Major Ion and Stable Isotope Geochemistry of the Bow River, Alberta, Canada

University of Calgary PRISM: University of Calgary's Digital Repository

Graduate Studies Legacy Theses

2011 Major Ion and Stable Isotope Geochemistry of the Bow River, Alberta, Canada

Chao, Yi-Ju June

Chao, Y. J. (2011). Major Ion and Stable Isotope Geochemistry of the Bow River, Alberta, Canada (Unpublished master's thesis). University of Calgary, Calgary, AB. doi:10.11575/PRISM/20293 http://hdl.handle.net/1880/48562 master thesis

University of Calgary graduate students retain copyright ownership and moral rights for their thesis. You may use this material in any way that is permitted by the Copyright Act or through licensing that has been assigned to the document. For uses that are not allowable under copyright legislation or licensing, you are required to seek permission. Downloaded from PRISM: https://prism.ucalgary.ca UNIVERSITY OF CALGARY

Major Ion and Stable Isotope Geochemistry of the Bow River, Alberta, Canada

Yi-Ju June Chao

A THESIS

SUBMITTED TO THE FACULTY OF GRADUATE STUDIES

IN PARTIAL FULFILMENT OF THE REQUIREMENTS FOR THE

DEGREE OF MASTER OF SCIENCE

DEPARTMENT OF GEOSCIENCE

CALGARY, ALBERTA

APRIL 2011

The author of this thesis has granted the University of Calgary a non-exclusive license to reproduce and distribute copies of this thesis to users of the University of Calgary Archives.

Theses and dissertations available in the University of Calgary Institutional Repository are solely for the purpose of private study and research. They may not be copied or reproduced, except as permitted by copyright laws, without written authority of the copyright owner. Any commercial use or re-publication is strictly prohibited.

The original Partial Copyright License attesting to these terms and signed by the author of this thesis may be found in the original print version of the thesis, held by the University of Calgary Archives.

Please contact the University of Calgary Archives for further information: E-mail: [email protected] Telephone: (403) 220-7271 Website: http://archives.ucalgary.ca

Abstract

Natural and anthropogenic impacts on the major ion and isotope geochemistry of the Bow River were evaluated between 2007 and 2008 using integrated hydrometric, chemical and isotopic analyses. Under the influence of mineral dissolution, calcite- gypsum solubility, and wastewater and prairie tributary discharges, the river water evolved from a Ca-Mg-HCO3 type in the Rocky Mountain headwaters towards compositions elevated in Na, SO4, Cl and NO3 with downstream distance. Mass loads of

SO4 and NO3 increased with flow distance, and concentrations of SO4 and NO3 were highest throughout the river during baseflow periods in fall and early spring. Isotope mass balances using two end-member mixing models demonstrated that riverine SO4 is a mixture of 53-63% of mainly evaporite derived sources from the Rocky Mountains, 27

37% of oxidized S and wastewater SO4 sources from the prairies, and 10% of wastewater derived SO4 from Calgary. Riverine NO3 is mainly derived from nitrification in forest soil and wastewater effluents, and is more impacted by anthropogenic sources than SO4.

Wastewater derived NO3 accounted for 84-92% of the NO3 load downstream of Calgary as opposed to ≤50% in the upstream reaches. This study demonstrates that sources of

SO4 and NO3 in the Bow River can be effectively differentiated and apportioned via integrated isotopic techniques.

iii

Acknowledgements

I am very fortunate to have had the opportunity to work on this project as a part of one of the most dynamic and resourceful research groups in the field of stable isotope and applied geochemistry. This project would not have been possible without the generosity of my supervisors and financial supports from NSERC and AICWR. I thank Dr. Bernhard Mayer for his patience and support throughout the course of the project, and especially for his thorough review and insightful critiques of my thesis. One of the most valuable experiences as a graduate student with AGg has been its active support for student participation in local and international conferences. The intellectual stimulation gained from sharing discussions with other researchers in the scientific community was invaluable. I would also like to thank Dr. Cathy Ryan for her lively discussion and debate about my data, and for suggesting ways to improve the graphical representation of some of the otherwise complicated figures.

Thanks to the staff at AGg (Maurice, Michael and Tim), the Isotope Sceince Laboratory (Steve, Jesusa, Nanita and Yan) and the Environmental Science Laboratory (Farzin) at the University of Calgary for helping me with technical problems and analytical works. Thanks to Katie Hogue, Katrina Cheung, and Norka Marcano for responding to my call for help with fieldwork. A special thank you goes to Trevor Hirsche for his dedication as my field assistant for 1 year, and for his generous help later in proof reading some of the longest unpolished thesis chapters. I am also indebted to my friend, Ellen for her editorial suggestions and critical comments about my writing.

To Eli and Ann, thank you for your hospitality and for welcoming me to stay at your fabulous house whenever I visit Toronto. You had given me some of the best New Years. To my good old friends Eric and Karina in Toronto, thank you for feeding me and accommodating me during my visits. To those dainty spirits in the girl’s office in ES 506, thank you for keeping cheerfulness going. Finally, I must thank Christian. Because of you, Ookie survived starvation.

iv Table of Contents Approval Page...... ii Abstract...... iii Table of Contents...... v List of Tables ...... viii List of Figures and Illustrations ...... x List of Symbols, Abbreviations and Nomenclature...... xvi

CHAPTER 1: INTRODUCTION...... 1

CHAPTER 2: BACKGROUND...... 6 2.1 The Bow River Basin...... 6 2.2 The Climate of Southern Alberta...... 6 2.3 The Physiographic Regions ...... 7 2.4 Geology...... 9 2.5 Soil Types ...... 11 2.6 Groundwater Chemistry on the Prairies...... 13

CHAPTER 3: SAMPLING AND ANALYTICAL METHODS...... 15 3.1 Fieldwork...... 15 3.2 Laboratory Analyses...... 19 3.3 Calculations ...... 21

CHAPTER 4: ISOTOPIC COMPOSITIONS OF WATERS ...... 27 4.1 Introduction...... 27 4.2 Precipitation across the Bow River Basin...... 29 4.3 Hydrographs of the Bow River...... 33 4.4 Isotopic Compositions of Waters...... 36 4.5 Summary...... 47

CHAPTER 5: MAJOR ION CHEMISTRY OF THE BOW RIVER ...... 48 5.1 Introduction...... 48 5.2 Discharge and Solute Loads in the Bow River...... 50 5.2.1 Upstream of Calgary...... 53 5.2.2 Downstream of Calgary...... 55 5.3 Geochemistry of the Major Ions ...... 61 5.4 The Basic Water Types...... 65 5.5 Tracing Chemical Variations with Ion Ratios ...... 71 5.5.1 The Rocky Mountain Headwaters...... 71 5.5.2 Prairie Tributaries and Calgary’s Wastewaters ...... 73 5.6 Seasonal Variations of Ion Ratios...... 74 5.7 Summary...... 77

CHAPTER 6: THE SOURCES OF SULPHATE IN THE BOW RIVER...... 79 6.1 Introduction...... 79 6.2 SO4 in the Bow River...... 82

v 6.2.1 Concentration-Flow Relationships ...... 82 6.2.2 Seasonal Variations along the Bow River...... 84 6.2.3 Tracing Mass Loads of SO4 along the Bow River ...... 86 6.3 The Isotopic Composition of SO4 ...... 90 6.3.1 SO4 in the Environment...... 90 6.3.2 Calgary’s Wastewater SO4 ...... 91 6.3.3 SO4 in Tributaries...... 92 6.3.4 SO4 in the Bow River ...... 93 18 6.4 Relationship between δ O Values of SO4 and H2O...... 98 6.5 Mass Balance Calculations ...... 101 6.6 Summary...... 103

CHAPTER 7: IDENTIFYING THE SOURCES AND TRACING THE FATE OF NITRATE IN THE BOW RIVER ...... 105 7.1 Introduction...... 105 7.2 NO3 Concentrations in the Bow River...... 108 7.3 The Bow River NO3 – Flow Relationships...... 111 7.3.1 Upstream of Calgary...... 111 7.3.2 Downstream of Calgary...... 114 7.4 N from Calgary’s Wastewater Treatment Plants ...... 116 7.5 NO3 in the Prairie Tributaries ...... 117 7.6 Mass Loads of NO3 along the Bow River...... 120 7.7 Isotopic Compositions of NO3 ...... 125 7.7.1 NO3 in the Environment ...... 125 7.7.2 Calgary’s Wastewater Effluents ...... 126 7.8 Isotope Mass Balance Estimations ...... 135 7.9 Summary...... 142

CHAPTER 8: CONCLUSIONS ...... 144 8.1 Isotope Hydrology of the Bow River...... 144 8.2 Major Ion Chemistry of the Bow River ...... 144 8.3 Source Identification and Apportionment for SO4 and NO3 in the Bow River ...145 8.4 Final Summary...... 146 8.5 Future Research ...... 146

REFERENCES ...... 149

APPENDIX A: SUMMARY TABLE OF SAMPLING SITES...... 163

APPENDIX B: TABLES OF WATER ANALYSES...... 165

I – THE BOW RIVER ...... 165

II – TRIBUTARIES...... 175

III: WASTEWATER TREATMENT PLANTS AND SHORT-TERM SAMPLING SITES IN THE BOW RIVER IN CALGARY...... 182

vi APPENDIX C: SAMPLE CALCULATION FOR CALCITE SOLUBILITY AT 0ΟC AND 1 ATMOSPHERE ...... 186

APPENDIX D: ESTIMATED CONTRIBUTIONS TO THE TOTAL DISSOLVED SOLID CONCENTRATIONS IN THE BOW RIVER FROM DIFFERENT DISSOLVED CONSTITUENTS AND WATER TYPES ...... 188

APPENDIX E: SOURCES OF ARC-GIS BASEMAP FILES AND LIST OF SOFTWARES...... 190

vii List of Tables Table 3.2 Summary of concentration-flow relationships (y as concentrations in mg/l and x as flows in m3/s) used in calculating the Bow River’s annual solute loads upstream of the Bassano Dam. For those solutes without a concentration-flow relationship, flow-weighted average concentrations were used...... 23

Table 3.3 Summary of the concentration-flow relationships used in calculating the annual mass loads of the Bow River below the Bassano Dam at Bow City and Ronalane...... 24

Table 3.4 Correlation equations used in calculating the average isotopic compositions of SO4 in Chapter 6...... 26

Table 4.1 Summary of total monthly precipitation at Lake Louise, Banff, Calgary, Lethbridge and Brooks for 2007 and 2008 (data source: National Climate Data and Information Archive, Environment Canada 2010)...... 32

Table 4.2 Estimates of annual average discharges of the Bow River from Lake Louise to Ronalane and unknown discharge souces or sinks along the flow path. Discharge contributions from the Rocky Mountain headwaters, Calgary’s WWTPs and the prairie reaches were given in percentages...... 35

Table 4.3 Summary of regression equations between δ18O and δ2H values for the Bow River in each month...... 45

Table 5.1 The annual total ionic solute loads and flow-weighted TDS along the Bow River at Lake Louise, Canmore, Cochrane, Calgary, Carseland, Bow City and Ronalane in 2007 and 2008. Major inputs downstream of Calgary include the Highwood River and the wastewater effluents from both wastewater treatment plants - TPBB and TPFC. Diversion of irrigation water for the three irrigation districts (WID, BRID and EID) constitutes the major water withdrawals from the Bow River. Units are in GL (x109 L) for the total annual discharges and kilo tons (kt) or (x106 kg) for the total annual ionic solute loads...... 51

Table 5.2 The flow-weighted annual averages of the major ionic solute loads for the Bow River water along its flow paths, at the outlet of the Highwood River, in the major diversion canals (WID, BRID and EID), and from the wastewater effluents at TPBB and TPFC. These averages were computed from the values for 2007 and 2008 in Table 5.1. The units are in GL (x109L) for the averaged total annual discharges and in kilo tons (kt) or (x106kg) for the averaged total annual solute loads...... 52

viii Table 6.1 Estimated SO4 mass loads and unknown sources and sinks of SO4 along the Bow River. Percentage contributions from the Rocky Mountain headwaters, Calgary’s WWTPs and the prairie reaches were also calculated...... 89

Table 6.2 Isotopic compositions of SO4 of the treated wastewater effluents from Calgary’s two WWTPs and wastewater plume in the Bow River...... 91

Table 6.3 Summary results (italic) of the isotope mass balance calculation. Underlined mass loads values at Lake Louise were modified to satisfy the boundary conditions (i.e. mass load and δ34S and δ18O values at Canmore) of the isotope mass balance...... 102

Table 7.2 Estimations of the total annual NO3 load in the Bow River and the Highwood River in 2007 and 2008. Major withdrawals and point sources are included with an upper estimate of the mass load contributions from the prairie tributaries. Values for the Bow River, the Highwood River and major withdrawals and inputs are summarized from Table 5.1 and 5.2 in Chapter 5...... 124

Table 7.3 Summary of results and the parameters used in the isotope mass balance calculations. The estimated range of isotopic values from conservative mixing 18 of NO3 and nitrified NH4 are shown in italic. The δ ONO3 values (underlined) from presumed nitrification of NH4 are estimated using isotopic mass balance whereas the rest of the isotopic values are measured...... 127

Table 7.4 Isotopic compositions of NO3 and NH4 for samples with significant amounts of NH4...... 127

ix List of Figures and Illustrations Figure 1.1 Maps showing reach-specific data availability for IFN determinations in the South Saskatchewan River Basin modeled for (a) integrated ecosystem and (b) water quality (after Clipperton et al. 2003)...... 3

Figure 2.1 a) The five major physiographic regions of Southern Alberta and b) the zoom in view of shaded area in a) showing physiographic subdivisions on the prairie plains surrounding the Bow River Basin between Calgary and the confluence with the South Saskatchewan River (modified after Pettapiece 1986). ... 8

Figure 2.2 Geological formations of the South Saskatchewan River Basin in Alberta showing the Bow River Basin (red) and sampling locations along the Bow River from Lake Louise (0 km) to Ronalane (571 km) (compiled in ARC-GIS)...... 11

Figure 2.3 Soil types in southern Alberta and sampling sites along the Bow River in distances (km) with respect to Lake Louise (compiled in ARC-GIS)...... 12

Figure 2.4 Hydrochemical map of shallow bedrock aquifers in the Interior Plains of Canada showing regions of Na-HCO3 (green), Ca-Mg-SO4 (yellow), Mg-Ca HCO3 (blue) and Na-SO4 (light yellow) waters. Contours in blue are baseflow indexes in glm (gallon per minute per square miles) (modified after Meyboom 1967)...... 14

Figure 3.1 Sampling sites along the Bow River from Lake Louise in the Rocky Mountains to Ronalane near the mouth on the Eastern Alberta Plains. Sampling sites are labelled with their relative downstream distances in kilometres with respect to Lake Louise (0 km)...... 16

Figure 3.2 Sampling locations of the prairie tributaries within WID, BRID and EID of the Bow River Basin. Of the six AAFRD water quality sites (red dots), five were sampled which included W-R2 (CF Ck.), BR-R1 (B1516), BR-R2 (B1416), E-R5 (E1413) and BR-R5 (B1212) (map modified after AAFRD 2007)...... 17

Figure 3.3 Electrical charge balance relationship of the major ions...... 19

Figure 4.1 Map of the total annual precipitation across the three major sub-basins of the South Saskatchewan River in Alberta. The Bow River Basin is outlined in red with the major sampling stations labelled as distances in km relative to Lake Louise (0 km) (produced using Arc-GIS and Arc Canada v.3 database)...... 30

Figure 4.2 Monthly total precipitation in the Rocky Mountains at Banff, on the Western Alberta Plain at Calgary and on the Eastern Alberta Plain at Lethbridge (data source: National Climate Data and Information Archive, Environment Canada 2009)...... 33

x Figure 4.3 Daily flow of the Bow River at Lake Louise, Canmore, Cochrane, Carseland and Ronalane throughout a) 2007 and 2008, and b) during the field sampling period from June 2007 to July 2008. The shaded area shows when flows at Ronalane were significantly lower than those at Cochrane and Carseland (data source: Archived Hydrometric Data, Water Survey of Canada 2009)...... 34

Figure 4.4 Daily flows in the headwork irrigation canals of WID, BIRD and EID in 2007 and 2008...... 36

Figure 4.5 δ2H and δ18O values of waters from the Bow River and its tributaries shown together with the LEL (Ferguson et al. 2007), SGWL (Cheung 2009) and LMWL (Peng 2004)...... 37

Figure 4.6 δ2H and δ18O values of waters from tributaries discharging into the Bow River on the prairies...... 38

Figure 4.7 δ2H and δ18O values of waters from Calgary’s WWTPs (red), instream wastewater plume at 482 km (green), and upstream of the WWTPs (blue)...... 39

Figure 4.8 δ18O and δ2H values of the Bow River versus flow distance. Data points from waters sampled during the irrigation season are shown in open circles whereas those of the baseflow and peakflow periods are shown in solid squares.... 40

Figure 4.9 Seasonal variations in the δ18O and δ2H values of the Bow River water from Lake Louise (0 km) to Ronalane (571 km). Shaded areas indicate the irrigation periods when the isotopic compositions of waters at Ronalane were noticeably higher than the rest of the Bow River...... 42

Figure 4.10 Dual isotope diagram for the Bow River water from June to November in 2007 and from April to July in 2008...... 44

Figure 4.11 Variations in a) δ18O and b) δ2H values with flows in different reaches of the Bow River. Regression lines in red are for the peak flow period in June 2008 and the label in red are distances in km from Lake Louise (0 km)...... 46

Figure 5.1 Flow-weighted average TDS, annual solute loads and annual total discharges in the Bow River along the flow path from Lake Louise (0 km) to Ronalane (571km)...... 55

Figure 5.2 Mass balance flow chart showing annual total solute loads in kt from Lake Louise (0 km) to Ronalane (571 km) along the Bow River. Major inputs along the river include the WWTPs and the Elbow and Highwood Rivers. Major withdrawals occur at the main canal of the WID, BRID and EID...... 57

Figure 5.3 Relationships between the total annual solute loads and the total annual discharges in the Bow River in 2007 and 2008 at various sites from the headwaters at Lake Louise (0 km) to near the mouth at Ronalane (571 km). The open squares are values from 2007 and the solid squares are values from 2008...... 59

xi Figure 5.4 Variations in the annual mass loads of the six major ions along the Bow River expressed in giga (x109) mole-equivalent. Extrapolation (dotted lines) represents anticipated trends based on the observation that concentrations-flow relationships between Carseland and Cluny are similar...... 61

Figure 5.5 Calcite and gypsum solubility fields for the Bow River waters at 1 atmosphere pressure and within 0-27oC, the maximum temperature range of the river waters (sample calculation for calcite solubility is shown in Appendix C). .... 64

Figure 5.6 Scatter plots showing the various combinations of cations against anions for the Bow River water and their correlations with respect to the 1:1 charge equivalence line...... 66

Figure 5.7 Durov diagram showing the range of anion and cation compositions (eq%) of waters from the Bow River, the prairie tributaries and the treated wastewater effluents from Calgary...... 70

Figure 5.8 Chemical separation of various water types in the Bow River Basin showing plots of a) Ca/Mg ratios against HCO3/SO4 ratios and b) Na/Ca ratios against HCO3/SO4 ratios for the Bow River water, wastewater and tributary waters. All ratio values were calculated from ionic concentrations in units of meq/L...... 72

Figure 5.9 Plot of HCO3/SO4 ratios versus TDS for the tributary waters of the three irrigation districts – WID, BRID and EID – east of Calgary. All ratio values were calculated from ionic concentrations in units of meq/L...... 73

Figure 5.10 Monthly variations of ion ratios for a) Cl/SO4, b) Na/Ca, c) HCO3/SO4 and d) Ca/Mg in the Bow River water. The shaded area in grey indicates baseflow periods. All ratio values were calculated from ionic concentrations in units of meq/L...... 76

Figure 6.1 SO4 concentration-flow relationships along the Bow River from Lake Louise (0 km) to Ronalane (571 km)...... 83

Figure 6.2 Plots for a) SO4 concentrations along the length of the Bow River from Lake Louise (0 km) to Ronalane (571 km) and b) variations in the monthly SO4 concentrations...... 85

Figure 6.3 a) The total annual mass loads of SO4 along the Bow River from Lake Louise (0 km) to Ronalane (571 km) and b) the SO4/Cl mole equivalent ratios downstream of Calgary’s WWTPs...... 87

