) was conducted in Canada’s subarctic region of Northern Ontario. Environmental baseline conditions and permafrost states were estimated using seasonal freezing and thawing energies based on observed climate data and the Stefan equation. Field studies provided measurements of the active layer depths and validated the permafrost states; laboratory studies of the soil samples provided characterization for organic materials that have high affinity for soil moisture. Palsas (unique dome-like formations) were observed to have enhanced permafrost cores beneath a thermal insulating organic layer. With climate change, results suggest the possibility of shifts from the classification of continuous to discontinuous permafrost states in areas lacking the presence of organic materials that can have environmental and ecological impacts. Northern infrastructures may become destabilized with the degradation of permafrost while palsas may become lone permafrost refuges for biodiversity that depend on cooler ecosystems, such as polar bears.

An investigation of permafrost (permanently frozen soil) was conducted in Canada’s subarctic region of Northern Ontario. Environmental baseline conditions and permafrost states were estimated using seasonal freezing and thawing energies based on observed climate data and the Stefan equation. Field studies provided measurements of the active layer depths and validated the permafrost states; laboratory studies of the soil samples provided characterization for organic materials that have high affinity for soil moisture. Palsas (unique dome-like formations) were observed to have enhanced permafrost cores beneath a thermal insulating organic layer. With climate change, results suggest the possibility of shifts from the classification of continuous to discontinuous permafrost states in areas lacking the presence of organic materials that can have environmental and ecological impacts. Northern infrastructures may become destabilized with the degradation of permafrost while palsas may become lone permafrost refuges for biodiversity that depend on cooler ecosystems, such as polar bears.

The oxidation of sulfide minerals in mine waste rock has the potential to generate acidity and contribute sulfate, metals and other trace constituents to drainage. The rate and extent to which this process occurs are dependent upon climactic conditions and the overall hydrologic, geochemical and physical properties of the waste rock. A laboratory and field-based study is currently being conducted at the Diavik Diamond Mine in the Northwest Territories, Canada, which is investigating the evolution of waste rock exposed to subaerial conditions in the continuous permafrost region. Over the course of the mine life, Diavik is expected to generate a stock pile up to 120 Mt of low-sulfide waste-rock composed primarily of granite and granite pegmatite with smaller amounts of biotite schist which occurs as xenoliths, and trace contributions from diabase dykes. Waste rock is segregated based on sulfur content into Type I (< 0.04 wt % S), Type II (0.04-0.08 wt % S) and Type III (> 0.08 wt % S) rock. The Diavik Waste Rock Research Project includes four 2 m by 2 m lysimeter experiments, two each constructed with Type I and Type III waste rock. Also constructed were two well-instrumented, 15 m high test scale waste-rock piles, one composed of Type I and one composed of Type III uncovered waste rock, and one covered test pile based on a reclamation concept which consists of a Type III waste rock core, a 1.5 m glacial till layer, and a 3 m layer of Type I waste rock. In addition, instrumentation was installed in four locations of the operational waste-rock stockpile. The geochemical differences between the Type I and Type III lysimeters and test piles is discussed to compare the non-acid generating Type I waste rock with the potentially acid-generating Type III. The effluent from the Covered test pile retained the character of the Type III waste-rock core over the course of observation producing slightly acidic drainage, possibly due to a zone of unfrozen till on the crest as a result of heat trace within the test pile. Observations from the geochemistry of the Type III waste rock will also be compared to mineralogical analysis from Type III samples collected during installation of instruments in the full scale waste-rock stockpile. Due to the low concentration of sulfide minerals, advanced techniques such as SEM and synchrotron-based analyses were employed for in-depth characterization of initial sulfide-oxidation products. SEM images and elemental mapping reveal development of reaction rims on many pyrrhotite grains, but lower instances of weathering of pyrite. Distinct zonation of weathering trends between depths within the stockpile was also absent. These observations indicate that the waste rock is in the early weathering stages may not yet be affected by the formation of permafrost. These observations act as a baseline for future studies. Correlations between the mineralogical and geochemical analyses, in addition to future monitoring and continuation of these studies, will assist in understanding the evolution of waste rock stored in a permafrost environment.