T M IMPACT of GLACIER RECESSION UPON THE
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TmIMPACT OF GLACIERRECESSION UPONTHE DISCHARGEOF THE BOW RIVER ABOVEBANFF, ALBERTA. 1951-1993 Christopher Hopkinson B.Sc., Manchester University, 1995 THESIS Submitted to the Department of Geography in partial fulfilrnent of the requirements for the Master of Environment Studies degree Wilfnd Laurier University 1997 " Christopher Hopkinson, 1997 National Library Bibliothèque nationale of Canada du Canada Acquisitions and Acquisitions et Bibliographie Services services bibliographiques 395 Wellington Street 395, nie WelIingtori OttawaON K1A ON4 OttawaON K1AON4 Canada Canada Yaw a@ V& réfckmœ Our Me Nane dmmce The author has granted a non- L'auteur a accordé une licence non exclusive licence allowing the exclusive permettant à la National Library of Canada to Bibliothèque nationale du Canada de reproduce, loan, distribute or sell reproduire, prêter, distribuer ou copies of this thesis in microform, vendre des copies de cette thèse sous paper or electronic formats. la forme de microfichelfilm, de reproduction sur papier ou sur format électronique. The author retains ownership of the L'auteur conserve la propriété du copyright in this thesis. Neither the droit d'auteur qui protège cette thèse. thesis nor substantial extracts fkom it Ni la thèse ni des extraits substantiels may be printed or othefwise de celle-ci ne doivent être imprimés reproduced without the author's ou autrement reproduits sans son permission. autorisation. This niesis is dedicated to rny brother Michael and dl the mernories we never bad a chance to share. Three methods have been used to explore the volumetric change of glaciers in the Bow Basin above Banff for the years 1951 to 1993. Using aerial photography, the extent of glacier covers for the two years were mapped at a scale of 1:50,000. The first volumetric calculation of glacier loss was based on inventory criteria; the second a hypsographic curve method based on Young's investigations in Mistaya Basin (1991) and the third stereo air photogrammetry and DEM cornparisons using computer software. These methods were applied to the highly glacierized Hector Lake catchment within the Bow Valley and then extrapolated up to the whole basin above Banff. Reasonable agreement was achieved between the methods and the magnitude of glacier loss is estimated to be between 930 and 1400 m3xlo6 w.e. for the entire 42 year period. The bulk glacier "wastage" estimate was divided into proportions using the Peyto Glacier mass balance record. Unfortunately, the record began in 1966 and a back-cast to 1952 was necessary. The mass balance model proposed by Letreguilly (1 988) was considered inappropnate for this task due to it not adequately representing the observations of recession on Peyto for 1952 to 1965. A new model utilizing Banff maximum summer temperature and Lake Louise snow course data was constmcted. The proportions of seasonal wastage contributions to river flow were estirnated using a multiple regression model of monthly average temperature and precipitation with snow course data as the antecedent condition determinant. This model was used to predict the shape of the glacier (ice and firn) melt hydrograph from June to September. An estimate of the temporal variation of glacier recession inputs to the Bow River hydrograph at Lake Louise and Banff was facilitated by comparing known basin yields with the modelled "wastage" values. For 1952 to 1993 at Banff, the average annual wastagehasin yield ratio is found to be around 2.3%; for 1965 to 1992 (years of available data) at Lake Louise the same ratio is 4.5%. For the extremely low flow year of 1970 these ratios increase to 12.5% and 16.2% respectively. The proportion of flow derived fiom glacier recession in August of this year is estirnated to be around 53% for Banff and 84% for Lake Louise. It is thought that the basin scale extrapolation may lead to under- estimations of wastage but the mass balance back-cast is more likely to preferentially weight wastage contributions toward the latter part of the time series. Many thanks to everyone that helped, especially my parents, Gordon Young, Mike English, Sophie Gaborit, Scott Munro, Grant Simpson, Gordon Gracie, Richard Tychansky, Ken Hewitt, Alexi Zawadzki, Andrew Gould, Dr Bell, Dr Donahey, the nurses at Bow Valley General, Dave the "Performance Guy", my piranha; Adele, Alberta Environment; particularly the operational guys and holders of "purse strings", Mike Demuth of National Hydrology Research Institute, Tim Davis of Water Survey Canada, the nice National Air Photo Library people, the Whyte Museum of the Canadian Rockies, CRYSYS, Atmospheric Enwonment Service, Parks Canada, Alpine Club of Canada, Dave Collins, RTS; my faithful steed, Yeuval; the Israeli army