Figure 6.4 Mass balance flow chart showing annual total SO4 loads in kt from Lake Louise (0 km) to Ronalane (571 km) along the Bow River. Major inputs along the river include the WWTPs and the Elbow and Highwood Rivers. Major withdrawals occur at the main canal of the WID, BRID and EID...... 89

xii 18 34 Figure 6.5 δ OSO4 versus δ SSO4 values for various SO4 sources in the environment (after Krouse and Mayer 2000) and data points in the box are from water samples in the Bow River and it tributaries...... 90

18 34 Figure 6.6 Dual isotope diagram showing the δ OSO4 and δ SSO4 values for samples from the Highwood River and the prairie tributaries...... 93

18 34 Figure 6.7 Plot showing δ OSO4 values versus δ SSO4 values of the Bow River water from Lake Louise (0 km) to Ronalane (571 km) and the wastewaters at Calgary...... 94

18 34 Figure 6.8 Plot showing δ OSO4 values against δ SSO4 values of the Bow River water during peakflow and non-peakflow periods...... 95

34 18 Figure 6.9 Variations in the δ SSO4 (a-c) and δ OSO4 (d-f) values with flow distances along the Bow River from Lake Louise (0 km) to Ronalane (571 km) throughout the summer and fall of 2007 and the spring of 2008...... 96

34 Figure 6.10 Plot showing the SO4 flux-weighted average δ SSO4 values versus the annual mass loads of SO4 in the Bow River from Lake Louise (0 km) to Ronalane (571 km)...... 97

18 18 Figure 6.11 Plot of δ OSO4 against δ OH2O values for the Bow River and its prairie tributaries. The sulfide oxidation field within the black solid lines is derived based on experimental results from Taylor et al. (1984) and by Van Stempvoort and Krouse (1994). The dashed red line is derived from recent experimental results from Balci et al. (2007) showing the effect of H2O-oxygen incorporation at 87% and O2-oxygen at 13%...... 100

34 18 Figure 6.12 SO4 flux weighted average δ SSO4 and δ OSO4 values for the Bow River at Lake Louise (0 km), Canmore (99 km), Cochrane (179 km), Calgary above WWTP (212 km) and Carseland (302 km). The range of isotopic values for the combined averages of the prairie tributaries were determined based on the known values of the wastewater...... 102

Figure 7.1 NO3 concentrations of Bow River waters sampled between the headwaters at Lake Louise (0 km) and near the mouth at Ronalane (571 km) from a) early peak flow recession (Jun07) to the ice-covered baseflow conditions (Nov07), and b) from ice-covered baseflow (Nov07) to summer peakflows (Jul08)...... 109

Figure 7.2 Scatter plot showing NO3 concentration-flow relationships upstream of Calgary’s WWTPs (0-212 km) during non-peakflow and peak flow periods. Regression equations were fitted for the month of June in 2007 and 2008...... 112

Figure 7.3 The Bow River NO3 concentration-flow relationships at Lake Louise (0 km) and Cochrane (179 km) during rising flow periods (a and c) and similarly during receding flow periods (b and d)...... 114

xiii Figure 7.4 Inverse relationships between NO3 concentrations and flows at a) Carseland (302 km) and Cluny (378 km) and b) below the Bassano Dam at Bow City (482 km) and Ronalane (571 km)...... 115

Figure 7.5 Diagrams of monthly NO3 and NH4 fluxes in kt/month for the two wastewater treatment plants, a) Bonnybrook and b) Fish Creek in Calgary (data provided by Water Quality Services, the City of Calgary)...... 117

Figure 7.6 a) Time series hydrograph of the Crowfoot Creek (Alberta Environment 2009) and NO3 concentrations of the Crowfoot Creek, E1717 and E1716 b) Time series hydrograph of the 12 Mile Creek (Alberta Environment 2009) and NO3 concentrations of E1616, B1516 and 12 Mile Creek...... 118

Figure 7.7 a) Annual mass loads of NO3 in the Bow River from Lake Louise (0 km) to Ronalane (571 km). Inputs from WWTPs in Calgary and withdrawals by WID, BRID and EID are shown. b) NO3/Cl mole equivalent ratios downstream of Calgary’s WWTPs...... 122

Figure 7.8 Mass balance flow chart showing annual total NO3 loads in kt from Lake Louise (0 km) to Ronalane (571 km) along the Bow River. Major inputs along the river include the WWTPs and the Elbow and Highwood Rivers. Major withdrawals occur at the main canal of the WID, BRID and EID...... 123

18 15 Figure 7.9 Dual isotope diagram showing the δ ONO3 and δ NNO3 values of samples from the Bow River, its tributaries, wastewater effluents and the typical isotopic ranges of the various NO3 sources in the environment. The arrows indicate changes in isotopic compositions as a result of denitrification (after Kendall et al. 2007; Kool et al. 2007; Böttcher et al. 1990)...... 125

15 Figure 7.10 Plots for the Highwood River showing a) δ NNO3 vs. NO3 18 concentrations and b) the δ ONO3 versus NO3 concentrations...... 130

Figure 7.11 Plots for the Highwood River and the small prairie tributaries showing 15 18 15 18 a) δ NNO3 versus δ ONO3 b) δ NNO3 versus NO3 concentrations and c) δ ONO3 versus NO3 concentrations...... 131

18 15 Figure 7.12 Plot of δ ONO3 versus δ NNO3 values for waters of the Bow River from headwater to mouth. Also shown is the isotopic composition of NO3 in the wastewater effluent from Calgary’s WWTPs...... 133

15 18 Figure 7.13 Average δ NNO3 and δ ONO3 values of the Bow River along its flow path between Lake Louise (0 km) and Ronalane (571 km)...... 134

15 18 Figure 7.14 a) δ NNO3-NO3 concentration and b) δ ONO3-NO3 concentration relationships for the Bow River during baseflow periods from August 2007 April 2008...... 136

xiv 18 15 Figure 7.15 Dual isotope diagram showing δ ONO3 and δ NNO3 values produced by mixing variable amounts of wastewater derived NO3 with the Bow River NO3 derived from forest soils (0km). The red arrow shows the extent of isotopic shift in wastewater derived NO3 under the influence of nitrification of wastewater NH4 sources (see Table 7.3; Section 7.7.2 for derivation of the wastewater nitrification trend) ...... 138

18 15 Figure 7.16 δ ONO3-δ NNO3 diagram showing variable ranges of wastewater contributions to the Bow River downstream of Calgary during the snowmelt and rainfall periods in May and June...... 139

Figure 7.17 Average isotopic compositions of NO3 in the Bow River from Lake 18 15 Louise to Ronalane (0-571 km) along the δ ONO3-δ NNO3 curve linking the two end member sources represented by the isotopic compositions of NO3 at Lake Louise and NO3 from the WWTPs (red squares). Samples from downstream of the Bassano Dam during the second half of the irrigation season (July- September) were plotted separately to show the deviations from the general trend...... 140

15 18 Figure 7.18 The relationships for a) δ NNO3 and NO3 concentrations and b) δ ONO3 and NO3 concentrations downstream of the Bassano Dam (482-571 km). The equations were derived for baseflow samples obtained from August 2007 to April 2008...... 141

xv List of Symbols, Abbreviations and Nomenclature Symbol Definition

WWTP Wastewater Treatment Plant TPBB Bonnybrook Wastewater Treatment Plant TPFC Fish Creek Wastewater Treatment Plant WID Western Irrigation District BRID Bow River Irrigation District EID Eastern Irrigation District BRB Bow River Basin SSRB South Saskatchewan River Basin CF-IRMS Continuous Flow Isotope Ratio Mass Spectrometry WHO World Health Organization USEPA U.S. Environmental Protection Agency USGS U.S. Geological Survey AENV Alberta Environment AAFRD Alberta Agriculture, Food and Rural Development HCL Hydrogeological Consultants Ltd. IFN Instream Flow Need TDS Total Dissolved Solids DO Dissolved Oxygen EC Electrical Conductivity DNRA Dissimilatory Reduction of Nitrate to Ammonium Anammox Anaerobic Ammonium Oxidation Masl Meters above sea level K kilo - one thousand (103) M Mega - one million (106) G Giga - one billion (109) Μ micro (10-6) Ppm parts per million (10-6) ‰ per mil (parts per thousand) δ Delta LMWL Local Meteoric Water Line LEL Local Evaporation Line V-SMOW Vienna – Standard Mean Ocean Water V-CDT Vienna – Canyon Diablo Troilite

xvi

CHAPTER 1: INTRODUCTION

Surface water and groundwater together constitute less than one percent of the global water supply that the world’s population depends on for consumption and use (Gleick 1996). Of the vast amount of water on Earth, only less than 0.01% is freshwater accessible in rivers and lakes (Gleick 1996; Smol 2002). Freshwater resources are diminishing rapidly due to human population growth, urbanization and overexploitation leading to severe deforestation and wetland lost in the 20th century (Smol 2002). Contamination from anthropogenic activities degrades the quality of water resources in many regions of the Earth. In fact, water shortages and polluted freshwater supplies are confronted by people worldwide (Hoekstra 2006), and concerns stemming from these issues have led to the realization that watershed management and ecosystem protection is the ultimate long-term solution to water conservation (Smol 2002).

The Bow River flowing through Calgary in southern Alberta is a major tributary to the South Saskatchewan River. The South Saskatchewan River Basin (SSRB) is comprised of three sub-basins including the Red Deer, the Bow and the Oldman River Basins (see Figure 3.1). Urbanization has the potential to significantly degrade the water quality in the Bow River since wastewater effluents from major municipalities are discharged into it directly. The Bonnybrook Wastewater Treatment Plant (TPBB) and the Fish Creek Wastewater Treatment Plant (TPFC) in Calgary are two major point sources of wastewater discharge to the Bow River. The Pine Creek Wastewater Treatment Plant, operational as of May 2010 (City of Calgary 2009, 2010), was recently built in response to Calgary’s expanding population and urban development.

Downstream of Calgary, land use activities are mainly agricultural. In addition to cultivated lands, cattle pastures and feedlots are also common. The southern Albertan prairies east of Calgary is divided into three irrigation districts: the Western Irrigation District (WID), the Bow River Irrigation District (BRID) and the Eastern Irrigation District (EID) (locations shown in Figure 3.2). Of the total annually licensed water

allocation (2.77x1012 L) from the Bow River, the amount withdrawn for irrigation (77%) was the highest followed by municipal usage (17%) (Bow River Basin Council 2005). The government of Alberta has recognized that water supply in the province has become increasingly unpredictable and strained due to factors such as population growth, droughts, and agricultural and industrial developments. In response to the growing concern over potential water crisis in the future, a series of plans were outlined in Water for Life: Alberta’s Strategy for Sustainability, and South Saskatchewan River Basin Water Management Plan (Phase I and II) (Alberta Environment 2002, 2003). The government of Alberta announced its commitment to ensuring a strong economy without jeopardizing the freshwater resources of the SSRB, and improving its aquatic ecosystem management approach (Alberta Environment 2006).

In short, the current strategy applies the concept of instream flow need (IFN) to help regulate water usage and distribution within the SSRB and minimize impacts from economic developments. Temperature, dissolved oxygen, and concentration of ammonia are the primary criteria of water quality IFN determination (Clipperton et al. 2003). Temperature and dissolved oxygen are critical for fishery protection and organic waste assimilation, and ammonia is a nutrient source that can have highly toxic effect on aquatic organisms, especially on freshwater fish (World Health Organization 1986).

The most up to date information published by Alberta Environment (Figure 1.1) reveals that the current IFN determination for protecting ecosystem health (a) and water quality (b) is incomplete for the Bow River downstream of the Bassano Dam as well as after its confluence with the Oldman River (red line). Furthermore, spring and fall were not included in the IFN determination in Figure 1.1 (Clipperton et al. 2003). Although the headwater reaches of the SSRB are well monitored by IFN modeling, a similar effort for the final reach of the Bow River, where mixing of irrigation return flows and wastewater effluents occurs, is clearly lacking. As a major tributary to the South Saskatchewan River in a semi-arid environment, the fact that the Bow River is stressed from rapidly

increasing anthropogenic activities (Alberta Economic Development Authority 2008; Alberta Environment 2002, 2003) is concerning.

Figure 1.1 Maps showing reach-specific data availability for IFN determinations in the South Saskatchewan River Basin modeled for (a) integrated ecosystem and (b) water quality (after Clipperton et al. 2003).

Project Rationale Aquatic ecosystems are vulnerable to elevated nutrient loads (Smol 2002; World Health Organization 1978) from wastewater effluents (point source) and agricultural return flows (non-point source). Primary productivity, once stimulated, may significantly reduce dissolved oxygen levels in the river during respiration and harm the aquatic organisms (Smol 2002). Given that non-point sources of nutrients are difficult to monitor and control, riverine nutrient loads can potentially increase to unexpected levels. An understanding about the fate and transport of major anthropogenic nutrients is therefore, necessary for effective and sustainable watershed management.

The Bow River is an important freshwater resource in southern Alberta; however, urban wastewater discharges and agricultural return flows can potentially degrade the water

quality of the Bow River by elevating riverine SO4 and NO3 concentrations. Releases of

SO4 and NO3 to the SSRB due to urbanization and agricultural activities have been attracting attention (Rock and Mayer 2004, 2006 and 2009). A recent isotopic study by

Rock and Mayer (2009) showed that SO4 loads from an artificially drained sub-basin of the Oldman River Basin (ORB) south of the BRB exceeded that of a naturally drained area by an order of magnitude. This anomaly was attributed to tillage of agricultural lands, which can facilitate enhanced sulfide oxidation in the prairie tills, and thereby

elevating SO4 levels in the lower reaches of the ORB (Rock and Mayer 2009). In

addition to SO4, Rock and Mayer (2006) found that manure derived NO3 fluxes were controlled hydrologically by agricultural return flows with noticeable impact on the

surface waters of the ORB. For the Bow River, wastewater derived NO3 from urban centres is of great concern given that serious eutrophication had occurred in the past (Ongley and Blachford 1982; Hamilton 1982) and studies conducted after upgrading of Calgary’s WWTPs suggested that biomass growth in the Bow River is N-limited (Sosiak 2002; Hogberg 2004). As ongoing urban and agricultural impacts on the Bow River are

expected, assessment of sources and processes affecting riverine SO4 and NO3 is important for better management practice.

This project was initiated under the premise that stable isotope techniques can be

effectively applied to separate and trace the major sources of SO4 and NO3 in the Bow River. Conventionally, concentration, flow and flux data are analyzed but the usefulness of these data in elucidating riverine solute sources is often limited. Given that fractionation of isotopes by various physical, chemical and biological processes often yield characteristic isotopic signatures, isotopic analyses have been frequently used to help identify and trace pollutants in various environments (Clark and Fritz 1997). Numerous studies have utilized isotopic techniques to evaluate the sources and the fate of

SO4 and NO3 in freshwater water environments (e.g. Aravena et al. 1993; Rock and Mayer 2002, 2004, 2006, 2009; Vitòria et al. 2004; Astrid et al. 2008; Ohte et al. 2010). The application of isotopic techniques has been proven to be effective in source differentiation and apportionment.

Project Objective The objective of this study was to determine the impact of urban and agricultural practices on the water quality of the Bow River by evaluating the major ion geochemistry

of the river and tracing the sources and fate of riverine SO4 and NO3 using integrated hydrometric, chemical and isotopic techniques.

Chapter Outline Chapter 1 introduces the project rationale and objective. General background information on the climate, physiography, geology, soils and groundwater chemistry of southern Alberta is provided in Chapter 2. Fieldwork, laboratory and computation methods are described in Chapter 3, which is followed by results and discussions in the

subsequent four chapters. In Chapter 4, the isotopic composition of H2O was evaluated to verify sources of river flows and to determine if effects of urban and agricultural activities can be discerned using δ2H and δ18O values. Chapter 5 discusses the major ion chemistry of the Bow River. Chapter 6 and 7 apply isotopic techniques to identify and

apportion sources of SO4 and NO3 in the Bow River. Finally, Chapter 8 summarizes the major findings of this study and comments on the direction of future research.

CHAPTER 2: BACKGROUND

2.1 The Bow River Basin Melting of snowpack and glacial ice in the Rocky Mountains east of the Continental Divide is an important constituent of headwater flows of the Bow River Basin (Bow River Basin Council 2005). The Bow River flows out of Bow Lake in a southeasterly direction through Lake Louise, Banff, and Canmore and eventually exits the Rocky Mountains at the eastern edge of the Rocky Mountain Foothills near Cochrane. On the prairies, the Bow River gradually widens and decreases in gradient (Bow River Basin Council 2005) while meandering through the river valley until its confluence with the Oldman River. As a major tributary to the South Saskatchewan River, which eventually drains into the Hudson Bay, the Bow River contributes approximately 43% of the total 9500 million m3 of discharge per year (Bow River Basin Council 2005).

2.2 The Climate of Southern Alberta The sub-humid to semiarid climate of the Canadian Rocky Mountain is characterized by long cold winters with snow covering the ground from November to March. Partial to complete melting of snowpacks covering the low altitude ranges and foothills occurs typically in April, but snowmelt in the high altitude ranges generally starts one month later in May. December and January in the Rocky Mountains are the coldest months with an average daily temperature of -14oC whereas July and August, the warmest months, have an average daily temperature of 12oC (Environment Canada 2010). The prairie plains of southern Alberta are characterized by sub-humid to semi-arid climates influenced by cold Arctic air masses in the winter and Continental and Pacific air masses in the summer (Alberta Environment 2004; Government of Alberta 2009). Most of the region is frequently encompassed by winter low-pressure systems where high wind is generated by steep temperature and pressure gradients. The mean daily temperature on the prairies in January is -11oC in contrast to 18oC in July (Environment Canada 2010).

From the mountains to the prairies in the winter, southern Alberta is occasionally affected by the warm and dry winds (Chinook) from the west. The Chinook can cause a large temperature increase of up to 30oC and a humidity decrease of over 40% (Environment Canada 2010). Annual precipitation decreases from west to east with a high proportion falling as snow in the mountains and as rainfalls on the prairies (see also Section 4.2; Chapter 4). Drastic seasonality and temperature fluctuations are key climatic features that affect many natural processes directly. More importantly, high evaporation on the prairies causes loss of water from the soil zones and open water bodies (Last and Ginn 2005). Prevalent winds from the west and southwest with a moderate to high speed can further enhance evaporation along their path. The average precipitation of the Rocky Mountains (500-1000 mm/yr) exceeds evapotranspiriation (~400 mm/yr); however, most of the province is in the interior plains where evapotranspiration (~400 mm/yr) is higher than precipitation (300-400 mm/yr) (Atlas of Canada 2009; Alberta Environment 2004). In fact, moisture deficiency is a critical factor responsible for the high natural salinity of the prairie plains throughout western Canada (Last and Ginn 2005).

2.3 The Physiographic Regions The physiography of southern Alberta is divided into five major regions. From west to east, they are the Rocky Mountains (M), the Rocky Mountain Foothills (L), the Southern Alberta Uplands (J), the Western Alberta Plains (G) and the Eastern Alberta Plains (F) (Figure 2.1a) (Pettapiece 1986). The prairie plains are characterized by hummocky to gently rolling topography with numerous upland areas and terraced valleys (Pettapiece 1986) carved out by erosion from glacier melt waters on top of pre-glacial bedrock (Stalker 1961). On the prairies between Calgary and the mouth of the Bow River, the physiographic sub-regions (sections) consist of the Drumheller Uplands (G5), the Blackfoot Uplands (G6) and the Cooking Lake Uplands (F16) that surround the Blackfoot Plain (F9) through which the Bow River flows (Figure 2.1b) (Pettapiece 1986). On the Eastern Alberta Plains (east of the Bassano Dam), the entire drainage area is covered by the Sillivan Lake Plains (F6) (Figure 2.1b) (Pettapiece 1986). On the Western

Alberta Plain (G), the Bow River is bounded by the Olds Plain (G2) to the north and the Southwest Plains to the south (Figure 2.1b) (Pettapiece 1986).

