Glaciers provide late-summer runoff to the Columbia River Basin, but few studies quantify glacier runoff and its relation to recent climate variations. This study used digital photogrammetry to map glacier area and volume change in the Canoe Basin, headwaters of the Columbia River, from 1948 to 2005. Historic streamflow and glacier contribution to streamflow were simulated using the HBV-EC hydrologic model. From 1948 to 2005, glacier area and volume decreased by -3.8 ± 0.44 km² (-6.8 ± 0.79%) and -0.23 ± 0.14 km³, respectively. The majority of glacier change occurred from 1985 to 2005. Increasing streamflow from 1947 to 2006 is likely related to increased summer precipitation and not enhanced glacier wastage. Glacier contribution to streamflow decreased from 1947 to 2006, with a higher rate of decrease from 1985 to 2006 than from 1947 to 1985. From 1947 to 2006, glaciers contributed 14-16% (32-38%) of total annual (August) streamflow.
The relation between sediment yield and glacier fluctuations at timescales less than a century remains uncertain. The primary goal of this study was to assess the influence of glacier activity on sediment yield within the Peyto Lake watershed. The research focused on a small alpine watershed in the Rocky Mountains of Alberta containing Peyto Glacier and the proglacial Peyto Lake. Using photogrammetric methods I determined changes in length, area, and volume of Peyto Glacier from a topographic survey map (1917) and 18 sets of aerial photographs (1947-2005). I also collected 18 sediment cores from Peyto Lake that consists of laminated, silt-clay couplets which can be shown through ¹³⁷Cs activity to be clastic varves. Varve thickness and sediment properties were combined to produce an annual record (1917-2010) of specific sediment yield (SSY) for the watershed. I then compared the SSY record to dimensional changes of Peyto Glacier as well as available mass balance records, hydrometric records, and climate records over the study period (1917-2010). Over the period 1917-2005, Peyto Glacier retreated 2198 ± 18 m, shrank 4.0 ± 0.9 km², thinned 44 ± 31 m, and lost 581 ± 404 x 10⁶ m³ water equivalent (w.e.). I measured an additional 85 ± 4 x 10⁶ m³ w.e. of ice loss from thinning ice-cored moraines adjacent to the glacier. Over the period 1917-2005 SSY averaged 446 ± 176 Mg km²yr⁻¹, which is among the highest measured yields in the Canadian Cordillera; however, this value is relatively low for glaciated basins worldwide. The SSY record has a poor relation to short-term dimensional changes of Peyto Glacier, likely due to the complexity of sediment transfers in proglacial environments. Long-term trends in SSY are hypothesized to arise from increasing (1870-1940) and decreasing (1970-2010) glacier contribution to streamflow over the past century.
This thesis presents two cost-effective techniques for landslide mapping in large, remote regions. The first technique uses ASTER satellite imagery to characterize and determine landslide distribution for part of the South Nahanni watershed. Results obtained from this study confirm that ASTER images are suitable for regional-scale landslide mapping. The second technique involved the creation of landslide susceptibility models for debris flow and rock/debris slides using logistic regression analysis. Cross validation confirmed the models' success. The debris flow model performed best whereas the rock/debris slide model was only moderately successful. Taken together, the two methods developed in this thesis provide a means to conduct a preliminary landslide investigation in large, remote regions or in developing countries where data are limited or site investigation is not possible. Maps produced from this analysis can be used to gain information on areas susceptible to landslides and to target key areas remotely before conducting field investigations. --P. ii.
The goal of this study is to assess the performance of melt models of varying complexity to simulate snowmelt under different aspect, forest cover, and input data conditions in the British Columbia interior. Observed snow water equivalent data from the 2008 melt season were used to compare the performance of a basic temperature-index (TI) model, three modified TI models, and a simple energy balance model (EBM). The largest (smallest) values of NSE (RMSE) for the snow course sites were 0.81 (0.0243 m) for the TI models and 0.58 (0.0362 m) for the EBM. At the automatic snow pillow (ASP) the largest (smallest) values of NSE (RMSE) were 0.54 (0.0055 m) for the TI models and 0.65 (0.0048 m) for the EBM. At the snow course sites all TI models performed better than or equivalent to the EBM. At the ASP one EBM version performed better than the TI models. --P.ii.