officer chappy, Beth, the Num-ti-ja Lodge staff and, of course, Mark Saunders; the philanthropie folk singer. And, hally, the greatest th& of dl go to the mountains and glaciers; for being there and providing me with inspiration and the impetus to spend as much time as 1 am able within theû comforting embrace. A~STRACT III CWTER ONE:INTRODUCTION 1 1.1 PREFACE 1 1.1.1 Glacier Recession 1 1.1.2 Bow River as a Resource 4 2.2 OVERVIEWOF MOUNTAIN HYDROLOCY 2.2.1 Precipitation 2.2.2 Slow Hydrological Transfer Mechanisms 2.2.3 Hydrological Outputs 3.2 STEREOAIR PHOTOGRAMMETRY 3.2.1 Introduction 3.23 Stereoscopic ParaUar 3.2.3 Ground Control and Image Scale 3.2.4 Stereoscopic Plotting 3.3 DIGITALELEVATION MODELS 3.3.1 Introduction 3.3.2 Irregular Method 3.3.3 Grid Method 3.4 VURFER*@ SOFTWARE 3.4.1 Introduction 3.4.2 Grid Creation and Blanking 3.43 AnalyticaI Functions 4.2 ESTIMATIONOF GLACIERVOLUME LOSS, 1951-1993 4.2.1 Sumrnary 4.2.2 Obtaining the Aerial Imagery 4.23 The Glacier Coverage Map for Hector Lake Basin, 1951 & 1993 42.4 Inventory Method 4.2.5 Hypsographic Curve Method 4.2.6 Photogrammetrical Method 4.2.7 Extrapolation up to the Bow Basin Above Banff and Lake Louise 4.2.8 Glacier Volume Water Equivalence 4.3 ANNUALGLACIER WASTAGE ESTIMATIONS 4.3.1 Peyto Glacier Mass Balance 43.2 Back-cast of Peyto Glacier Mass Balance Record 4-33 Calculating the Annual Wastage Proportions 4.4 SEASONALGLACIER WASTAGE CONTRIBUTIONS 4.4.1 Introduction 4.4.2 Peyto Glacier Seasonal Melt Hydrograph 1967-74 4.43 Multiple Regression Model 5.2 GLACIERVOLUME LOSS 1951-1993 5.2.1 Inventory Method 5.2.2 Hypsographic Curve Method 5.2.3 Photogrammetrical Method 5.2.4 Summary of Volume Calculations and Water Equivalence 5.4 MONTHLYPROPORTIONS OF GLACIERWASTACE 5.4.1 Idealised Ice Melt Hydrograph 5.4.2 Multiple Regression Model Using Meteorological Variables 6.1 REVIEWOF THE TECHNIQUESUSED 6.1. 1 Mapping Glacier Extents 6.1.2 Volume Calculations 6.13 Validity of Extrapolating up to the Scale of the Bow above Banff 6.1.4 Annual Wastage Proportions 6.1.5 Monthly Wastage Proportions 6.2 THEIMPACT OF GLACIERRECESSION ON THE FLOWOF THE BOWRIVER 6.2.1 1952 - 1993 6.2.2 Time Lags 6.2.3 Evaporative Water Losses 6.2.4 The Future 6.2.5 Ciimatic Interactions CEUPTERSEVEN: CONCLUDING REMARKS 7.1 KEYFINDINGS 7.1.1 Glacier Loss in the Bow vaiiey 1951-1993 7.1.2 Impact of Glacier Wastage on the Bow River Hydrograph at Banff, 1951-1993 7.13 Implications for Future Water Avaiiabiiity in the Bow at Banff 7.2 EVALUA~ONOF METHODS 7.2.1 Volumetric Change 7.2.2 Annual Weighting of Glacier Wastage 7.2.3 Seasonal Wastage Hydrograph 7.2.4 Summary of Errors 7.3 SUGGESTIONSFOR IMPROVEMENT REFERENCES APPENDICES Table 4-1 Estimated Average Glacier Depths (Stanley. 1970) .....................................41 Table 4-2 Peyto Glacier surface melt figures for 1966-89 (Young. 1991) and extrapolated for 1952.1993. ....................................a..m.~~*m.~mmm~~~~~~*~~a~..*m*.~~~*~.*~*~~~~*~~.~43 Table 5-1 Hector Basin glacier volume estimation, 1951 .............................................65 Table 5-2 Hector Basin glacier volume estimations, 1993 ............................................66 Table 5-3 Areal extents of glacier cover per lOOm elevation band ..............................68 Table 5-4 Glacier volume loss using hypsographic and surface melt data .................70 Table 5-5 Ground control points used in photogrammetrical analysis ...................... 70 Table 5-6 Surfer grid file summaries with volume cornputetions ...............................79 Table 5-7 Summary of the glacier wastage estimations............................................ 80 Table 5-8 Peyto mass balance figures, actual and modelled ........................................ 81 Table 5-9 Estimated annual proportions of glacier wastagehasin yield for Banff and Lake Louise....................................................................................................... 83 Table 5-10 Estimated Peyto Glacier melt 1967-74 (after Young, 1982) with average monthly proportions ................................................................................................ 86 Table 5-11 Ideaiised monthly glacier volume loss / basin yield for Bow above Banff and Lake Louise....................................................................................................... 86 Table 5-12 Modelled monthly gtacier volume loss 1 basin yield for Bow above Banff and Lake Louise.. ....................................... .......................................................88 Table 6-1 Glacier volume error estimations using the Inventory Method ................. 92 Table 6-2 Annual & monthly summary of wastagehasin yield at Banff ..............112 Table 7-1 Volume calculations of glacier wastage for Hector Lake Basin with areal extrapolation