2.4 Geology In the Bow River Basin, the area from the Continental Divide to about 50 km downstream of Lake Louise belongs to the Main Ranges of the Rocky Mountain where the geology is dominated by the Late Precambrian Miette Group (1780-730 Ma) and Lower Cambrian Gog Group (570 Ma). The Precambrian and Cambrian formations of the Main Ranges are sedimentary strata deposited in deltaic or shallow sea environments (Charlesworth et al. 1967; Hein and McMechan 1994; Hamilton et al. 1999) (Figure 2.2). The Upper Miette Group (730-770 Ma) consists predominantly of metamorphosed coarse-grained clastic sandstones and pelitic shale, and the Lower Miette Group (1780 1570) contains a mixture of fine-grained clastic and carbonate rocks. These sedimentary strata characterizing the geological formations of the Main Ranges are among the oldest in southern Alberta. The carbonate bedrock of the Main Ranges between Lake Louise and Banff (0-65 km) is mainly of Lower Paleozoic age (Figure 2.2) and includes middle and upper Cambrian limestone, Ordovician siliceous dolomite and quartzite, and Silurian dolomite (Hamilton et al. 1999).

The Front Ranges of the Rocky Mountains, situated approximately between the Pipestone Thrust to the west and the McConnell Thrust to the east, are largely characterized by Upper Paleozoic to Lower Cretaceous limestone, dolomitized limestone and dolostone (Figure 2.2) (Hamilton et al. 1999). There is however, mineralogical differences between the Main and the Front Ranges of the Rocky Mountains. Abundant gypsum and anhydrite deposits occur in the Paleozoic and Triassic formations of the Front Ranges (Hamilton et al. 1999) with the Devonian carbonates being a notable example given the widespread and abundant evaporite minerals formed in an ancient embayment during this period (Mossop and Shetsen 1994). Anhydrite and gypsum are important evaporite deposits and they are commonly found in the geological formations of the Front Ranges between Banff and Morley (65-140 km). Anhydrite typically occurs in the Upper Paleozoic formation whereas gypsum is usually associated with the younger Triassic rocks (Hamilton et al. 1999).

The rest of the Bow River Basin east of the Rocky Mountains is underlain by clastic sedimentary sequences consisting of mainly the Horseshoe Canyon, Scollard, Paskapoo, and Porcupine Hills Formations (Figure 2.2). These formations were deposited between the Cretaceous and Paleocene periods. The Bearpaw Formation on the Eastern Alberta Plain represents the last marine sequence associated with the Western Interior Seaway (Catuneau et al. 1997; Hartman and Kirkland 2002). Uplift of the Rocky Mountains at the end of the Cretaceous forced the seaway to retreat; therefore, formations overlying the Bearpaw on the Western Alberta Plain are terrestrial and fresh-water deposits. The Horseshoe Canyon Formation, the transition between marine and terrestrial depositional setting, is the only exception containing mixed sequences of brackish water marginal marine to fresh water fluvial and lacustrine deposits (Mossop and Shetsen 1994). The Oldman and Foremost Formations together constitute the Belly River Formation, a marine regression phase with the lower portion (Foremost Formation) deposited in coastal to shallow-marine settings (Mossop and Shetsen 1994).

On the prairies atop the thick (up to 5000 m) horizontal Phanerozoic sedimentary bedrock (Klassen 1989; Ricketts 1989; Mossop and Shetsen 1994) are multiple glacial sediments deposited during the Pleistocene (Bird 1972; Ricketts 1989; Mossop and Shetsen 1994). The surficial deposits are mainly tills with interspersed units of clay, silt, sand and gravel, and they are generally tens to hundreds of meters thick (Ricketts 1989; Mossop and Shetsen 1994). Meltwater from retreating glaciers created numerous channels and spillways in the glacial sediments. The bedrock surface was strongly modified by glacial erosion prior to the deposition of Quaternary sediments up to 300 m thick (Klassen 1989). Underneath the Cretaceous bedrocks of sand and shale sequences (Ricketts 1989; Mossop and Shetsen 1994) are series of stacked soluble Paleozoic carbonate-evaporites sequences. Dissolution of Paleozoic evaporites by groundwater created abundant collapse structures in the local bedrock (Mossop and Shetsen 1994; Last and Ginn 2005), causing modification of the bedrock topography as well as the overlying physiographic expressions. In particular, this geological feature dominates the Williston Basin in

11 southern Saskatchewan whose western limit extends into Alberta to the border with the Alberta Basin near the Bow Island Arch (Mossop and Shetsen 1994).

2.5 Soil Types Five major soil types occur in southern Alberta and the Bow River Basin. The Main Ranges from the Continental Divide to Lake Louise (0 km) is dominated by exposed

bedrock surfaces on steep slopes with no significant soil development. The brunisolic soils in the Front Ranges are in the early stage of soil development on unweathered parent materials (regosolic soils) (Agriculture and Agri-Food Canada 1998). In contrast, Luvisisolic soils in the Rocky Mountains are matured forest soils derived after thousands of years of weathering on loamy tills or clayey lacustrine deposits (Agriculture and Agri- Food Canada 1998). This soil type dominates the forested parts of the Rocky Mountain from the Front Ranges near Banff (65 km) to the Foothills at Cochrane (179 km) (Figure 2.3).

Figure 2.3 Soil types in southern Alberta and sampling sites along the Bow River in distances (km) with respect to Lake Louise (compiled in ARC-GIS).

The prairie grasslands are dominated by chernozemic soils with high inputs of organic matter forming the top humus layer (A-horizon). Decomposition of organic matter and leaching of organic acid led to mineral weathering, and dissolution of the primary carbonates and evaporites in the parent material. Dissolved minerals transported by

13 downward movements of infiltrating water result in a well-leached horizon (B-horizon) and a mineralized (re-precipitated secondary carbonate and salt) layer on top of the C- horizon beneath it (Agriculture and Agri-Food Canada 1998). The black, dark brown and brown chernozemic soils are distinguishable from the properties of the humus horizon. These soil type discrepancies arise from varied developmental conditions under different climatic regimes. The darker the colour is, the thicker the organic layer and the higher the organic content. Solonetzic soils are characterized by high sodium levels in the well- leached B-horizon and are typically associated with saline and clay-rich parent materials. Although this type of soil generally occurs in small patches throughout the prairies (Government of Alberta 2005), its distribution is concentrated towards central Alberta (Figure 2.3). Within the Bow River Basin, solonetzic soils are widely distributed within the Eastern Irrigation District, the final reach of the Bow River (Figure 2.3).

2.6 Groundwater Chemistry on the Prairies Geology influences the chemistry of groundwater and surface waters on the prairies. Evaporite dissolution is the attributed cause of salinity in the drainage systems of the Western Glaciated Plains according to studies by Murphy (1996), Grossman and Hartford (1968), Last (1989, 1987) and Last and Ginn (2005). The present-day groundwater systems are not only affected by the regional geology (Christiansen 1979), much of the ancient dendritic drainage patterns from the Quaternary Period are mirrored by where the present-day tributaries on the prairies occur (Stalker 1961; Farvolden et al. 1963). The prairie tributaries, although intermittent in flow, are considered important groundwater outcrops (Meyboom 1967) on the prairies. In addition, aridity coupled with the low permeability of the clayey tills created extensive closed drainage basins throughout eastern and central Alberta (Last 1989; Last and Ginn 2005). Early hydrochemical investigation by Meyboom (1967) (Figure 2.4) showed that although shallow groundwaters in Alberta are predominantly Na-HCO3 type (green area), Ca-Mg-SO4 water (yellow area) were present in isolated regions north of Calgary as well as along a region between Lethbridge of the Oldman River Basin and the Blackfoot Plain of the Bow River Basin.

Groundwater compositions in the Interior Plains of Western Canada were classified into three major types. Most of the groundwater in unconsolidated surficial aquifers is Ca

Mg-HCO3 type water with low to moderate salinity and contains less than 3000 ppm TDS (Johnson and Johnson 1992; Last and Ginn 2005; HCL 2003, 2007; Cheung and Mayer 2009). Shallow groundwaters in regions with high aridity were dominated by Ca-Mg

SO4 type water and bedrock aquifers of the Upper Cretaceous and younger are mainly of

Na-HCO3 type (Johnson and Johnson 1992; HCL 2003, 2007; Last and Ginn 2005; Cheung and Mayer 2009). Deep groundwaters in the Paleozoic and Cenozoic bedrocks containing TDS as high as 300000 ppm (Johnson and Johnson 1992; HCL 2003, 2007; Last and Ginn 2005) are the most saline formation waters of Na-Cl type.

Figure 2.4 Hydrochemical map of shallow bedrock aquifers in the Interior Plains of Canada showing regions of Na-HCO3 (green), Ca-Mg-SO4 (yellow), Mg-Ca-HCO3 (blue) and Na-SO4 (light yellow) waters. Contours in blue are baseflow indexes in glm (gallon per minute per square miles) (modified after Meyboom 1967).

CHAPTER 3: SAMPLING AND ANALYTICAL METHODS

3.1 Fieldwork Overview Monthly sampling of the Bow River was conducted from June 2007 to July 2008 and the prairie tributaries were sampled from September 2007 to July 2008. The prairie tributaries were sampled montly from September 2007 to July 2008. Treated wastewater effluents from the Bonnybrook and the Fish Creek Wastewater Treatment Plants in Calgary, and the wastewater plume in the Bow River were sampled between April and July 2008. Fieldwork was paused during the winter months from December to March as ice conditions in the river were not suitable for sampling.

Analyses derived from a water sample collected at a single sampling point in the river were assumed representative of the river’s chemical and isotopic compositions at that location. Although integrated sampling through different depths and at different points across the width of the river is ideal, multipoint sampling is time-consuming, expensive and logistically impractical for this study. In surface water quality studies, samples are commonly taken in the river where conditions for uniform flow and good mixing occur (Stednick 1991; USGS 2006).

Sampling Sites A summary of all the sampling sites with their codes and abbreviations is detailed in Appendix A. The main sampling locations along the Bow River include Lake Louise (0 km), Canmore (99 km), Cochrane (179 km), Calgary upstream of WWTPs at the Bowness Park (212 km), Calgary below WWTPs at the Fish Creek Park (248 km), Carseland (302 km), Cluny (378 km), Bow City (482 km), Scandia (513 km) and Ronalane (571 km) (Figure 3.1). The Highwood River, the only major tributary downstream of Calgary, was sampled near its confluence with the Bow River at 272 km, which is 30 km upstream of Carseland (not shown in Figure 3.1).

Dist. (km) Locations 0 Lake Louise 99 Canmore 179 Cochrane 212 Calgary at Bowness Park (above WWTPs) 248 Calgary at Fish Creek Park (below WWTPs) 302 Carseland 378 Cluny 482 Bow City 513 Scandia 571 Ronalane

Nine intermittent tributaries throughout the irrigation districts were chosen based on maps provided by Alberta Agriculture, Food and Rural Development (AAFRD). Codes were assigned to help identify sampling sites on maps. Letter prefixes were used to represent the irrigation districts - WID (W), BRID (B) or EID (E), and the two pairs of digits that follow the prefixes represent the township (first pair) and the range (second

17 pair) numbers. For example, B1416 is sampled in BRID south of the Bow River within township 14 and range 16. The Crowfoot Creek, B1516, New West Coulee (B1416), 12 Mile Creek (E1413) and B1212 correspond to the AAFRD monitoring sites: W-R2, BR R1, BR-R2, E-R5 and BR-R5 respectively (Figure 3.2). The prairie tributaries were sampled close to their confluences with the Bow River. Locations of the main irrigation canals to WID, BRID and EID are shown in Figure 3.2. The Crowfoot Creek (CF Ck.) is the final outlet of WID and the only WID tributary sampled. The final outlets of BIRD and EID are B1212 and E1413 respectively (Figure 3.2).

In Calgary, treated wastewater effluents from the Bonnybrook Wastewater Treatment Plant (TPBB) and the Fish Creek Wastewater Treatment Plant (TPFC) were sampled. TPBB is the largest wastewater treatment plant (WWTP), capable of handling 500ML/day of sewage, whereas TPFC is only capable of handling 72ML/day (City of Calgary 2008). The instream wastewater plume in Calgary was sampled along the Bow River in Calgary at five locations between 230 and 250 km (see Appendix A).

Sample Collection and Preparation Temperature, pH, specific conductivity and dissolved oxygen levels were measured instream with a YSI probe. Samples for dissolved inorganic carbon (DIC) concentrations and 13C/12C ratio measurements were collected in air-tight narrow mouth glass bottles. Samples for other chemical and isotopic analyses were collected in polyethylene Nalgene bottles. After grab samples for isotopic analyses on DIC and H2O were collected in the river, a bulk volume of river water was taken ashore and filtered using a pressurized gas filtration device fitted with 0.45µm membrane filter paper. Samples from June 2008 were collected along the riverbank because the flow condition was unsafe for wading. Samples from late November 2007 were collected below thick ice covers from near bank locations or midstream when conditions were deemed safe to do so.

Samples for cation (Ca, Mg, Na, and K) analyses were acidified with 70% analytical grade nitric acid to pH<2. The NH4 samples were acidified with analytical grade sulphuric acid to pH<2. No chemical preservative was added to anion (SO4, Cl and NO3) 34 18 samples. lL of water for δ S and δ O measurements of SO4 was preserved by adding

10ml of 10% (w/v) BaCl2 solution to precipitate BaSO4 after acidification to pH 3-4. At the laboratory, the BaSO4 precipitates were extracted via vacuum filtration and air-dried. 15 18 Samples for δ NNO3 and δ ONO3 analyses were frozen and stored in a freezer upon return to the laboratory while samples for chemical analyses were stored cool at 4oC.

3.2 Laboratory Analyses Major Ion Concentrations Bicarbonate concentrations were determined via acid titration. Concentrations of the other major ions Ca, Mg, Na, K, SO4 and Cl were determined using the ICS-1000 Dionex Ion Chromatography System at the Environmental Science Laboratory at the University of Calgary. The measurement uncertainty was less than ±5% of the reported concentrations and is reflected in the excellent electrical charge balance relationship 2 (r =0.9986) in Figure 3.3. NO3 and NH4 concentrations were determined by the Biogeochemistry Laboratory at the State University of New York (SUNY) using an ion chromatography system (EPA600/4-87/062) and the automated Phenate EPA350.1 system respectively. The reported method detection limits (MDL) were 0.04 mg/l for

NO3 and 0.0068 mg/L for NH4.

40 1:1

2 30 y=0.97x+0.26 (r =0.9986, n=189)

25 +3.9% 20 -4.9% 15

5 Total Cation Concentration (meq/L) (meq/L) Concentration Cation Total -6.1% -9.9% 0 0 5 10 15 20 25 30 35 40 45

Total Anion Concentration (meq/L)

Figure 3.3 Electrical charge balance relationship of the major ions.

Stable Isotope Ratio Measurements Samples for stable isotope ratio measurements were analyzed at the Stable Isotope Laboratory at the University of Calgary. Isotopic analyses involve abundance measurements of heavy and light isotopes by mass spectrometry. The analyses included 2 1 18 16 34 32 18 16 15 14 isotope ratios of H/ H and O/ O of H2O, S/ S and O/ O of SO4, N/ N and

18 16 15 14 13 12 O/ O of NO3, N/ N of NH4, and C/ C ratios of HCO3. The isotope ratios of the less abundant heavy isotopes over the more abundant light isotopes are corrected with respect to a reference material, and the final isotopic value is reported in the delta (δ) notation with a unit of per mil (‰) according to the expression:

δ [‰] = [(Rsample / Rstandard) -1] x 1000

where R denotes the isotope mass ratios of an element.

2 1 The H/ H ratios of water were measured on H2 gas generated by the chromium reduction technique (Gehre et al. 1996) from 4 ml of injected water and by using a dual inlet isotope ratio mass spectrometer (IRMS). The 18O/16O ratios of water were measured on

CO2 gas generated using the CO2-H2O equilibration technique (Epstein and Mayeda, 1953) on 1 ml of water. Note that the final set of samples taken in July 2008 was analyzed using pyrolosis TC/EA continuous flow isotope ratio mass spectrometry (CF IRMS). The δ18O and δ2H values are reported against the reference material V-SMOW and the measurement uncertainties for δ2H and δ18O values were ±2‰ and ±0.2‰ respectively.

Approximately 100-300µg of dried BaSO4 precipitate was weighed and packed into tin 34 32 cups for S/ S ratio measurements using SO2 gas generated via combustion in an elemental analyzer. The δ34S values were reported with respect to the reference V-CDT and the measurement uncertainty was ±0.3‰. Samples for the oxygen isotope ratio of sulphate were measured on CO gas generated by pyrolysis on 100-300µg of BaSO4 packed in silver cups. The final δ18O values were reported with respect to V-SMOW and the measurement uncertainty was ±0.5‰.

15 18 For δ NNO3 and δ ONO3 analysis, the bacterial denitrification method of Sigman et al.

(2001) and Casciotti et al. (2002) was used for the conversion of N2O gas from NO3 in water. The technique allows direct and simultaneous measurements of the 15N/14N and

18 16 O/ O ratios with CF-IRMS. The N2O gas is first trapped cryogenically in a Trace Gas Pre-Concentrator, subsequently separated in a gas chromatograph and finally passed into a mass spectrometer (Finnigan MAT delta plus XL) for isotope ratio measurements. 15 (NH4)2SO4 precipitates were prepared for δ NNH4 analysis using the diffusion trapping

technique described by Sebilo et al. (2004). Freeze-dried (NH4)2SO4 precipitates were packed into tin cups and thermally decomposed in an elemental analyzer (Fissions NA 15 1500) to generate N2 analyte gas. The final δ N values of NO3 and NH4 were reported 18 against atmospheric N2 whereas the δ ONO3 values were reported with respect to the international reference material V-SMOW. The precision and accuracy were ±0.2‰ for 15 18 δ N values of NO3 and NH4 and ±0.5‰ for δ O values of NO3.

3.3 Calculations Data Selection Most of the chemical and isotopic data were used. The ones excluded from interpretation included ion concentrations from two samples showing electrical charge balances

exceeding ±5% (Figure 3.3), and NO3 concentrations from four tributary samples (P5, P6, Q5 and R6 in Appendix B-II) with suspected measurement and/or reporting errors. The

reason for discarding the NO3 concentration data in these samples was based on the fact

that no N2O signal was detected by IRMS. The isotopic compositions of carbon in DIC 13 were also excluded from interpretation since half of δ CHCO3 values were deemed unreliable.

Daily flow measurements taken by Alberta Environment were obtained from the Water Survey of Canada (Water Survey of Canada 2009). Since flow was not measured at Canmore (99 km), it was estimated by adding the flow at Banff with the flow from the Spray River in Banff. The Bow River flow at the Bowness Park (212 km) in Calgary was assumed identical to that measured downstream at the AENV station above the Elbow River near 4th Street. Similarly, the flow at Bow City (482 km) 60 km downstream from the Bassano Dam was assumed to be the same as those measured just below the dam.

When there is no major tributary between the flow stations and the sampling sites, the assumption about constant flows is reasonable.

Sampling of the Bow River at Lake Louise (0 km), Cochrane (179 km), Carseland (302 km) and Ronalane (571 km) were at the same locations as AENV’s flow stations. Daily flow measurements for the Elbow River downstream of the Glenmore Dam, Highwood River near its mouth, Crowfoot Creek, New West Coulee, 12 Mile Creek and the major irrigation diversion canals (WID, BRID and EID) were also used. Since there is no AENV flow station at Cluny (378 km) and Scandia (513 km), solute load estimations for these two sites were not carried out. Missing flow data were extrapolated using historical averages.

Concentration-Flow Relationships To calculate annual mass loads of major ions, daily fluxes need to be calculated. For locations upstream of the Bassano Dam, daily fluxes for each ion were estimated by combining daily flows with the extrapolated daily concentrations according to the concentration-flow relationships in Table 3.2. Curve fitting was best matched by equations of the general form: y = ae-x/b+c (where y = concentration, x = flow and a, b and c are some constants), which resembles hyperbolic relationships typically observed in water quality studies (Hem 1985). For those solutes without a concentration-flow relationship, flow-weighted average concentrations of the monthly samples were used. As for the final reach of the river downstream of the Bassano Dam at Bow City (482 km) and Ronalane (571 km), concentration-flow relationships for Ca, HCO3 and SO4 were more complicated than those upstream of the dam. Therefore, more than one concentration-flow curves were used depending on season and whether flow was increasing or decreasing (Table 3.3).

Table 3.2 Summary of concentration-flow relationships (y as concentrations in mg/l and x as flows in m3/s) used in calculating the Bow River’s annual solute loads upstream of the Bassano Dam. For those solutes without a concentration-flow relationship, flow-weighted average concentrations were used.