Documenting past climate dynamics aids in our understanding of the climate system. In order to assess future climate change it is valuable to examine the connectivity of climatic phenomena between hemispheres. Although studies that estimate past climate fluctuations are common in the Northern Hemisphere, fewer well-constrained glacier chronologies exist in the Southern Hemisphere. The assessment of past glacier activity remains the most direct method of creating a climatic record for a region, and the comparison of these glacial chronologies tests the synchronicity of climatic change between regions. This study investigates inter-hemispheric synchronicity by developing a detailed glacier history in southern Patagonia for comparison to robust glacier chronologies from the northwestern North America. Five Neoglacial advances of Stoppani Glacier in the Cordillera Darwin of southern Patagonia broadly correspond to the Neoglacial activity documented in northwestern North America. This Stoppani Glacier chronology is based on radiocarbon-dated detrital and in situ plant material contained within the northeastern lateral moraine stratigraphy. The age range from dated plant material records the first Neoglacial expansion of Stoppani Glacier which, overlaps with the end of the 4.2 ka Advance' reported throughout northwestern North America. Stoppani Glacier advanced multiple times between 3500-1900 cal yr BP which overlaps with the 'Peyto-Tiedemann Advance' documented in northwestern North America. The lacustrine record from nearby Lago Roca also suggests that local sea level lowered during the 3500-1900 cal yr BP period, resulting in the isolation of the lake from the Beagle Channel ca. 2300 cal yr BP. Plant material from within till at Stoppani Glacier and lacustrine sediments from Lago Roca yield an age range for the last advance of glaciers in the Cordillera Darwin the range coincides with the end of the wide-spread Little Ice Age Advance' documented throughout northwestern North
This thesis is a five-chapter investigation of glacier change in the Cariboo Mountains of British Columbia. In chapter one I discuss the importance of glaciers, introduce the glaciers of the Cariboo Mountains, and outline the objectives and structure of this thesis. In chapter two I compare three methods to estimate annual glacier mass balance of a 9.6 km2 mountain glacier for years 2009, 2010, and 2011. I find two geodetic methods, real-time kinematic GPS (global positioning system) and photogrammetry, to provide a valuable measure of glacier-wide annual mass balance that is complementary to the glaciological method. In chapter three I reconstruct the terminus position of the same mountain glacier for the period 1959-2007 from a series of annual push moraines. Annual recession of this glacier, the longest record for a North American glacier, is controlled by air temperature during the ablation season and accumulation season precipitation during the previous decade. I demonstrate an immediate glacier terminus reaction to summer and annual mass balance and a delayed reaction to winter and annual balance. In chapter four I calculate dimensional change for 33 representative glaciers in the Cariboo Mountains for the latter half of the twentieth century. I show the period 1952-1985, when nine glaciers advanced, to be one of little net change for Cariboo Mountains glaciers. After 1985, however, rates of recession and thinning increased substantially. Comparison with climatological records reveals this marked change is due to both increased ablation season temperature and decreased accumulation season precipitation. I show glacier response to climate over this period to be highly variable and that relations between response and glacier morphometry are not consistent temporally. In chapter five I conclude this thesis with the progress gained through my research, study limitations, and the knowledge gaps that remain. Finally, I make 10 recommendations that will address knowledge gaps, and improve understanding of glacie
Glaciers play an important role in the evolution of many mountain landscapes. The primary goal of this study is to model rates of contemporary glacier erosion through numerical modeling. The first part of this study uses a regional glaciation model and couples to it (i) a process-driven erosion model that includes abrasion and quarrying and (ii) a sliding-based power relation erosion model as used in landscape evolution models. A sensitivity analysis reveals that abrasion is sensitive to the grain-size distribution, the choice of sliding parameters, and the debris hardness/concentration parameter. Quarrying rates primarily depend on the height and spacing of bed irregularities. The sliding model is sensitive to a proportionality constant which is not physically constrained. The second part of the study uses the developed erosion models to estimate glacier erosion for Peyto Glacier. The models predict higher rates of primary glacier erosion than those estimated by sediment recovery from Peyto Lake. Contrary to observations of sediment yield from the catchment, both models predict a decrease in erosion rates during glacial retreat. Changes in sediment storage beneath the glacier are believed to account for the discrepancy between observed and modeled sediment yield. Over the past 2000 years, major differences are seen between the models during extreme climate periods such as the Medieval climate anomoly (MCA) and the Little Ice Age (LIA). These differences do not depend on the exact choice of modeling parameters but rather the inter-decadal to century-scale variability inherent in the climate proxy data used to force the models. --Leaf i.
Glaciers adjust their physical properties to changes in climate, but long records of glacier change needed to examine this relation are spatially and temporally limited. I determined changes in glacier area in the central and southern Canadian Rocky Mountains and changes in length, area, elevation, and volume of the Columbia Icefield over the past nine decades. I used Interprovincial Boundary Commission Survey (IBCS) maps of the Alberta-British Columbia (BC) border (1903-1924), aerial photographs (1948-1993), BC Terrain Resource Information Management (TRIM) data (1982-1987), and satellite imagery (1999-2009) in my analysis. From 1919-2006, total glacierized area in the Canadian Rocky Mountains decreased by 590 ± 100 km² (40 ± 7%); glaciers smaller than 1.0 km² experienced the greatest percentage loss. Slope and minimum elevation are negatively correlated with absolute area loss, and mean and median elevations are negatively correlated with relative area loss. From 1919-2009, glaciers of the Columbia Icefield retreated 1149.9 ± 34.1 m, decreased 59.60 ± 1.19 km² (22.5 ± 5.0%), thinned 49.4 ± 25.2 m w.e., and lost 14.30 ± 2.02 km³ w.e. Debris-covered ice thinned 30-60% less than bare ice. Changes in temperature and precipitation explain some of the observed changes. I detected a lag of two to ten years between climate and glacier response.