Lake Louise Canmore Cochrane Calgary Carseland (0 km) (99 km) (179 km) (212 km) (302 km)

-0.09 (-x/51.81) (-x/25.46) (-x/30.07) HCO3 88.17 y = 179.1x y = 134.9+57.34e y = 134.3+234.1e y = 155.2+92.1e

-0.25 (-x/54.62) (-x/35.06) (-x/57.1) SO4 12.94 y = 92.88x y = 27.2+42.58e y = 27.5+94.73e y = 35.69+48.47e

Cl 0.224 y = 4.88x -0.41 1.429 y = 1.12+6.17e(-x/40.8) y = 3.96+24.53e(-x/38.56)

(-x/23.41) NO3 0.262 0.352 0.448 0.467 y = 1.14+54.37e

Ca 21.11 y = 65.73x-0.14 y = 37.7+25.71e(-x/52.51) y = 37.9+80.9e(-x/28.24) y = 42.2+40.06e(-x/38.01)

Mg 8.59 y = 18.03x-0.1 y = 11.9+6.6e(-x/54.75) y = 12.1+19e(-x/31.2) y = 13.61+7.24e(-x/56.93)

Na 0.575 0.58 2.355 y = 2.04+3.94e(-x/48.41) y = 7.92+20e(-x/25.81)

K 0.260 0.26 0.576 0.69 y = 1.17+2.85e(-x/44.8)

Table 3.3 Summary of the concentration-flow relationships used in calculating the annual mass loads of the Bow River below the Bassano Dam at Bow City and Ronalane. Bow City (482 km) Ronalane (571 km) -x/15.46 -x/24.25 HCO3 y = 137.72+1238.5e y = 127.27+647e (winter) y = 138.57+(7.66x10-6)ex/33.78 y = 156+197.42e-x/12.6 (rising limb) (rising limb) y = 128.35 + 0.00049ex/38.91 (falling limb) y = 128+89.14e-x/33.89 (fall) -x/22.45 -x/58.88 SO4 y = 41.45+229.05e y = 45.55+40.96e y = 39.61+428.66e-x/26.42 (rising limb) Cl y =4.77+180.08e-x/13.47 y = 4.36+19.96e-x/37.52 y = 4.51+100.02e-x/22.17 (rising limb)

-x/23.14 -x/23.14 NO3 y = 1.65+43.2e y = 1.55+43.2e Ca y =38.21+33.08e-x/16.92 y = 34.37+303.72e-x/21.28 (winter) y = 38.42+0.01e-x/86.51 y = 42.85+13.08e-x/73.43 (rising limb) (rising limb) y = 34.8+0.01ex/61.3 (falling limb) y = 34.95+31.26e-x/27.98 (fall) Mg y = 13.46+48.81e-x/22.21 y = 14+13.03e-x/44.38 Na y = 10.15+55.81e-x/21.86 y = 9.86+12.65e-x/76.13 y = 10.9+484.73e-x/16.38 (rising limb) K y = 1.36+20.86e-x/14.99 y = 1.27+2.16e-x/59.34

Annual Mass Loads The daily concentrations extrapolated from concentration-flow relationships in Table 3.2 3.3 allowed total annual mass loads of the major ions to be computed as summation of daily fluxes according to the following equation:

365

M i = ∑ (Q d × C i d ) d =1

The discharge-weighted annual average solute load (M i) of 2007 and 2008 was computed according the following equation:

(M i× Q T ) 2007 + (M i× Q T )2008 Average M i = QT 2007 + QT 2008

where the subscript i represents HCO3, SO4, Cl, NO3, Ca, Mg, Na and K, and the symbol T stands for total.

Since AENV’s flow monitoring sites are limited to three tributaries (Crowfoot Creek, 12 Mile Creek and New West Coulee), the highest annual discharge of 42 GL/yr (Crowfoot

Creek’s total discharge in 2008) was used to estimates the upper limit of NO3 mass loads for each of the nine intermittent prairie tributaries sampled (see Tables 7.2, Chapter 7).

The NO3 load estimation in Table 7.2 was interpreted to one significant digit.

Flux-Weighted Isotopic Averages: Flux-weighted average isotopic compositions in Chapter 6 and 7 were calculated according to the equation:

n (M i ×δ i ) δ average = ∑ 1 M i where n represents the total number of data, and i =1…n. In most cases, the monthly values (n=10) obtained during the sampling period (June 2007 to July 2008) were used. For samples showing correlations between isotopic values and flows or between the isotopic values and SO4 concentrations (Table 3.4), n were extended to include extrapolated daily values (n=365) throughout 2007 and 2008.

Isotope Mass Balance:

n ⎛ n ⎞ δ final = ∑ ( fi ×δi ); provided that ⎜∑ fi = 1⎟ 1 ⎝ 1 ⎠

where f is the fraction of contribution from source i having an isotopic value of δi and n is the total number of sources making up the final mixture. The final isotopic composition of the mixture is δfinal.

Table 3.4 Correlation equations used in calculating the average isotopic compositions of SO4 in Chapter 6. 34 18 δ SSO4 δ OSO4 Canmore (99 km) constant within 12-14‰ y = -1.32+5.0e-x/43.98 x = flow Cochrane –Calgary y = 11.88-673424.8e-x/2.18 y = -0.92+17.94e-x/27.69

(179-212 km) x = SO4 concentrations x = flow Carseland (302 km) y = 8.0-89705.8e-x/3.81 y = -1.48+27.32e-x/24.38

x = SO4 concentrations x = flow Highwood River y = -6.75+20.69e-x/10.26 y = -1.17+2.36e-x/30.54 (272 km) x = flow x = flow

CHAPTER 4: ISOTOPIC COMPOSITIONS OF WATERS

4.1 Introduction Water enters the hydrological cycle of a river basin via precipitation and ultimately leaves the cycle via streamflow and evapotranspiration (Freeze and Cherry 1979). Gravity flow controls the hydrology of a river basin. Snowmelt and rain infiltrating the unsaturated (vadose) zone between the ground surface and the groundwater table contribute to interflows (Freeze and Cherry 1979; Domenico and Schwartz 1990). Interflow contributions to streamflow reach its maximum during the snowmelt and rainfall period, and typically end by August as baseflow starts to dominate river flows (Domenico and Schwartz 1990). Overland flows generate rapid movement of water from land to streams and rivers, especially on steep slopes with thin regolith. A combination of pre-precipitation and precipitation waters runoff from the soil zone to rivers and contribute to peakflows in spring (Domenico and Schwartz 1990).

Flows in the Bow River originate from a combination of groundwater, snowmelt and rain whereas during baseflow period from August to April, the river is fed primarily by groundwater (Bow River Basin Council 2005). Melting of the winter snow packs is a dominant hydrologic event that occurs between May and early June every year. Depending on the moisture content in the vadose zone at the time of freezing, the freeze- thaw cycle of soil water in spring can cause the amounts and extents of infiltration versus overland flow to vary throughout a river basin (Wohl 2000). On a mountainous slope in British Columbia, the spring overland flow was determined to concentrate in a 30-40 cm band below the snow line (Slaymaker 1974). This zone of mobile melt water retreated uphill with the snow line as summer approached (Slaymaker 1974). Slaymaker (1974) demonstrated how snowmelt contribution area in a watershed changed in response to melting conditions. Clearly, the streamflow contribution area of a drainage basin is dynamic and can expand during precipitation and contract after precipitation. It was reported that the contributing area could range between 5 and 80% in a river basin (Dunne and Black 1970b; Selby 1982).

Moisture sources in southern Alberta predominantly originate from four airmass trajectories in the North Pacific Ocean between latitudes 40 and 60o N off the western coast of North America (Peng 2004; Government of Alberta 2009). In spring and summer, the southwest trajectory off the coast of California (40-45o N) provides the greatest (56%) amount of precipitation in southern Alberta (Peng 2004). Another estimate suggested this moisture source amounts to 45% of precipitation in southern Alberta and 25% at Calgary (Reinelt 1970). In addition, weather systems from the Gulf of Mexico can occasionally generate severe summer thunderstorms in Alberta with heavy downpours, hail and strong winds after a brief period of warm and humid weather conditions (Peng 2004; Government of Alberta 2009). In fall and early winter, westerly winds off the coast of British Columbia occasionally arrive in southern Alberta as warm and dry winds (Government of Alberta 2009) (see also Section 2.2, Chapter 2).

Precipitation is the source of groundwater and surface waters. Due to the unique geographical location of the Bow River Basin, the stable isotope ratios of H and O in precipitation are affected not only by the different moisture sources but also by continental and altitude effects. By the time an inland moving air mass reaches Alberta from the Northern Pacific Ocean, it had been depleted of moisture rich in heavy isotopes through precipitation (rainout effect). The isotopic composition of the remaining moisture consequently evolves towards increasingly more negative δ2H and δ18O values. By tracing the spatial changes of the δ2H and δ18O values in surface waters across the Great Divide from Vancouver to Calgary, Yonge et al. (1989) showed that to the west of the Great Divide, the δ2H and δ18O values decreased with inland distance and altitude in a pattern resembling that of a single Rayleigh distillation curve. To the east of the Great Divide, the δ2H and δ18O values increased linearly with inland distance, and the causes of this isotopic shift were attributed to evapotranspiration, mixing of different weather systems (Yonge et al. 1989; Ferguson 2007) and the distribution of winter and summer precipitation (Katvala 2008).

The Bow River hydrographs were compared to the monthly precipitation and daily irrigation withdrawal records. δ2H and δ18O values of the Bow River were traced with flow distance and season, and those of tributary waters and wastewater effluents from Calgary were assessed. The purpose was to verify sources of river flows and determine if effects of urban and agricultural activities can be discerned using the isotopic composition of H2O.

4.2 Precipitation across the Bow River Basin The General Distribution Pattern Precipitation distributes unevenly across the vast landmass (25,123 km2) of the Bow River Basin and southern Alberta (Figure 4.1). Between the Rocky Mountains to the west and the prairies to the east, Calgary generally receives around 400 mm of precipitation per year (Figure 4.1). East of Calgary on the Eastern Alberta Plain, Brooks receives less than 350 mm of precipitation annually (Figure 4.1). In contrast to the semi arid prairie climate, the Rocky Mountains and the Foothills to the west of Calgary typically receive between 500 and 600 mm of precipitation annually (Figure 4.1). The southwest corner of the Bow River Basin and the majority of the headwater catchments of the Oldman River Basin receive higher amounts between 600 and 800mm a year (Figure 4.1). The decrease in precipitation from northwest to southeast along the eastern slopes of the Rocky Mountains is related to the major moisture sources from the southwesterly winds off the coast of California (Peng 2004; Government of Alberta 2009). This weather system rises against the eastern slopes of the Rocky Mountains and travels north into Alberta before being deflected westward. The climatic condition of the Bow River Basin is not homogeneous but rather varies spatially between east and west.

Monthly precipitation records across southern Alberta during the study period between 2007 and 2008 are shown in Table 4.1 and Figure 4.2. From the Rocky Mountains to the Eastern Alberta Plain, data were obtained from Lake Louise, Banff, Calgary, Lethbridge and Brooks. These stations were chosen to assess the geographical distribution of precipitation affecting the Bow River Basin during the study period. Although

Lethbridge is neither within nor in the immediate vicinity of the Bow River Basin, it is reasonable to include it into the regional context because it is located in the same climatic zone shared by regions of the Bow River Basin on the prairies.

Precipitation Pattern during the Study Period The distribution of precipitation across the Bow River Basin in 2007 and 2008 was different. In 2007, precipitation decreased eastward as normal from the Rocky

Mountains to the prairies but the reverse occurred in 2008. At Lake Louise, Banff, Calgary, Lethbridge and Brooks, the amounts of precipitation received in 2007 were 534, 508, 319, 287 and 284 mm respectively (Table 4.1). In 2008, the precipitation pattern at Banff, Calgary, Lethbridge and Brooks were 396, 503, 475 and 289 mm. At Calgary, the total precipitation (319 mm) was lower than the usual average of 400 mm but in 2008, it (503 mm) exceeded the average and that at Banff (396 mm) (Table 4.1), which normally receives a much greater (500-600 mm) amount of precipitation (Figure 4.1). Another weather station, Lethbridge, located on the eastern border of the Western Alberta Plain also received unusually high amounts of precipitation in 2008. The interior of the Eastern Alberta Plain at Brooks however, received similar amounts (284–289 mm) of precipitation between the two years. The reversal of 2008 was between the Rocky Mountain and the Western Alberta Plain. Apparently, the prairies received less precipitation in 2007 than in 2008 while the Rocky Mountains received more precipitation in 2007 than in 2008.

Precipitation in southern Alberta from May to July, the snowmelt and rainfall period, also differed between the two years. In 2008, 295 mm of rain was received at Lethbridge in that period but in 2007, there was only 113 mm (Table 4.1; Figure 4.2). Similarly at Brooks, 177 mm was received between May and July of 2008, but only 114 mm was received in 2007 (Table 4.1). In contrast, the differences between the two years were small ~10 mm at Banff and Calgary (Table 4.1; Figure 4.2). Precipitation on the prairies was abundant throughout May to July in 2008 before it gradually decreased thereafter (Figure 4.2b). This was drastically different from the precipitation profile of 2007, which showed a lack of precipitation at Lethbridge in June and July (Figure 4.2a). July 2007 was the driest summer month during the entire study period. The fact that Calgary received persistent daily afternoon showers throughout the summer of 2008, but not 2007, was consistent with the long-term precipitation record.

Lake Louise Banff Calgary Lethbridge Brooks 2007 (mm) (mm) (mm) (mm) (mm) January 39.2 19.0 7.6 6.0 0 February 28.4 21.2 25.0 17.5 0 March 66.7 56.8 19.6 10.0 7.5 April 38.9 41.7 46.4 55.5 77.4 May 58.9 81.6 90.8 87.0 64.2 June 72.4 69.4 165.8 26.5 46.0 July 17.0 14.2 25.2 2.0 4.0 August 65.6 60.4 54.4 18.5 43.6 September 51.0 61.0 44.2 43 32.0 October 30.7 22.0 13.6 9.6* 3.2 November 25.2 21.7 9.4 2.6* (3) December (40) 39.3 6.4 9.0 3.5 Total 534 508 319 287 284

2008 January - 20.0 8.8 10.0 4.3 February - 13.1 11.8 5.5 3.8 March - 8.9 8.8 6.0 6.8 April - 32.3 35.8 20.5 11.7 May - 78.2 102.2 88.5 62.3 June - 44.9 113.3 92.0 63.2 July - 31.9 77.1 114.5 51.8 August - 50.1 53.6 30.0 17.6 September - 36.4 27.8 57.0 31.3 October - 25.2 8.4 12.5 18.2 November - 16.1 19.2 16.5 3.1 December - 39.1 35.8 21.5 14.6 Total - 396 503 475 289

Remarks: * data taken from a nearby weather station because measurements at the original station were not available - data not available because they were either no longer collected, missing, invalid or subjected to review by Environment Canada ( ) data not available but can be estimated based on other data collected within the same climatic zone

33 a b

180 180 Banff Calgary 160 160 Lethbridge

140 140

120 120

100 100

80 80

60 60

40 40 Monthly Total Precipitation (mm) (mm) Precipitation Total Monthly Monthly Total Precipitation (mm) (mm) Precipitation Total Monthly 20 20

0 0 Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec 2007 2008

4.3 Hydrographs of the Bow River The hydrographs of the Bow River at five locations are shown in Figure 4.3. The spring and summer flows of 2007 at Lake Louise and Canmore exceeded those in 2008 by a factor of 1-2 (Figure 4.3a). The higher headwater flows of 2007 were partly due to the fact that the Rocky Mountains received more precipitation in 2007 than in 2008. Peakflows at Cochrane however, were similar between the two years (Figure 4.3a), showing the effect of reduced flow in spring and summer as a result of increased upstream reservoir storage. Of the six dams in the Bow River Basin, three are located between Canmore and Cochrane. Multiple peakflow spikes were observed at Lake Louise and Canmore in 2008 (Figure 4.3a). Natural flows in the Rocky Mountains (0 – 99 km) during the snowmelt and rainfall season in 2008 fluctuated more frequently than in 2007 (Figure 4.3a). Fluctuating weather conditions can cause sporadic snowmelt events in the high elevation catchments, which in turn influence stream and river flows in the mountains.

As much of the spring snowmelt is held back by reservoirs (Bow River Basin Council 2005) upstream of Cochrane, flows reaching Calgary and the lower reaches are reduced. Throughout the prairie reaches in 2007, peakflows remained relatively constant

downstream of Cochrane at levels < 500 m3/s but in the following year, peakflows increased downstream of Cochrane and even approached 1000 m3/s (Figure 4.3a). Abundant rainfalls and runoff from late spring to early summer had contributed to the high flow levels in 2008.

1000 Sampling Period

100 /s) 3 Flow (m 10

1 12/1/2006 4/1/2007 8/1/2007 12/1/2007 4/1/2008 8/1/2008 12/1/2008 Date

b 1000

100 /s) 3 Flow (m

Lake Louise Canmore Cochrane Carseland Ronalane + Sampling Dates 1 5/1/2007 8/1/2007 11/1/2007 2/1/2008 5/1/2008 8/1/2008 Date

Figure 4.3 Daily flow of the Bow River at Lake Louise, Canmore, Cochrane, Carseland and Ronalane throughout a) 2007 and 2008, and b) during the field sampling period from June 2007 to July 2008. The shaded area shows when flows at Ronalane were significantly lower than those at Cochrane and Carseland (data source: Archived Hydrometric Data, Water Survey of Canada 2009).

The average total annual discharge of the Bow River at Ronalane, without the effect of diversion at WID, BRID and EID (-877 GL/yr), would be 4181 GL/yr (i.e. 4,181x106 m3/yr) (Table 4.2). The total input of flow from the Rocky Mountain catchments including contributions from the Elbow and the Highwood River watersheds were estimated to be 95.7% of the total discharge at Ronalane whereas drainage contributions from the prairies (0.3%) were relatively insignificant compared to the discharge of the Bow River (Table 4.2). Given that the 4.1% of discharge from the WWTPs in Calgary is mostly recycled riverine water from the Bow River and the Elbow River, Table 4.2 confirms that the Bow River discharge originates predominantly from the Rocky Mountains whereas flow contributions from the prairies is very small.

Estimated Estimated Gain/Loss Estimated Estimated Estimated Total Sources between Headwater WWTPs Prairie Stations Dist. Discharge /Sinks Stations Input Input Input (km) (GL) (GL) (GL) (%) (%) (%) LL 0 317 100 0 0 CM 99 1309 992 100 0 0 CC 179 3064 1755 100 0 0 BN 212 3026 -38 100 0 0 Elbow R. ~229 315 WID ~229 -93 WWTP 230 167 HW R. 272 695 BRID ~301 -295 CL 302 3687 -128 99.0 4.2 -3.2 EID 425 -489 BC 482 3158 -40 RL 571 3304 146 95.7 4.1 0.3

During the irrigation period, water withdrawals from the Bow River had significantly reduced flows in the Bow River. The observed effect at Carseland and Ronalane were most noticeable from July to September 2007 (Figure 4.3) as flow diverted daily to irrigate BRID and EID was high exceeding 30 m3/s (Figure 4.4). In 2007, the amounts of

water withdrawn to WID, BRID, and EDI were 85, 308 and 503 GL respectively (Figure 4.4). In 2008, water used by WID, BRID and EID were 99, 281 and 473 GL respectively (Figure 4.4). The plentiful spring and summer precipitation on the prairies in 2008 were helpful to supplement irrigation needs and a reduction of water withdrawals that year was evidence of this (Figure 4.4).

100

10 /s) 3 Flow (m 1

Withdrawal (GL) 2007 2008 WID 85 99 BRID 308 281 EID 503 473 0.1 1/1/2007 5/1/2007 9/1/2007 1/1/2008 5/1/2008 9/1/2008 1/1/2009 Date

Figure 4.4 Daily flows in the headwork irrigation canals of WID, BIRD and EID in 2007 and 2008.

4.4 Isotopic Compositions of Waters The Bow River The isotopic compositions of water from the Bow River and its tributaries on the prairies were different from those of the meteoric sources. The isotopic values of the Bow River water were noticeably higher than those of the winter precipitation but mostly lower than those of the summer precipitation (Figure 4.5). The Bow River values ranged from -20.5 to -16.7‰ for δ18O and from -160 to -138‰ for δ2H (Figure 4.5). Although some prairie tributary values overlapped with those of the Bow River between -18.8 and -16.7‰ for δ18O, and -149 and -138‰ for δ2H, most of the prairie tributaries had higher δ2H and δ18O values than the Bow River (Figure 4.5). The isotopic values for these tributaries

varied between -18.8 and -9.5‰ for δ18O, and between -149 and -94‰ for δ2H (Figure 4.5). These isotopic values plotted on or above the local evaporation line (LEL) (Ferguson et al. 2007) and below the local meteoric water line (LMWL) (Peng 2004) (Figure 4.5). Many data points from the prairie tributaries had isotopic values between the shallow groundwater line (SGWL) (Cheung 2009) and LEL as oppose to those from the Bow River plotting close to the LMWL (Figure 4.5).

-80 Bow River L L W W L M G E Tributary L S L -100 Precipitation at Calgary

-120 summer

-140 (‰)

H2O -160 H 2 δ

-180 winter

2 18 LMWL: δ H = 7.68δ O - 0.21 -200 2 18 SGWL: δ H = 6.3δ O - 30.1 2 18 LEL: δ H = 4.3δ O - 62 -220 -30 -25 -20 -15 -10 -5 18 δ O (‰) H2O

Figure 4.5 δ2H and δ18O values of waters from the Bow River and its tributaries shown together with the LEL (Ferguson et al. 2007), SGWL (Cheung 2009) and LMWL (Peng 2004).

Tributaries on the Prairies Although the Highwood River joins the Bow River on the prairies, its δ2H and δ18O values resembled those of the Bow River as can be expected since both rivers originate in the Rocky Mountains. Unlike the Highwood River, prairie tributary waters do not originate from the Rocky Mountains, and many were enriched in 18O and 2H. The extent of the enrichment of heavy isotopes appeared to increase in waters sampled towards the

final reach of the river. The isotopic composition of H2O in most tributaries (open circles) of the EID and some Crowfoot Creek waters were similar to that of the Bow

River whereas those from BRID exhibited substantial enrichments of 2H and 18O in contrast to δ2H and δ18O values of the Bow River (Figure 4.6).

-90

-100 2 18 2 δ H = -45.5 + 5.36δ O (n=49; r =0.9672)

-110

-120 (‰)

H2O -130 H 2 Highwood River δ Crowfoot Ck. -140 E1413 (12 Mile Ck.) EID: (1717, 1716, 1616, 1415) BRID: -150 B1516 B1416 (New West Coul.) Bow River Range B1212 -160 -20 -18 -16 -14 -12 -10 -8 18 δ O (‰) H2O

Figure 4.6 δ2H and δ18O values of waters from tributaries discharging into the Bow River on the prairies.

E1413 (12 Mile Creek) and B1212, the final outlets of irrigation canals within EID and BRID respectively, had the highest δ2H and δ18O values towards the upper range of the regression line in Figure 4.6, plotting between the SGWL and LEL lines in Figure 4.5. E1413 and B1212 may contain substantial amounts of unused irrigation waters that had been subjected to evaporation in open canals and reservoirs before being diverted back to the Bow River. The longer the residence time of flow in irrigation canals, the higher the isotopic values of the waters may become due to evaporation. Prairie tributary waters towards the east near the Bow River confluence with the Oldman River were clearly affected by evaporation. In the order from the highest δ2H and δ18O values to the lowest, they include B1212, E1413, B1416, and B1516. B1212, E1413, and B1416 are major return flow sites monitored by AAFRD (see Figure 3.2, Chapter 3) and their confluence with the Bow River are located downstream of Scandia (513 km).

Wastewater Effluent The isotopic composition of wastewater effluents from Calgary were slightly higher than that of the Bow River upstream of the Wastewater Treatment Plants (WWTPs) exhibiting small differences of <0.5‰ for δ18O and <4‰ for δ2H (Figure 4.7). Within the wastewater plume in the Bow River (12-14 km downstream of WWTPs’ outlets) (Vandenberg 2005), isotopic differences with respect to the Bow River were even smaller (Figure 4.7). The slightly higher δ2H and δ18O values in treated effluents were likely caused by evaporation during the early stage of filtration in large open sedimentation

tanks. Figure 4.7 shows that the isotopic composition of H2O from wastewaters did not have a significant influence on the isotopic composition of the Bow River water.

-136

-140

-144

(‰) (‰) -148 H2O H 2 δ -152

-156 Wastewater Effluent Bow River abv WWTPs Wastewater Plume -160 -21 -20 -19 -18 -17

18 δ O (‰) H2O

Figure 4.7 δ2H and δ18O values of waters from Calgary’s WWTPs (red), instream wastewater plume at 482 km (green), and upstream of the WWTPs (blue).

Temporal and Spatial Variations The δ18O and δ2H values increased along the flow distance of the Bow River (Figure 4.8) with the largest difference occurring between Lake Louise (0 km) and Calgary (212 km). Throughout the prairies from Calgary to Scandia (513 km), the δ18O and δ2H values only

increased slightly (Figure 4.8). The maximum extent of increases in the δ18O and δ2H values from headwater to mouth were less than 2‰ for δ18O, and about 10‰ for δ2H (Figure 4.8). The isotopic composition of precipitation in the Rocky Mountains at different elevations had an eastward increasing δ18O and δ2H trend just like that of surface waters from the Rocky Mountains to Calgary (Hogue 2009; Katvala 2008). The causes of increasing isotopic values with flow distance were attributed to a combination of evaporation occurring in rivers, reservoirs, lakes and wetlands and a shift from snowmelt to rainfall dominated stream flow generation (Katvala 2008).

Jul07 Nov07 May08 Aug-Oct07 Apr08 Jun08

-16.2

-16.8

-17.4

-18.0 -18.4 (‰) -18.6 H2O

18 -19.2 δ -19.8

-20.4 CM CC CL CN BC SD RL LL -21.0

-136

-140 -142

-144 (‰) (‰)

H2O -148 H 2 δ -152

-156

-160 0 100 200 300 400 500 600

Distance (km)

During the late fall and spring baseflow period (Nov07 and Apr08) and the peakflow

period in June, the isotopic composition of H2O in the Bow River at Ronalane (571 km) were similar to those of the upstream reaches (Figure 4.8). Elevated δ18O and δ2H values higher than those upstream of Scandia (513 km) were observed at Ronalane (571 km) during the irrigation season in May 2008 and from July to October 2007 (Figures 4.8 4.9). The abrupt increases of δ18O to >-18.4 ‰ and of δ2H to >-142 ‰ occurred within 60 km downstream of Scandia (513 km), coinciding with discharges of tributary waters that had been subjected to evaporation (e.g. B1416 and E1413) (see Figure 4.6).

The monthly δ18O and δ2H values of the Bow River showed seasonal variations (Figure 4.9). Maximum δ18O and δ2H values in the Bow River between Calgary and Scandia (248-513 km) occurred in June, August, September and October whereas the minimum values occurred in July, late November and April (Figure 4.9). Similarly, the δ18O values in the Bow River at Lake Louise (0 km) decreased from June to July by 0.4% and then varied little throughout the rest of the year (Figure 4.9). The highest δ2H values occurred in August between Lake Louise and Calgary (0-179 km) as opposed to in September between Bow City and Scandia (482-513 km) (Figure 4.9). In spring and summer, the δ2H values of the Bow River decreased from April or May towards a minimum at the end of July (Figure 4.9).

The δ18O and δ2H values of the Bow River at Ronalane (571 km) were much higher from July to October in comparison to the rest of the river upstream of Ronalane (571 km) (Figure 4.9). The irrigation season was over by early October and yet the isotopic compositions of the Bow River water at Ronalane (571 km) still remained high in late October. This suggests that the Bow River at Ronalane (571 km) in mid fall was under the influence of agricultural return flows or regional groundwater with elevated δ18O and δ2H values. Agricultural return flow may consist of two components. It could be residual waters in open irrigation canals or leached irrigation waters from agricultural fields that had become a part of subsurface flows or groundwater. Since both components of the agricultural return flow are subjected to evaporation, the isotopic

compositions of these waters cannot be effectively used to distinguish between the pathways of the agricultural return flows or to separate it from the groundwater component. Nevertheless, Figures 4.8 and 4.9 demonstrate that δ18O and δ2H values can provide information about when and where the Bow River is most likely affected by agricultural return flows that had been subjected to substantial evaporation. Except for the peakflow period in June, it appeared that the Bow River downstream of Scandia (513 km) was affected by δ18O and δ2H values of evaporated tributary waters throughout the irrigation season from May to the end of October.

-16.2 0 km -16.8 99 km 179 km -17.4 248 km -18.0 482 km

(‰) 513 km -18.6 H2O

O 571 km 18

δ -19.2

-19.8

-20.4

-21.0

-136

-140

-144 (‰) H2O -148 H 2 δ

-152

-156

-160 6/1/2007 9/1/2007 12/1/2007 3/1/2008 6/1/2008 9/1/2008

Monthly δ2H-δ18O Relationships Although the river water at Ronalane (571 km) had higher δ18O and δ2H values relative to the rest of the river in the upstream reaches throughout the irrigation season (except during peakflow in June), the isotopic composition of water from Ronalane in July and August plotted on the same regression line as the rest of the river (Figure 4.10). This indicates that in the summer, the elevated δ18O and δ2H values at Ronalane were not caused by evaporation. In May, September and October, the data points (red) from Ronalane plotted below the regression lines of the river (Figure 4.10), suggesting that the Bow River water at Ronalane was affected by evaporation. The observed isotopic shifts in May, September and October at Ronalane cannot be explained entirely by instream evaporation since the effect of evaporation was high only during summer as shown by the slopes in Table 4.3. It appeared that the isotopic composition of H2O may potentially be useful for tracing irrigation waters returning to the Bow River via subsurface flow paths in fall and spring.

Based on the slopes of the regression lines in Table 4.3, October and May were the only two months when the isotopic compositions of the Bow River had slope values (7.8) similar to that of the LMWL (7.7) in Figure 4.5. Throughout the summer (June to September) of 2007, the slopes of δ2H-δ18O relationships were between 5.3 and 5.7 showing the effect of evaporation. The unusually high slopes of 9.2 and 9.7 in November of 2007 and June of 2008 (Table 4.3) were probably not representative of the Bow River as the river was partially frozen by late November in 2007, and was flooded on the sampling date in June 2008. The frozen and flooding conditions may create spatial discontinuity along the flow path of the river and therefore, the samples collected may not represent well-mixed water compositions.

-132 -132 -132 Jun07 Jul07 Aug07

-136 -136 -136

-140 -140 -140

-144 -144 -144

-148 -148 -148 H-water (‰) H-water (‰) H-water (‰) 2 2 2 δ δ δ -152 -152 -152

-156 -156 -156

-160 -160 -160 -21.0 -20.4 -19.8 -19.2 -18.6 -18.0 -17.4 -16.8 -16.2 -21.0 -20.4 -19.8 -19.2 -18.6 -18.0 -17.4 -16.8 -16.2 -21.0 -20.4 -19.8 -19.2 -18.6 -18.0 -17.4 -16.8 -16.2

18 18 18 δ O-water (‰ ) δ O-water (‰) δ O-water (‰)

-132 -132 -132 Sep07 Oct07 Nov07

-136 -136 -136

-140 -140 -140

-144 -144 -144

-148 -148 -148 H-water (‰) (‰) H-water H-water (‰) (‰) H-water (‰) H-water 2 2 2 δ δ δ -152 -152 -152

-156 -156 -156

-160 -160 -160 -21.0 -20.4 -19.8 -19.2 -18.6 -18.0 -17.4 -16.8 -16.2 -21.0 -20.4 -19.8 -19.2 -18.6 -18.0 -17.4 -16.8 -16.2 -21.0 -20.4 -19.8 -19.2 -18.6 -18.0 -17.4 -16.8 -16.2

18 18 18 δ O-water (‰ ) δ O-water (‰) δ O-water (‰)

-132 -132 -132 Apr08 May08 Jun08

-136 -136 -136

-140 -140 -140

-144 -144 -144

-148 -148 -148 H-water (‰) H-water (‰) H-water (‰) 2 2 2 δ δ δ -152 -152 -152

-156 -156 -156

-160 -160 -160 -21.0 -20.4 -19.8 -19.2 -18.6 -18.0 -17.4 -16.8 -16.2 -21.0 -20.4 -19.8 -19.2 -18.6 -18.0 -17.4 -16.8 -16.2 -21.0 -20.4 -19.8 -19.2 -18.6 -18.0 -17.4 -16.8 -16.2

18 18 18 δ O-water (‰ ) δ O-water (‰) δ O-water (‰)

Figure 4.10 Dual isotope diagram for the Bow River water from June to November in 2007 and from April to July in 2008. 44

Table 4.3 Summary of regression equations between δ18O and δ2H values for the Bow River in each month. Intercept Slope n r2 June 2007 -40.6 5.7 10 0.8585 July 2007 -40.7 5.7 10 0.9164 August 2007 -43.9 5.4 10 0.8901 September 2007 -41.0 5.5 9 0.9504 October 2007 1.9 7.8 9 0.9356 November 2007 25.1 9.2 9 0.8954 April 2008 -41.1 5.6 10 0.7175 May 2008 1.7 7.8 9 0.9335 June 2008 40.9 9.7 10 0.8931 July 2008 -31.7 6.1 10 0.9163

Variations with Flow On heavy rainfall days, irrigation withdrawals were reduced to below 2m3/s at the WID and BRID weirs and diversion to EID was also low around 10m3/s (Figure 4.4). The Bow River’s flow during this period is least affected by irrigation withdrawal, and the δ18O and δ2H values increased slightly with increasing flow and distance (Figure 4.11). This reflects the fact that sources of runoff water in June from the prairie reaches are relatively enriched in 2H and 18O in comparison to the snowmelt and rain derived runoff water from the Rocky Mountains. δ18O and δ2H values increased by 1.3‰ and 13 ‰ respectively between the Rocky Mountains and the prairies while flows from the headwater reach to the river mouth increased from ~20 m3/s to ~500 m3/s (Figure 4.11).

In contrast to peakflow, when river flows were low <50m3/s on the prairies (grey) and <25m3/s at Canmore (99 km), δ18O and δ2H values of river waters are high in contrast to lower isotopic values around -19.8‰ for δ18O and -152‰ for δ2H when flows exceeded 100m3/s (Figure 4.11). Decreased δ18O and δ2H values with increasing flows indicate that snowmelt in the Rocky Mountains is an important source of flows in the Bow River.

-16.2 0 km 99 km -16.8 179-212 km 302-513 km -17.4 571 km

-18.0

(‰) -18.6 377.6571.4 481.8 H2O

O 513.1

18 -19.2 301.6

δ 211.7 178.8 -19.8 99.1 0 Peakflow in June: y = -20+0.0022x (n=9; r2=0.9241) -20.4

-21.0 0 100 200 300 400 500 600 Flow (m3/s)

-132

-136

-140 571.4 301.6 481.8 377.6 -144 513.1 (‰) 211.7 H2O -148 178.8 H 2 δ

0 -152 99.1 Peakflow in June: y = -154+0.0223x (n=9; r2=0.8819) -156

-160 0 100 200 300 400 500 600 Flow (m3/s)

4.5 Summary The distribution of precipitation throughout the BRB was different between 2007 and 2008. In 2007, the Rocky Mountains received a higher amount of precipitation than the prairies whereas in 2008, the condition was reversed. The effect of varied precipitation distribution was reflected in river discharge. The headwater reaches in the Rocky Mountains had higher spring and summer flow in 2007 than in 2008, whereas the prairie reaches had higher spring and summer flow in 2008 than in 2007.

Except for the peak runoff period in June, δ2H and δ18O values of the Bow River water decreased with increasing flow. The inverse relationship between the isotopic

composition of H2O and flow shows the importance of snowmelt contribution to flows in the Bow River. The close proximity of the δ2H-δ18O regression lines to the LMWL in spring and fall in comparison to the lowered slopes of the δ2H-δ18O relationships from June to September indicate that the Bow River was affected by evaporation throughout the summer.

The Bow River downstream of Scandia was most affected by tributary waters enriched in 2H and 18O in September, October and May. The somewhat sudden increase in δ2H and δ18O values in the Bow River downstream of Scandia (513 km) was partially caused by prairie tributary discharges containing substantial amounts of evaporated agricultural return flows. The wastewater effluents from Calgary on the other hand, had no significant impact on the isotopic composition of the Bow River water. The δ18O and δ2H values can be useful for identifying agricultural return flows affected by evaporation in the final reach of the Bow River but they are not suitable for tracing wastewater effluents from Calgary’s WWTPs in the river.

CHAPTER 5: MAJOR ION CHEMISTRY OF THE BOW RIVER

5.1 Introduction Water-rock interactions through weathering have a direct influence on groundwater and surface water chemistry. Since the Bow River Basin covers an extensive drainage area and flows across a wide range of physiographic and geologic regions, it is likely that the variations in the natural chemistry of the Bow River water are partially a reflection of the lithological variations within the basin. The physiographic and geologic features of the Bow River Basin vary greatly across its 15,123 km2 watershed. Physiographic divisions from west to east include the Rocky Mountains, the Rocky Mountain Foothills, the Southern Alberta Uplands, the Western Alberta Plains and the Eastern Alberta Plains (Pettapiece 1986) accompanied by a decrease in elevation from 3400 masl at the continental divide to 740 masl at the mouth of the Bow River (Bow River Basin Council 2005). The Rocky Mountain consists of the Main Ranges and the Front Ranges divided near the Pipestone Thrust belt (Hamilton et al. 1999). The headwaters of the Bow River originate in the Rocky Mountains dominated by Paleozoic and Late Precambrian sedimentary rocks whereas in the Rocky Mountain Foothills, the river crosses formations of Tertiary, Cretaceous, Jurassic and Triassic ages (Pettapiece 1986; Section 2.4, Chapter 2).

The Rocky Mountains and the Foothills together constitute the eastern portion of the western Canadian Cordilleran, yet most of Alberta lies in the Interior Plains (Chapter 2 Figure 2.1). Because of the westward dipping nature of the sedimentary strata in the Interior Plains, bedrock geology of the Bow River Basin grades into older strata down gradient along the Bow River. The young Tertiary bedrock material consisting mainly of sandstone and shale underlies much of the Southern Alberta Uplands and the Western Alberta Plains, whereas older strata of Upper Cretaceous age are exposed throughout the Eastern Alberta Plains (Hamilton et al. 1999; see also Section 2.4, Chapter 2). The Paleozoic, Mesozoic and Tertiary bedrock strata throughout the Interior Plain are overlain by Pleistocene glacial deposits. Glacial drift and bedrock geology are the two most

49 important hydrogeological entities of the Interior Plains (Meyboom 1967). Glacial drift overall consists on average of 60% till, 40% lacustrine sediment and less than 1% outwash deposit (Meyboom 1967).

Major ions (Ca, Mg, Na, HCO3, SO4 and Cl) are the primary constituents of river chemistry and are the common major inorganic solutes of waters in sedimentary basins, and in groundwaters (Hem 1985; Hounslow 1995; Wohl 2000). These ionic solutes mainly come from mineral weathering occurring on various time scales in the subsurface and in the soil zone (Drever 1982; Hem 1985; Hounslow 1995). Major ions are the basic and fundamental constituents for classification of water types as the chemical evolution of groundwater and surface waters is closely related to changes in the major ion concentrations. In addition to geological sources for the major ions, anthropogenic inputs can potentially alter the natural composition of groundwater and river waters. For the Bow River Basin, wastewater effluents at Calgary and agricultural return flows in the irrigation districts east of Calgary are potentially the two most important anthropogenic sources.

Agricultural return flow refers to either used or unused irrigation water that is diverted from and then returned back to the river through constructed irrigation works (AAFRD 2007). Drainage waters can also return to the river via surface runoff during major rain events or via subsurface flow as groundwater discharge (Alberta Environment 2003). Prairie tributaries within the irrigation districts (WID, BRID and EID) are used to convey and drain unused water back to the Bow River (AAFRD 2007) and are referred to by AAFRD as return flow streams. Since agricultural return flow in various amounts may constitute a component of the prairie tributary waters, the prairie tributary waters should not be mistaken as agricultural return flow waters. Quantifying the amount of agricultural return flow to the Bow River is difficult because it is a diffuse source, but inferences may be made based on the major ion composition of these tributary waters.

Due to the distribution of population densities in the Bow River Basin, anthropogenic loadings to the Bow River are expected to be most significant at and downstream of Calgary. Chemical compositions of the river water at various sites upstream and downstream of Calgary in addition to the wastewater effluents and the selected prairie tributary waters were assessed in order to determine the impact of the wastewater and agricultural return flows on the water quality of the Bow River. In this chapter, major ion concentrations are interpreted with the following goals: a) identify correlations between lithological compositions and water chemistry; b) characterize the major ion chemistry of the return flow tributary waters; c) evaluate the extent of urban impact on the chemical composition of the Bow River; d) determine origins of major ions and quantify their relative contributions.

5.2 Discharge and Solute Loads in the Bow River In this chapter, the terms “solute load” and “discharge” refer to the annual total mass loads (in kt) and water volumes (in GL) transported by the Bow River throughout 2007 and 2008. These estimated values are essentially the annual mass load fluxes and volumetric discharges with units of kt/year and GL/yr respectively. In order to distinguish the difference between the short-term rates from the calculated or extrapolated yearly amounts, the terms flow and flux are used in the context when referring to short-term instantaneous or daily rates of transport in volume of water and mass load of solutes respectively. Given that the total annual solute loads and discharges are computed as summations of the daily fluxes and flows respectively, it is necessary to clarify these differences. The computed results are summarized in Table 5.1 and 5.2. The discharge weighted average values in Table 5.2 were used to plot Figures 5.1, 5.2 and Figure 5.4 whereas the absolute values for 2007 and 2008 in Table 5.1 were used in Figure 5.3. The original analytical results for the chemical compositions of the Bow River waters, tributary waters and the wastewaters are summarized in Appendix B – Part I, II and III respectively.

Year Total Avg. 2007 Distance Discharge Ca Mg Na K HCO3 SO4 Cl NO3 NH4 Load TDS [km] [GL] [kt] [kt] [kt] [kt] [kt] [kt] [kt] [kt] [kt] [kt] [mg/L]

Lake Louise 0 342 7.2 2.9 0.2 0.1 31.5 4.4 0.1 0.1 d.l. 47 136 Canmore 99 1406 51 17 0.8 0.4 180 46 1.3 0.49 d.l. 296 211 Cochrane 179 3063 128 40 7 1.8 440 105 4.4 1.4 d.l. 727 237 Calgary 212 3023 128 40 8 2.1 435 107 5.4 1.4 d.l. 727 241 Carseland 302 3400 155 50 29 5.1 544 147 21 9.0 d.l. 960 282 Bow City 482 2937 125 45 36 4.7 440 149 18 9.4 d.l. 827 282 Ronalane 571 3075 134 48 40 5.2 474 163 19 9.0 d.l. 893 290

Highwood River 272 +525 27 7.5 4.8 0.7 103 22 1.4 0.1 d.l. 167 318 WID 229 -85 3.4 1.1 0.21 0.06 12 2.7 0.13 0.04 d.l. 19 227 BRID 301 -308 14 4.5 2.6 0.44 49 13 1.7 0.67 d.l. 86 279 EID 422 -503 22 8.7 6.9 1.1 78 28 3.6 2.1 d.l. 149 297 TPBBTP1 231 +145 9.0 3.7 12 2.2 22 19 12 9.4 0.14 89 612 TPFCTP2 245 +27 2.1 0.9 2.5 0.29 9.0 4.8 2.7 0.01 0.58 23 864

Year Total Avg. 2008 Distance Discharge Ca Mg Na K HCO3 SO4 Cl NO3 NH4 Load TDS [km] [GL] [kt] [kt] [kt] [kt] [kt] [kt] [kt] [kt] [kt] [kt] [mg/L]

Lake Louise 0 288 7.2 2.9 0.2 0.1 32 4.4 0.1 0.1 d.l. 47 162 Canmore 99 1195 45 14 0.7 0.3 156 41 1.2 0.42 d.l. 259 217 Cochrane 179 3065 128 40 7.2 1.8 441 105 4.4 1.4 d.l. 728 238 Calgary 212 3029 128 40 7.9 2.1 436 107 5.4 1.4 d.l. 727 240 Carseland 302 3936 177 57 33 5.6 626 166 22 8.9 d.l. 1096 278 Bow City 482 3352 147 50 42 5.3 517 169 20 10.3 d.l. 961 287 Ronalane 571 3505 150 54 44 5.7 531 182 21 9.6 d.l. 998 285

Highwood River 272 +806 41 11 7.0 1.1 156 31 2.0 0.2 d.l. 250 310 WID 229 -99 4 1.3 0.24 0.07 14 3.1 0.13 0.05 d.l. 22 225 BRID 301 -281 13 4.1 2.4 0.40 45 12 1.6 0.62 d.l. 78 279 EID 422 -473 22 7.8 7.2 0.88 76 27 3.5 1.9 d.l. 146 308 TPBBTP1 231 +137 8.4 3.5 11 2 21 18 11 8.9 0.08 84 612 TPFCTP2 245 +26 2.1 0.9 2.4 0.28 8.7 4.7 2.6 0.01 0.57 22 864

d.l. - stands for the “detection limit” of concentration measurements _ - estimated using more than one concentration-flow curve as the relationship seems seasonally and hydrologically variable

Locations along the Total Avg. Bow River Distance Discharge Ca Mg Na K HCO3 SO4 Cl NO3 NH4 Load TDS [km] [GL] [kt] [kt] [kt] [kt] [kt] [kt] [kt] [Kt] [kt] [kt] [mg/L]

Lake Louise 0 317 7.2 ± 0.7 2.9 ± 0.3 0.20 ± 0.02 0.09 ± 0.01 32 ± 3.1 4.4 ± 0.4 0.08 ± 0.01 0.09 ± 0.01 d.l. 47 147 Canmore 99 1309 48.2 ± 3.9 16 ± 1.4 0.75 ± 0.07 0.34 ± 0.03 169 ± 15 44 ± 3.1 1.2 ± 0.1 0.46 ± 0.03 d.l. 279 213 Cochrane 179 3064 128 ± 8 40 ± 2.4 7.2 ± 0.6 1.8 ± 0.2 441 ± 31 105 ± 5.2 4.4 ± 0.3 1.37 ± 0.15 d.l. 728 238 Calgary 212 3026 128 ± 8 40 ± 2.4 7.9 ± 0.8 2.1 ± 0.2 435 ± 26 107 ± 4.3 5.4 ± 0.6 1.41 ± 0.16 d.l. 727 240 Carseland 302 3687 167 ± 15 54 ± 4.3 31 ± 2.2 5.4 ± 0.4 588 ± 53 157 ± 11 22 ± 1.3 8.9 ± 0.36 d.l. 1033 280 Bow City 482 3158 137 ± 15 48 ± 4.8 39 ± 4.7 5.0 ± 0.6 481 ± 53 160 ± 18 19 ± 1.5 9.9 ± 0.87 d.l. 899 285 Ronalane 571 3304 142 ± 16 51 ± 5.1 42 ± 3.8 5.4 ± 0.4 505 ± 56 173 ± 16 20 ± 1.6 9.3 ± 0.82 d.l. 949 287

Major Inputs and Withdrawals

Highwood River 272 +695 35 ± 4.8 9.7 ± 1.3 5.7 ± 0.3 0.9 ± 0.13 135 ± 19 28 ± 3.2 1.3 ± 0.2 0.27 ± 0.01 d.l. 217 312 WID Canal 229 -93 4 ± 0.2 1.2 ± 0.1 0.2 ± 0.02 0.06 ± 0.01 13 ± 0.8 3 ± 0.1 0.1 ± 0.01 0.04 ± 0.005 d.l. 21 226 BRID Canal 301 -295 13 ± 1.2 4.3 ± 0.3 2.5 ± 0.2 0.4 ± 0.03 47 ± 4.2 13 ± 0.9 1.7 ± 0.1 0.65 ± 0.03 d.l. 82 279 EID Canal 422 -489 22 ± 2.4 8.2 ± 0.8 7.0 ± 0.8 1.0 ± 0.11 77 ± 8.4 28 ± 3.0 3.5 ± 0.3 2.0 ± 0.2 d.l. 148 302

TPBBTP1 231 +141 8.7 ± 0.5 3.6 ± 0.6 11 ± 0.9 2.1 ± 0.14 22 ± 2.8 18 ± 2.4 11 ± 1.5 9.2 ± 1.1 0.23 ± 0.03 86 612

TPFCTP2 245 +26 2.1 ± 0.1 0.92 ± 0.15 2.4 ± 0.2 0.3 ± 0.03 8.9 ± 0.6 5 ± 0.8 2.7 ± 0.3 0.01 ± 0.004 1.14 ± 0.02 23 864

TP1+2 248 +167 11 ± 0.6 4.5 ± 0.7 14 ± 1.1 2 ± 0.2 30 ± 3.4 23 ± 3.3 14 ± 1.7 9.2 ± 1.1 1.37 ± 0.05 109 1476 d.l. - stands for the “detection limit” of concentration measurements _ - estimated using more than one concentration-flow curve as the relationship seems seasonally and hydrologically variable 52

5.2.1 Upstream of Calgary The Rocky Mountains The total solute load of the Bow River is a function of TDS and discharge because the flux of the ionic solute load is the product of concentration and flow. In the mountainous regions, TDS increase is highest from the Main Ranges at Lake Louise (0 km) with 136 mg/L to the Front Ranges at Canmore (99 km) with 213 mg/L, but the extent of this TDS increase (79 mg/L) is not fully mirrored by a proportional solute load increase (232 kt) between the two sites (Figure 5.1). Instead, the highest solute load increase of 449kt occurs in the Bow River between the Front Ranges at Canmore (99 km) with 279kt and the end of Foothills at Cochrane (179 km) with 728kt (Figure 5.1).

A large TDS rise accompanied by a small discharge increase throughout the Main Ranges and the Front Ranges (0-99 km) suggests that the solute fluxes from the high elevation sub-watersheds of the Bow River Basin are high. In contrast, the trends throughout the lower Front Ranges and the Foothills (99 - 179 km) exhibited a different pattern in which a large increase in discharge accompanied by a smaller TDS increase suggests that the solute fluxes from the lower river valleys of the Rocky Mountains are less than that of the higher elevation watersheds. This discrepancy between the different amounts of mass load inputs from within the Rocky Mountains shows an apparent relationship between elevation and riverine solute loads. This relationship supports the fact that riverine TDS levels are influenced by a combination of factors including rock type, relief, climate and vegetation (Drever 1982; Wohl 2000). The combined effects of these natural factors affect chemical weathering rate and mountain hydrology that in turn affect the delivery and export of solute loads to streams and rivers.

The abundant exposure of fresh carbonate rocks associated with the high elevation catchments of the Main Ranges provides favourable conditions for chemical weathering. The poor soil development and steep slopes on these high mountain ranges can also aid in the transport of solutes to streams and rivers. This is because the hydrology of these high order mountain tributaries can respond more rapidly to snowmelt and summer

54 precipitation events (Wohl 2000). This increases the chance of mass load inputs to a river via near surface drainage pathways close to the bedrock surface. Since this hypothesis is based on only three sampling points, further evaluation is required to ensure the robustness of this observation. This will require an assessment of the various factors controlling weathering rates and the subsequent mass load transport to the Bow River on a basin wide scale. The data showed that the Rocky Mountain watersheds of the Bow River Basin including inputs from the Elbow and the Highwood Rivers contributed the majority 84% (Figures 5.2-5.3) of the solute load to the Bow River at the mouth. The greatest increase in TDS, solute load and discharge all occurred within headwater reaches prior to the transition into the Southern Alberta Uplands at Cochrane (179 km).

Southern Alberta Uplands Throughout the Southern Alberta Uplands between Cochrane (179 km) and Calgary (212 km), the discharge of the Bow River decreased on average by 38GL (40 GL in 2007 and 36 GL in 2008) after passing the Bearspaw Dam located northwest of the City of Calgary (Table 5.1 and 5.2). The Bearspaw Dam in addition to providing approximately half of Calgary’s water supply is mainly used for hydroelectric power production and flood control (Bow River Basin Council 2005; Natural Resources Canada 2008). Although the overall effect of regulated flow by the dam on TDS, solute load and discharge of the Bow River immediately downstream of the dam appeared to be minimal (Figure 5.1), close inspection on the trends showed small but noticeably permanent alteration to all three parameters by the effect of damming the flow (see Section 5.3).

The near constant trends in Figure 5.1 between Cochrane (179 km) and Calgary (212 km) indicate that headwater mass load contributions to the Bow River diminish abruptly upon exiting the Rocky Mountain Foothills. Anthropogenic inputs to the Bow River between Cochrane (179 km) and Calgary (212 km) are likely small as wastewaters from Cochrane, the only major urban centre within this stretch of the river, is piped to Calgary for treatment at the Bonnybrook Wastewater Treatment Plant (Bow River Basin Council 2005). The absence of large tributaries in this reach of the Bow River explains the near

constant solute load levels observed. It also implies that mass load contribution from groundwater inflow to the Bow River is likely small in this reach. Given that TDS generally increases in concert with discharge prior to the Bassano Dam (Figure 5.1), the trends from the Rocky Mountains to Calgary (212 km) suggest that the Bow River discharge has a dominant control over the river’s solute load export and TDS levels.

300 1200 5000

270 1000 4000

240 800 3000

210 600

2000 180 400

1000 150 200

120 0 0 0 100 200 300 400 500 600

Figure 5.1 Flow-weighted average TDS, annual solute loads and annual total discharges in the Bow River along the flow path from Lake Louise (0 km) to Ronalane (571km).

5.2.2 Downstream of Calgary The solute load mass balance diagram of the Bow River downstream of Calgary is shown in Figure 5.2. The calculated percentage contributions to the total mass load at Ronalane from four major sources are summarized in a Table 5.3. Discharge increased little because of flow regulation and diversion within this reach of the Bow River and yet both TDS and solute loads increased markedly below Calgary (Figure 5.1). Between Calgary (212 km) and Carseland (302 km), the total annual solute loads of the Bow River increased on average by 306 kt (Figures 5.1- 5.2 and Table 5.2) due to contributions from the Elbow River, the WWTPs in Calgary, and the Highwood River. Solute load mass

balance calculations show the apparent impact from the WWTPs as they discharge 109 kt (Table 5.2 and Figures 5.1-5.2) of wastewater solute annually to the Bow River. Of the 306 kt net solute load increase between Calgary (212 km) and Carseland (302 km), the wastewater effluent accounted for about 27% while over 72% was contributed by the Elbow and the Highwood Rivers. However, at Ronalane (571 km) after irrigation water withdrawals to BRID and EID, wastewater contribution to the total solute load near the river mouth became 9.1% (Figure 5.3). Although diversions also reduce headwater contributions, the Rocky Mountain watersheds including the Elbow and the Highwood Rivers still contributed the majority (84%) of the total solute loads at Ronalane (Figure 5.3).

Agricultural return flows from the constructed irrigation network of canals are drained primarily via prairie tributaries to the Bow River (Bow River Basin Council 2005; AAFRD 2007). As prairie tributaries between Carseland (302 km) and Ronalane (571 km) may be under the influence of agricultural return flows via subsurface flow paths, the negative impact on the water quality of the Bow River could potentially be significant. The calculated total solute load contribution from the prairie tributaries within this reach was 7% (67kt) of the total solute load in the Bow River at Ronalane (571 km) (Figure 5.3). The majority 77% of the 53kt tributary input came from the final reach of the Bow River (Figure 5.2; Table 5.3).

Upon passing the Bassano Dam (diversion point for EID), the Bow River experienced declines in both the total solute load and the total discharge whereas the average TDS continued to increase (Figure 5.1). This pattern of TDS as compared with the solute load and discharge is similar to that of the Bow River downstream from the Bearspaw Dam in northwest Calgary (212 km). The annual water withdrawal of 489 GL at the Bassano Dam (Table 5.2) caused a substantial loss of water at this reach of the Bow River (Chapter 4). Such substantial amount of water withdrawal is equivalent to over 70% of the total annual discharge of the Highwood River (Table 5.2). The opposite trends of TDS versus the total discharge and solute load between upstream and downstream of the

Bassano Dam are evidence of impact from the substantial EID withdrawals during the irrigation season.

Between Bow City (482 km) and Ronalane (571 km), the estimated tributary contributions to the total solute load in the Bow River in Figures 5.2-5.3 is consistent with the trends in Figure 5.1. Unlike the contrast above and below the Bassano Dam, the continued TDS increase here parallels with rises in both discharge and solute load. This condition can result from disproportionate increases between solute load (M) and total discharge (V) causing an elevated ratio (TDS=M/V) between the two parameters. TDS increases between Carseland (302 km) and Ronalane (571 km) could be caused by the estimated 7% (65 kt) of tributary inputs (Figure 5.2; Table 5.3). Having lost 489 GL of water to irrigation at the Bassano Dam, the Bow River downstream of the dam, shallow and wide, was subjected to evaporation in the summer. Lowered water level in the river can also cause augmented hydraulic gradients between the river and the surrounding drainage areas thus increasing subsurface flows carrying high concentrations of dissolved constituents to the river (see also Section 5.6).

LL 47

WID HW R. EID CM -21 217 -148 279

CC Calgary CL Bassano BC RL 728 727 1033 Dam 899 949

Elbow R. WWTPs BRID 79 109 -82

Table 5.3 Estimated total solute loads and unknown sources or sinks along the Bow River. Percentage contributions from the Rocky Mountain headwaters, Calgary’s WWTPs and the prairie reaches were also calculated. Unknown Estimated Sources Total Estimated /Sinks Estimated Estimated Estimated Solute Sources between Headwater WWTPs Prairie Stations Dist. Loads /Sinks Stations Input Input Input (km) (kt) (kt) (kt) (%) (%) (%) LL 0 47 100 0 0 CM 99 279 233 100 0 0 CC 179 728 -42 100 0 0 BN 212 727 490 100 0 0 Elbow R. ~229 79 WID ~229 -21 WWTP 230 109 HW R. 272 217 BRID ~301 -82 CL 302 1033 4 90 10 0 EID 425 -148 BC 482 899 14 89 10 2 RL 571 949 50 84 9 7

Despite the fact that the wastewater effluent in Calgary accounts for less than 10% of the total solute load in the Bow River, it has a profound and persistent impact on the solute load levels in the Bow River. The impact can be inferred from Figure 5.3, which depicts the linear relationship between total solute load and discharge of the Bow River at different locations. The two linear trends have the same slope but were offset by an intercept of approximately 154 kt (Figure 5.3). The Bow River prior to the WWTPs in Calgary has a constant slope of 0.252. The r2 values of 0.9794 and 0.9994 show that the ratio of solute load over discharge is essentially constant throughout the Bow River. A slope of 0.252kt/GL (or 252 mg/L) indicates that for every 1GL increase in river discharge, solute load to the Bow River would proportionately increase by 0.252 kt. Although the slopes of the linear equations seem slightly different with a value of 0.259±0.017 for the Bow River downstream of the Calgary’s WWTPs, the difference can be considered insignificant within the uncertainty range. The estimated intercept

59 difference of 154 kt (Figure 5.3) is similar to the sum of the cumulative solute loads from Calgary’s WWTPs (87kt) and the prairie tributaries (65kt) combined (Figures 5.2-5.3).

1200

2 302 y=0.259x+82.4 (r =0.9794) CL 1000 571 482 RL BC Bow River below WWTP 800 ∆M≅154 kt 179-212 km

600

Bow River above WWTP 400 CM 2 99 y=0.252x-43.8 (r =0.9994) 200 Total Annual Solute Loads (kt)

0 0 0 500 1000 1500 2000 2500 3000 3500 4000

Total Annual Discharges (GL)

The linear relationships in Figure 5.3 show that the amount of solute load transported by the Bow River is controlled dominantly by discharge in the upper watersheds. Natural factors intrinsic to the hydrogeological properties of the Bow River Basin may constrain the mass load to discharge ratio at a constant value reflected by the slopes of the two equations. The offset between the two linear relationships is related to the different amount of mass load inputs between the Rocky Mountains and the prairies in addition to the wastewater contribution from Calgary. On the prairies, mass load inputs to the Bow River are influenced by water sources (tributaries and groundwater) of a different hydrogeological origin within the more saline Interior Plains.

Although the bedrock formations underlying much of the Western Alberta Plains are predominantly terrestrial carbonaceous sandstones of the Tertiary and Cretaceous ages, marine deposits carrying brackish waters occur throughout the Eastern Alberta Plains within the Bearpaw and Foremost Formations (Johnson and Johnson 1992; Hamilton 1999; HCL 2002, 2003, 2007). Furthermore, a recent study by Grasby et al. (2010) showed that groundwater east of the Cordilleran-Laurentide till boundary at Calgary, just

west of Nose Creek, is dominated by Na and SO4 as opposed to Ca and HCO3 west of the till divide.

Secondary evaporites in the tills are common as they supposedly evolve out of reworked bedrock fragments (Wallick and Krouse 1977; Hendry et al. 1986, 1989) that had undergone hydrogeochemical processes such as pyrite oxidation (Van Stempvoort et al. 1994) and ion exchange. Evaporite dissolution in bedrock formation waters as well as in shallow groundwaters of the tills provides the sources of the high TDS waters commonly found throughout the prairies (Last 1989; Last and Ginn 2005). The fact that only small increases in TDS and solute loads were observed downstream of Carseland is explained by the lack of integrated drainage on the flat prairie topography and the semi-arid climatic conditions.

Figures 5.1-5.3 demonstrate that the total solute loads in the Bow River are predominantly controlled by discharge with the majority (84%) of the load originating from the Rocky Mountain watersheds. The wastewater effluents from Calgary (9%) and the prairie tributary waters (7%) (Table 5.3) are responsible for the abrupt and sharp increase in the total solute load in the Bow River from Carseland to Ronalane (302-571 km). The urban wastewater impact from Calgary is responsible for the majority 56% (87 kt) of this 154 kt of solute load increase whereas the prairie tributaries accounted for the remainder 44% (67 kt) of the additional solute load.

5.3 Geochemistry of the Major Ions The unit of mass (kt) for the major ions making up the total annual solute load in the Bow River is converted to mole equivalents (mole-eq) in Figure 5.4. For major changes, mole-eq values allow chemically related ionic species to be identified. With the exceptions of Na and Cl, differences of solute loads between any two distance intervals between Lake Louise (0 km) and Cochrane (179 km) increased as drainage contribution expand cumulatively downstream along the Bow River (Figure 5.4). Increases with distance were observed as the river approaches Cochrane (179 km). Thereafter, riverine mass loads remained constant throughout the Foothills between Cochrane (179 km) and

Calgary (212 km). The ionic loadings of Ca, Mg, HCO3 and Cl reached a maximum at

Carseland (302 km). Downstream of Carseland (302 km), Na and SO4 loads continued to increase while Cl remained constant close to the peak level observed at Carseland (302 km).

10 WWTP Bassano Dam Ca Mg Na 8 HCO 3 SO 4 Cl 6

4 Mole-Equivalent 9 x10 2

0 CL BC RL LL CM CC

0 100 200 300 400 500 600 Distance (km)

Figure 5.4 Variations in the annual mass loads of the six major ions along the Bow River expressed in giga (x109) mole-equivalent. Extrapolation (dotted lines) represents anticipated trends based on the observation that concentrations-flow relationships between Carseland and Cluny are similar.

9 Ca and HCO3 decreased by over 1x10 mole-eq between Carseland (302 km) and Ronalane (571 km) (Figure 5.4). This corresponded to a decrease in Ca by 25 kt and in

HCO3 by 83 kt (Table 5.2). Within the same reach of the Bow River, the Na and SO4 loads continued to increase by as much as 0.48x109 and 0.34x109 mole-eq, equivalent to

11 kt of Na and in 16 kt of SO4 (Table 5.2). Cl and Mg decreased only marginally by about 2 kt and 3kt respectively (Table 5.2). The 2kt (Table 5.2) Cl loss between Carseland (302 km) and Ronalane (571 km) was approximately equal to the amount diverted from the Bow River for irrigation. The nearly constant trend of Cl in Figure 5.4 indicates that agricultural return flow entering the Bow River downstream of the Bassano Dam cannot be effectively traced using Cl.

Given the dominant carbonate lithology of the Rocky Mountains (Hamilton et al. 1999;

Section 2.4, Chapter 2), the close mole-eq association between Ca and HCO3 in Figure

5.4 supports CaCO3 dissolution as a major source of major ions to the Bow River. However, it is important to note that limestone often contains impurities and is usually composed of a mixture of calcite, calcium-magnesium carbonate, and dolomite minerals. In most limestones, calcite contains significant amount of substitution for Ca2+ by other divalent cations, commonly Mg2+, in the crystal lattice (Deer et al. 1992), and the dissolution of the structurally altered calcite is typically not reversible (Hem 1985). This geochemical property is responsible for the process of dedolomitization, where the

dissolution of gypsum or anhydrite (CaSO4) causes increased dolomite solubility as calcite becomes oversaturated (Langmuir 1997; Appelo and Postma 2005). The strongly held hydration shell of the smaller Mg ion contrasts that of the larger Ca ion and makes it more soluble in water. In fact, calcite precipitation in the presence of dolomite dissolution and dedolomitization has been studied extensively (e.g. Reardon et al. 1980; Back et al., 1983; Plummer and Back 1980; Plummer et al. 1990; Saunders and Toran 1994; Cardenal et al. 1994; Sacks et al., 1995; Capaccioni et al. 2001).

9 The pronounced and simultaneous decreases of Ca and HCO3 (1.5-1.7x10 mole-eq) loads in contrast to that of the slightly lowered Mg level (0.4x109 mole-eq) downstream

of the Bassano Dam (Figure 5.4) can be explained by the geochemistry of calcite

precipitation, dedolomitization and gypsum dissolution. Instream precipitation of CaCO3 provides a possible explanation for the previously observed trends. Except for the headwaters at Lake Louise (0 km), which were undersaturated with respect to both calcite and gypsum, the rest of the river was either near equilibrium or supersaturated with respect to calcite (Figure 5.5). The logarithmic solubility constant varies with temperature (0o-27oC) between 1.96 and 2.43 for calcite (see calculation in Appendix C), but remains nearly constant within the same temperature range at -4.6 for gypsum (Figure 5.5) (Langmuir 1997). The equilibrium relationship for calcite and gypsum (3) are derived from (1)-(2):

+ 2+ - CaCO3(s) + H = Ca + HCO3 (1) 2+ 2- Ca + SO4 = CaSO4(s) (2) + 2- - CaCO3(s) + H + SO4 = CaSO4(s) + HCO3 (3)

and log Keq expressions of (1) - (3) can then be represented as:

2+ - + log K(1) = log[Ca ] + log[HCO3 ]/[H ] 2+ 2- log K(2) = -log [Ca ] + log[SO4 ] - + 2- log K(3) = log[HCO3 ]/[H ] + log[SO4 ]

Values of log K(1) and log K(2) at equilibrium (dashed lines) divide Figure 5.5 into four

solubility fields. The fact that SO4 increased with flow distance while Ca and HCO3 decreased (Figure 5.4) can be caused by gypsum dissolution and calcite precipitation (Figure 5.5). The flow downstream of the Bassano Dam in the summer is slow, shallow and subjected to evaporation (see also Chapter 4). Temperature in this part of the river often reaches as high as 20o to 27oC in the summer (Appendix B-I: F2, F10, G2, G3, G10, I2 and I10). Photosynthesis, likely driven by nutrients from Calgary’s WWTPs,

consumes CO2 and causes CaCO3 solubility to decrease (Hem 1985; Hounslow 1995; Langmuir 1997; Appelo and Postma 2004). Hence, calcite precipitation might have

occurred in the Bassano Dam where a sudden decrease of Ca and HCO3 (Figure 5.4) was observed.

-2

C C

o o Rocky Mt. - Calgary

7 5 0 km 2 99 km -3 179-212 km Gypsum Gypsum and Calcite Downstrem of Calgary 302-378 km Supersaturation Supersaturation -4 Downstream of Bassano

4 482-513 km 517 km

-5

-6 Log[Ca]+log[SO ]

Unsaturated Calcite Supersaturation -7

-8 0 1 2 3 4 5 Log[Ca]+log[HCO ]+pH 3

In contrast to the sudden decrease of Ca, Mg and HCO3 after the Bassano Dam, Na and

SO4 continue to increase along the length of the Bow River. The mole-eq association

between Na and SO4 from Carseland to Ronalane (Figure 5.4) suggests additional input

of Na-SO4 water. Recent study confirmed that groundwater in prairie tills east of Calgary are high in Na and SO4 (Grasby et al. 2010) derived from cation exchange and sulfide oxidation (Hendry 1986 and 1989; Van Stempvoort et al. 1994; Grasby 1997). The removal of CaCO3 via precipitation in the river and/or within the dam may partly account for the relatively increased dominance of Na and SO4 ions (Section 5.5). Figures 5.4 and 5.5 provided useful information about the possible sources and fate of the major ions in the Bow River between Lake Louise and Ronalane. The net decrease of the total solute

65 load in the Bow River previously observed at Bow City (482 km) in Figure 5.1 can therefore, be attributed to both irrigation withdrawals and CaCO3 precipitation.

5.4 The Basic Water Types Throughout this chapter, units of concentrations are expressed in milligram-equivalents per liter (meq/L) as it reflects both the molecular weight and the charge of ions. The relationship between water chemistry and its lithological sources can be more appropriately shown with this unit since ionic solutes in concentrations of meq/L are chemically equivalent, and the total meq/L of anions would equal the total meq/L of cations. The electroneutrality of the water, represented by 2mCa2+ + 2mMg2+ + mNa+ + + - 2- - mK = mHCO3 + 2mSO4 + mCl where m denotes molar concentrations, must be satisfied.

Scatter Plots

The Bow River headwater was characterized as Ca-Mg-HCO3-SO4 type based on the relative dominance of major ions in percentages (Grasby 1997; Grasby and Hutcheon 2000). In order to detect the stoichiometric and chemical relationships among the major ions, six scatter diagrams were plotted in Figure 5.6 to show correlations among the

different combinations of cation-anion pairs. Figure 5.6a shows HCO3 is in excess with respect to Ca as most points lie below the 1:1 charge equivalence line. By balancing the excess HCO3 with Mg, the new cation pair in Figure 5.6b shows that the combined Ca

and Mg is in excess of HCO3. By adding SO4 in combination with HCO3 in Figure 5.6c, the excess cation in Figure 5.6b was mostly balanced. Data points that shifted to the 1:1 line have near perfect correlation between the ionic combinations of Ca+Mg and 2 HCO3+SO4. The fitted regression: y = 1.0349x – 0.0101 (n = 42, r = 0.9915) in Figure 5.6c for waters from upstream of Calgary (0-212 km) proves the excellent correlation and

shows that Ca, Mg, HCO3 and SO4 are the dominant constituents of major ions in the Bow River upstream of Calgary. The Bow River’s chemical composition upstream of the Bassano Dam (0-378 km) rests mainly on or slightly above the 1:1 line, but downstream of the dam (482-571 km), it deviates below the 1:1 line (Figure 5.6c).

a/b Calgary b/w Calgary b/w Bassano Dam 0 km 248 km 482 km 99 km 302 km 513 km 179 km 378 km 571 km 212 km

7 b 7 a

6 6

1:1 5 5 1:1

4 4

3 3 Ca (meq/L) Ca+Mg (meq/L) 2 2

1 1

0 0 0 1 2 3 4 5 6 7 0 1 2 3 4 5 6 7

HCO3 (meq/L) HCO3 (meq/L)

7 c 8 d

6 7

5 1:1 6 1:1

4 5

3 4 Ca+Mg (meq/L)

2 (meq/L) Ca+Mg+Na 3

1 0 - 212 km: 2 y = 1.0349x - 0.0101 (n = 42, r2 = 0.9915) 0 1 0 1 2 3 4 5 6 7 1 2 3 4 5 6 7 8

HCO +SO (meq/L) HCO3+SO 4 (meq/L) 3 4

2.0 e 7 f

6 1.6 1:1 Wastewater Plume: 5 231 - 248 km

1.2 4

3 0.8 Na (meq/L)

2 1:1

0.4 Ca+Mg+Residual Na(meq/L) 1 2 y = 1.0535x - 0.2246 (n = 20, r2 = 0.971) y = 1.0226x + 0.0616 (n = 118, r = 0.9891) 0.0 0 0.0 0.2 0.4 0.6 0.8 1.0 0 1 2 3 4 5 6 7

Cl (meq/L) HCO +SO (meq/L) 3 4 Figure 5.6 Scatter plots showing the various combinations of cations against anions for the Bow River water and their correlations with respect to the 1:1 charge equivalence line.

By adding Na to Ca+Mg in Figure 5.6d, all the points were shifted to above the 1:1 line except for the Rocky Mountain headwater samples at 0 and 99 km. This outcome was expected as the headwater Na concentrations were low (<0.08 meq/L). Before an attempt to correct for the excess cations was made, Figure 5.6e was plotted in order to assess the degree of correlation between Na and Cl. In Figure 5.6e, Na and Cl were well correlated in a linear trend slightly above the 1:1 line for the wastewater plume in the Bow River from 231-248 km with a fitted linear equation of y = 1.0535x + 0.2246 (n =20, r2 = 0.971). The small amount of excess Na expressed by the equation’s intercept offset with the 1:1 line (0.09-0.26 meq/L) is insignificant within the ±5% tolerance range for the chemical measurement uncertainty.

The Bow River water downstream of the Bassano Dam contained Na levels that placed the data point above the 1:1 line (Figure 5.6e). Based on the excellent Na-Cl correlation in Figure 5.6e, the fact that Na and Cl occur in sewage (Vandenberg 2005; Iwanyshyn et al. 2008), in precipitation as dissolved sea salt aerosols (< 0.003 meq/L) (Appelo and Postma 2007), and that road salt is the primary de-icing agent used in urban areas during winter, the Na-Cl correlation in Figure 5.6e is reasonable. The result of this manipulation allowed for the residual Na, unbalanced by Cl, to be calculated. The residual Na was combined with Ca+Mg in Figure 5.6f and a near perfect correlation along the 1:1 line was, at last, attained for the Bow River water from the headwaters to the mouth. The fitted regression: y = 1.0226x + 0.0615 (n = 120, r2 = 0.9891) (Figure 5.6f) is proof of this excellent correlation.

A comparison between Figures 5.6d and e revealed that the Bow River water from downstream of Calgary was elevated in Na. A part of this Na came from Calgary’s wastewater containing Na-Cl water whereas the remainder was related to SO4 as already demonstrated in Figure 5.4. Given that groundwater in prairie tills east of Calgary contained are high in Na and SO4 (Grasby et al. 2010), Na-SO4 contribution from prairie waters is a very likely cause of the excess Na found in the Bow River water downstream of Calgary.

Durov Diagram Percentage distribution of the major ions was evaluated using ternary diagrams with a projection field. Piper diagrams are commonly used in water analysis and interpretation but the 60o projection angle causes substantial overlapping of water types, reducing the potential nine water types to four. Excessive overlapping of water characteristics can be improved by using a Durov diagram whose 90o projection angle allows all possible water types to be separated. Detailed discussion of Durov diagrams can be found in Zaporozec (1972), Freeze and Cherry (1979), and Lloyd and Heathcote (1985).

The Bow River water chemistry prior to the WWTPs in Calgary was different from that

downstream of the city. The water chemistry changed from a Ca+Mg-HCO3 type in the

Rocky Mountains to a water type that is increasingly Na-SO4-Cl enriched (Figure 5.7). Highly elevated Cl concentrations were an exclusive characteristic of the wastewater effluent at Calgary (Figure 5.7 crosses), whereas elevated SO4 (Figure 5.7 dotted open squares) was not unique to the wastewater. Many tributary waters on the prairies

contained SO4 concentrations similar to or higher than those in the wastewaters

(Appendix B-II: K1-7; L1, 2, 5-7; M1-3; N2-4; O1-5; P1-6; Q2-4; S1-5). The SO4 concentrations of the TPBB and TPFC were typically 2-6 times higher than those in the Bow River upstream of the WWTPs, but the Cl concentrations in the wastewater effluents were over 20 times greater (Appendix B-III: T1-3; U1-3).

The Cl concentrations for the prairie tributaries ranged from 4 to 10 mg/L but can increase occasionally to 15-20 mg/L (Appendix B-II). The Crowfoot Creek has the highest Cl concentrations among all prairie tributaries with concentrations ranging from 14 to 40 mg/L (Appendix B-II: K1-7). The cumulative impact from the prairie tributaries

high in SO4 within the ranges of 700-7000 mg/L (Appendix B-II: K3-6; M1-3) and 125 245 mg/L (Appendix B-III: T1-3; U1-3) could potentially have a stronger influence on the downstream Bow River water chemistry than the wastewaters since annual discharge from WWTPs is only about 4-5 times that of the Crowfoot Creek.

The compositions of the prairie tributary waters were distinct from the Bow River waters and could be categorized into two types in Figure 5.7. A group of tributary waters was dominated by Na and SO4 (CF Ck., E1716 and square symbols) plotting towards the centre-right corner of the projection field, whereas the other group was characterized by elevated Mg instead of Na (E1413 and circular symbols) plotting between the Bow River

water and the Na-SO4 water. The tributary waters with elevated Mg-SO4 contained 40

60% Mg, 20-40% Ca, 10-30% Na, 40-45% SO4 and 40-55% HCO3 whereas the ones

dominated by Na-SO4 had 30-80% Na, 30-40% Mg, 10-30% Ca, 50-95% SO4, and 5-40%

HCO3 (Figure 5.7). The Na-SO4 waters were from tributaries located on the western side of the Eastern Alberta Plains (Figure 2.1, Chapter 2) near Bassano and Bow City. The

Mg-SO4 waters occur in the final reaches towards the eastern side of the Eastern Alberta Plains near the towns of Scandia, Taber and Ronalane (503-571 km). Despite the compositional differences between these two types of tributary waters, the small amounts of Cl <10% was a universal characteristic among all tributaries waters and the Bow River waters upstream of the WWTPs in Calgary.

The wastewater effluent from both WWTPs consisted of approximately 30% Ca, 35% Mg and 35%Na showing no dominant cation (Figure 5.7). For the anions, TPFC’s

effluent was composed of approximately equal proportions (30-35%) of HCO3, SO4 and

Cl (Figure 5.7). In contrast to TPFC, wastewater effluent from TPBB showed Cl+NO3 being a dominant anion combination (40-50 %), of which 1/3 is NO3 (Appendix B-III:

T1-3). The NO3 levels of TPFC ranged from 0.05 to 0.4 mg/L whereas NH4 (~30 mg/L)

was the dominant form of nitrogen discharged by TPFC (Appendix B-III: T1-3; U1-3).

Based on the graphical interpretation using the Durov diagram, four water types characterizing the sources of Bow River water were separated and identified. They

included the Ca-Mg-HCO3 water of the Rocky Mountains, the Cl+NO3 containing

wastewater effluent in Calgary, the Na-SO4 tributary waters on the western side of the

Eastern Alberta Plains and the Mg-SO4 tributary waters within the final reaches of the

Bow River. It was visually apparent from Figure 5.7 that the Bow River water downstream of Calgary (>302 km) plotted between the wastewater plume and the tributary waters suggesting mixing of these three water types with the headwater composition.

Figure 5.7 Durov diagram showing the range of anion and cation compositions (eq%) of waters from the Bow River, the prairie tributaries and the treated wastewater effluents from Calgary.

5.5 Tracing Chemical Variations with Ion Ratios The characterization of water types was accomplished using scatter plots and a Durov diagram (Section 5.4). Water type classifications convey general information about the chemistry of waters but not the chemical relationships among the major ions. Compositional differences among water types can be evaluated using ion ratios to provide further insight into the causes of chemical variations in the Bow River. In Figure

5.8, Ca/Mg, Na/Ca and HCO3/SO4 ratios were used to trace chemical changes along the Bow River at different sampling locations. The ion ratios of Calgary’s wastewater and the prairie tributary waters were also evaluated to help elucidate the sources and cause of chemical variation in the Bow River.

5.5.1 The Rocky Mountain Headwaters Water-rock interaction influences the chemical composition of the Bow River. For the headwaters at Lake Louise (0 km), ratios of Ca/Mg (1.5) (a) and Na/Ca (<0.2) (b)

remained constant while those of HCO3/SO4 varied between 5.0 and 6.5 (Figures 5.8). Ion ratios in Figure 5.8 show that the chemical composition of the headwater is not uniform but rather undergoes changes with flow distance from Lake Louise (0 km) to

Canmore (99 km). Ca/Mg ratios had increased from 1.5 to around 2.0 while HCO3/SO4 ratios decreased from between 5.6 and 6.5 to between 2.0 and 4.5 (Figure 5.8). In addition, water sampled at 179 and 212 km carried Ca/Mg ratios similar to, and

HCO3/SO4 ratios higher than those at 99 km (Figures 5.8). These changes in the Ca/Mg

and HCO3/SO4 ratios revealed a chemical shift towards Ca-SO4 in the Front Ranges

followed by a shift back to Ca-HCO3 in the foothill and upland regions. This chemical transition coincides with lithological variations in the Rocky Mountains and corroborates the previous finding (Section 5.3) that calcite-gypsum solubility plays an important role in controlling the major ion chemistry of the Bow River. Discussions about carbonate and gypsum dissolution and ion-exchange reactions in the Bow River can also be found in Grasby (1997), and Grasby and Hutcheon (2000).

2.5

Bow River Front Ranges - AB Uplands 0 km West - Eastern Plains 99 km 2.0 179 km 212 km 302 km 482 km 571 km 1.5 WWTP

Tributaries CF Ck. E1717

Ca / Mg 1.0 E1716 E1616 E1415 E1413 (12 Mile Ck) 0.5 WID + BRID B1516 B1416 (NW Coul.) B1212

0.0 0 1 2 3 4 5 6 7 HCO / SO 3 4

3 WID + BRID a

2 Na / C

1 EID

0 0 1 2 3 4 5 6 7

HCO / SO 3 4

5.5.2 Prairie Tributaries and Calgary’s Wastewaters Variations in the water chemistry of the prairie tributaries can be differentiated using ion ratios. Water in E1716 and those sampled from WID and BRID tributaries show low

Ca/Mg and HCO3/SO4 ratios ≤1, but Na/Ca ratios were high between 1 and 4 (Figure

5.8). Ion ratios revealed that Na and SO4 are the dominant ions in these tributary waters that are high in TDS between 500 and 2500 mg/L (Figure 5.9). For waters from EID

tributaries with TDS <500 mg/L (Figure 5.9), Ca/Mg and HCO3/SO4 ratios are >1 and

Na/Ca < 1 (Figure 5.8). Ion ratios confirmed that Ca and HCO3 are the dominant ions in tributary waters draining through EID.

3.5 WID CF Ck. 3.0 EID E1717 E1716 2.5 E1616 E1415 E1413 2.0 BRID B1516 /SO 3 4 B1416 1.5 B1212 HCO

1.0

0.5

0.0 0 500 1000 1500 2000 2500 3000

TDS (mg/L)

Calgary’s wastewater, with Na/Ca ratios ≥1, Ca/Mg ratios >1, and HCO3/SO4 ratios around 1 (Figure 5.8), revealed that Na was the dominant cation followed by Ca but

neither HCO3 nor SO4 was dominant (see also Figure 5.7). Ion ratios of the Bow River throughout the prairies are intermediate between those of the headwaters(0-212 km), and those of the prairie tributaries (302-571 km) and Calgary’s wastewater (Figure 5.8).

These chemical variations were difficult to discern in detail using scatter and Durov diagrams (Figures 5.6-5.7). Evaluation using ion ratio diagrams helps to ascertain that the Bow River’s major ion chemistry downstream of Calgary is under the influence of mixing with water sources having distinct chemical characteristics. They include prairie

tributary waters of Na-Mg-SO4 and Ca-Mg-HCO3 types, and Calgary’s wastewater effluents of Na-Ca-Cl type. Figures 5.8-5.9 confirm that some prairie tributaries, especially those draining through BRID, contributed to increased Na and SO4 load in the Bow River downstream of Calgary.

5.6 Seasonal Variations of Ion Ratios Temporal variations of ion ratios were used to help identify seasonal influences on the water chemistry of the Bow River. At Canmore (99 km), Cochrane (179 km), Calgary

(212 km) and Carseland in May and June of 2008, Cl/SO4 and Na/Ca (Figure 5.10a-b) ratios peaked. For spring Na-Cl peaks, road salt runoff is the most probable cause given that the timing coincided with snowmelt and rainfall period. Previous work showed that the river-connected alluvial aquifer in the Calgary region is susceptible to contamination (Manwell and Ryan 2006) and a later study discovered that Na and Cl levels increased in the Bow River with increased baseflow discharge (Iwanyshyn et al 2008). The spring Na-Cl peaks in Figure 5.10a-b suggest that road salt use by municipalities other than Calgary within river basin may be linked to increased Na and Cl levels in the Bow River via spring runoff and potentially discharge with baseflow.

During the transition from peakflow to early baseflow (June-September), HCO3/SO4 and Ca/Mg ratios decreased in the Bow River downstream of Lake Louise (0 km) (Figure 5.10c-d). The baseflow period from October to April is characterized by increasingly higher HCO3/SO4 and Ca/Mg ratios (Figure 5.10c-d). The ion ratio variation showed a

shift in the baseflow chemistry towards higher levels of Mg and SO4 from late summer to early fall before Ca gains dominance over Mg from late fall to early spring. The transition from winter-spring baseflow to summer peak flow is marked by increases in

HCO3/SO4 ratios (Figure 5.10c) and decreases in Ca/Mg ratios (Figure 5.10d), suggesting

summer flow was relatively higher in Mg and HCO3 than the winter baseflow.

Ion ratios at Lake Louise (0 km) showed little seasonal variation (Figure 5.10), suggesting that the source water from these high elevation mountain ranges of exposed bedrocks and poor soils has a uniform chemical composition. In contrast, Front Ranges have well developed soil zones (see Section 2.5; Chapter 2). Temporal patterns in Figure

5.10c and d show elevated Ca/Mg and decreased HCO3/SO4 ratios during the baseflow

period. Increased Ca and SO4 levels during the baseflow period indicate evaporite dissolution in groundwaters (Figure 5.10c-d) downstream of Lake Louise. From July to September and in May, the Bow River water on the prairies (302-571 km) had low

Ca/Mg and HCO3/SO4 ratios and high Na/Ca ratios (Figure 5.10 b-d). The variation in ion ratios may be small in the headwaters but the overall pattern of Na/Ca, Ca/Mg and

HCO3/SO4 ratios are similar throughout the Bow River downstream of Lake Louise. The

extent of Na/Ca, Ca/Mg and HCO3/SO4 variations were greatest in river water downstream of the Bassano Dam.

Given that solubility of calcite decreases with increasing temperature (Langmuir 1997; Appelo and Postma 2005), calcite supersaturation in waters with temperature >5oC could occur (see also Figure 5.5). Bow River flow on the prairies (302-571 km) was low from July to September 2007 and in May 2008 due to flow regulation and irrigation withdrawal (see also Figures 4.3-4.4, Section 4.3, Chapter 4). Water temperature downstream of the Bassano Dam had actually reached as high as 27oC in the summer (Appendix B-I: G2), which was 10-13oC higher than those upstream of Calgary. Hence, calcite precipitation in the Bow River (see also Section 5.3) in the summer and the

discharge of Na-Mg-SO4 tributary water are causes of riverine chemical variation.

Figure 5.10c-d shows that enrichment of Na and SO4 in the Bow River was highest from July to September downstream of the Bassano Dam during the later part of the irrigation season when water withdrawal was high and river flow was low. Lowered river stage can

alter hydraulic gradient in a drainage system and potentially induce increased subsurface flow or groundwater discharge to the river (see also Section 5.2.2). The proposed

mechanism could be important in causing increased Na, Mg and SO4 loads to the Bow

River, especially downstream of the Bassano Dam because Na-Mg-SO4 type groundwater is common on the eastern part of the prairies in Alberta (HCL 2007), and increased Na and SO4 levels did occur during low flow in the summer. The validity of this hypothesis however, remains to be investigated in future studies.

a b

0 km 302 km 99 km 482 km 1 179 km 571 km 1 212 km 4 0.1 0.1 Na / Ca Na / Cl / SO

0.01 0.01 5/1/2007 8/1/2007 11/1/2007 2/1/2008 5/1/2008 8/1/2008 5/1/2007 8/1/2007 11/1/2007 2/1/2008 5/1/2008 8/1/2008 Date Date

c d

8 2.2

6 2.0

4 1.8 / SO 3 4

Ca / Mg 1.6

HCO 2

1.4

1.2 5/1/2007 8/1/2007 11/1/2007 2/1/2008 5/1/2008 8/1/2008 5/1/2007 8/1/2007 11/1/2007 2/1/2008 5/1/2008 8/1/2008 Date Date

5.7 Summary The Bow River discharged ≤3500x109 L of water to the South Saskatchewan River in 2007 and 2008. Average TDS along the river increased from 150 mg/L at Lake Louise to 290 mg/L at Ronalane. The total annual solute loads of the Bow River, controlled mainly by discharge, increased by about 20 fold from headwater to mouth. The majority 84% of the total annual solute load originated from the Rocky Mountain watersheds while about 9% came from Calgary’s WWTPs and up to 7% was contributed by prairie sources. The

major ion chemistry of the Bow River is of Ca-Mg-HCO3-SO4 type. However, the river’s chemical composition is not uniform but rather varies with flow distance and season. During the baseflow period from August to April, groundwater containing dissolved

gypsum in the Front Ranges of the Rocky Mountain contributed to elevated Ca and SO4 levels in the river. During the snowmelt and rainfall period in May and June as river flow transitioned from baseflow to peakflow, Mg and HCO3 increased relative to Ca and SO4.

Na and SO4 in the Bow River increased throughout the prairies east of Calgary but the extent of the increase was most noticeable downstream of the Bassano Dam in May and from July to September when river flow was low due to flow regulation and irrigation withdrawal. Calcite precipitation, driven by high water temperature and photosynthesis

in the summer could lower Ca and HCO3 levels in the river and contribute to relative

enrichment of Na, Mg and SO4. Prairie tributary water of Na-Mg-SO4 type, high in TDS between 500 and 3000 mg/L, is an important source to elevated Na and SO4 in the Bow

River. Contribution from wastewater derived SO4 in Calgary appeared to be less important than the prairie sources.

The water chemistry of prairie tributaries was either of Ca-Mg-HCO3 type with TDS

<500, or of Na-Mg-SO4 type with TDS >500 mg/L. Calgary’s wastewater effluent is of

Na-Ca-(Cl+NO3) type but the Na-Cl peaks from the snowmelt and rainfall period in May and June suggest also road salt runoff. Chemical compositions with variably elevated

Na, Cl, SO4 and NO3 levels along the flow distance showed that the Bow River is also a mixture containing at least three more source waters in addition to the Rocky Mountain

headwaters. The chemical data showed that the major ion chemistry of the Bow River was influenced by calcite precipitation, gypsum dissolution, and wastewater and prairie tributary discharge.

Anthropogenic impact on the water quality of the Bow River is evident in elevated Cl and

NO3 concentrations downstream of Calgary. Although not a dominant ion in the Bow

River, NO3 concentrations downstream of Calgary greatly exceeded those in the river upstream of Calgary. In order to determine the extent of wastewater impact on causing elevated SO4 and NO3 loads in the Bow River, the sources, fate, and transport of SO4 and

NO3 should be examined. Interpretation of isotopic compositions of SO4 and NO3 with chemical and hydrometric data in the subsequent two chapters will further enhance the understanding about the interaction between the geochemistry of the Bow River and the superimposed anthropogenic effects.

CHAPTER 6: THE SOURCES OF SULPHATE IN THE BOW RIVER

6.1 Introduction 2- Sulphate (SO4 ) the oxidation product of elemental S, sulfide minerals and organic

sulphur, is ubiquitous in the environment. In the atmosphere, SO4 is commonly derived from a mixture of natural sea spray aerosol, biological releases of S compounds and anthropogenic emissions such as burning of fossil fuel and coal (Krouse and Grinenko

1991). In the hydrosphere, SO4 mainly originates from lithospheric evaporite dissolution

or sulfide oxidation. Atmospheric contribution of SO4 to a watershed is controlled by

groundwater infiltration and is usually a relatively minor component of riverine SO4 compared to those derived from the lithosphere. In the limestone-dolostone dominated watersheds of the BRB in the Rocky Mountains, association between calcite-gypsum solubility and the water chemistry of the Bow River was discussed in Chapter 5. On the prairies where irrigation on glacial till is a major land use activity of the region, the

chemical composition of the Bow River evolved increasingly towards a Na-SO4 type water (see Chapter 5). It can therefore be hypothesized that Bow River SO4 throughout the prairie reaches is influenced by at least two different sources. As much of the

discussion about gypsum dissolution in the Rocky Mountains as a SO4 source had been covered in Chapter 5, emphasis on the prairie SO4 sources is given in the rest of the introduction.

The interior plains of Alberta constitute a part of the Western Glaciated Plain, one of the

largest SO4 rich lands in the world (Broughton 1984; Last and Slezak 1987; Garret 2001). The brines of the estimated 5.5 million saline basins in this region are predominantly of sodium sulphate type (Last and Slezak 1987; Garret 2001) and in the typical clayey till

settings, SO4 contamination of ground and surface waters and soil salinization are common. Salinization caused by prolonged accumulation of SO4 salts in the soil can affect the productivity of the agricultural lands. Because of the common occurrence of sulphate in the dark brown and brown chernozemic soils (Figure 2.3; Chapter 2), the dominant soil type of the southern Alberta prairie (Government of Alberta 2001),

synthetic sulphur fertilizers in Alberta are not widely used and cannot be considered a significant source of sulphate. Other forms of anthropogenic sulphate released into the environment generally include burning of fossil fuels, discharges of household wastes, detergents and releases of industrial effluents and emissions are also still common (USEPA 2003).

The sources and occurrences of sulphate on the northern Great Plains have been studied extensively since the 1900’s after the discovery of the abundant and wide spread

commercial deposits of high purity Na2SO4 salts (secondary evaporite minerals), but debates and uncertainty still remain regarding the origin and genesis of this economic mineral. Early researchers such as Rueffel (1968) and Grossman and Hartford (1968) emphasized that the buried pre-glacial bedrock valleys on the prairies controlled the

distribution of this salt. A formation mechanism for these massive reservoirs of Na2SO4 salts was proposed by Grossman and Hartford (1968) who suggested that paleo groundwaters that had started dissolving bedrock evaporites since the late Devonian began draining into lakes via integrated glacial melt-water channels by the late

Pleistocene. The integrated paleo-drainage systems then allowed high purity Na2SO4 crystals to form under preferential freeze segregation in the winters and cold evenings when temperatures fell below 0oC while the residual brines carrying other dissolved ions drained towards the southeast into the ocean via the Missouri River (Grossman and

Hartford 1968). A conceptual model for the preservation mechanism of these Na2SO4 deposits was also proposed. It was suggested that as climate warmed and aridity increased, the drainage pattern gradually disintegrated into isolated basins leaving permanent Na2SO4 deposits buried and preserved under extinct paleo-lakes (Grossman and Hartford 1968). This hypothesis was partially dismissed by Last and Slezak (1987) based on incompatible chemical compositions between the bedrock brine and the Paleozoic evaporites.

An early isotopic investigation by Wallick and Krouse (1977) on groundwater generated

Na2SO4 deposits in Alberta provided an alternative explanation for sources of the prairie

sulphate. Variations in the isotopic values of sulphate suggested that oxidation of pyrite in the Cretaceous shales and the dissolution of gypsum from bedrock fragments incorporated in the glacial tills gave new insight into the sources of sulphate on the prairies (Wallick and Krouse 1977). The suggestion regarding bedrock fragment derived

SO4 in the tills was in agreement with findings by Hendry et al. (1986, 1989), but the importance of pyrite oxidation was disputed. Hendry et al. (1986) considered organic S in the tills as the primary form of reduced S and the oxidation of the organic S the source 2+ of the till SO4 (Hendry et al. 1986). This conclusion was reached on the basis of low Fe concentrations (<2ppm), a negligible amount (<0.01%) of pyrite, undetectable amounts of sulphate reducing bacteria, and low (35%) recovery of oxidisable sulphur using the peroxide-oxidisable sulphur method.

A later study by Van Stempvoort et al. (1994) refuted the conclusion reached by Hendry

et al. (1986, 1989) emphasizing that pyrite oxidation was the primary source of SO4 in the weathered tills. The basis of the opposing view put forth by Van Stempvoort et al. (1994) was grounded in a different laboratory technique (Cr-reducible sulphur method) for estimating the inorganic form of reduced S, claimed as being mainly pyrite. Van Stempvoort et al. (1994) suspected that errors in determining reduced inorganic S using the peroxide-oxidisable S method by Hendry et al. (1986) could be significant when interferences from gypsum and organic matter were present (Sullivan et al. 1999). The large amounts (65-90%) of the inorganic form of reduced S separated from the total reduced S suggested that the amount of pyrite calculated by Hendry et al. (1986) might have been underestimated. Other isotopic studies also deemed pyrite oxidation an important mechanism for explaining the origin of sulphate in the weathered tills (e.g. Keller and Van der Kemp 1988; Keller et al. 1991; Dowuona et al. 1992; Fennell and Bentley 1998).

In addition to studying the origin of till S, Hendry et al. (1986) proposed a mechanism to explain the redox partitioning of S species between the weathered and non-weathered zones of the tills. Based on a groundwater flow model, Hendry et al. (1986) suggested

that prolonged water table decline during the dry and warm Altithermal period from 11,000 to 3000 years BP was responsible for the extent of sulphur oxidation observed in the present-day weathered zone of the tills. As for the present-day distribution and

mobility of SO4 in the tills, Keller and Van der Kamp (1988) and Van Stempvoort et al.

(1994) claimed that SO4 dynamics in the tills are dictated by the variable regional permeabilities and microtopographic expressions.

Hydrogeological properties of a river basin control the rate of solute export from land to

rivers. Given the abundant SO4 sources throughout the Bow River Basin, occurrences of

SO4 in the Bow River are expected. Some aspects of SO4 such as the role of gypsum

dissolution in the Rocky Mountains and SO4 enrichment downstream of the Bassano Dam had already been discussed in Chapter 5 based on chemistry data. In this chapter, direct evidence for SO4 sources and their relative contributions to the Bow River may

enhance the understanding of the origin and the fate of SO4 in the Bow River. Sulphate in the Bow River near the mouth contains contributions from the Rocky Mountains, the wastewater of municipalities and the prairie tributaries in various proportions. A mixture

of natural and anthropogenic SO4 derived from bedrocks, tills, soils and Calgary’s

wastewaters are likely the major sources of SO4 in the Bow River. This chapter utilizes

the isotopic composition of SO4 to assist in the differentiation of natural and

anthropogenic sources of SO4 in the Bow River. The objective of Chapter 6 is to

determine sources of SO4 in the Bow River and assess the importance of wastewater SO4 with respect to the prairie sources.

6.2 SO4 in the Bow River 6.2.1 Concentration-Flow Relationships

The SO4 concentration-flow relationships of the Bow River are shown in Figure 6.1. The Bow River in the Main Ranges at Lake Louise (0 km) had near constant and low

(<20mg/L) SO4 concentrations independent of flows (open squares) whereas at all other

downstream sites (99-571 km), Bow River SO4 concentrations decreased with increasing flows. The fact that there are three inverse relationships representing different reaches of

the river in Figure 6.1 suggests SO4 in the Bow River has more than one dominant

source. Elevated SO4 concentrations between 25 and 50 mg/L at Canmore (99 km) (curve 1; Figure 6.1) corresponded to waters affected by gypsum dissolution in the Front

Ranges (Sections 5.3-5.6; Chapter 5). Except for increased flows, the range of SO4 concentrations throughout the upland reaches between Cochrane and Calgary (79-212 km) (curve 2; Figure 6.1) were the same as those (20-50 mg/L) at Canmore (99 km). Downstream of Calgary throughout the prairie reaches from Carseland to Ronalane (302 571 km) (curve 3), the range of flows (50-150 m3/s) were similar to those of the 179-212

km reach, but the SO4 concentrations were significantly higher ranging between 40 and 130 mg/L (Figure 6.1). In particular, four samples from downstream of the Bassano Dam

(>425 km) had noticeably higher SO4 concentrations with concentrations of >110 mg/L under minimum flows (<50 m3/s), and >50 mg/L under maximum (>350 m3/s) flows.

140 0 km 99 km 120 179 km 212 km 302 km 100 482 km 571 km

80 (mg/L)

4 60

SO 3. y = 37+332e-x/24.2 (n=10, r2=0.94) 40

2. y = 27+44e-x/56.4 (n=10, r2=0.97) 20 1. y = 26+33e-x/36.4 (n=10, r2=0.88)

0 0 100 200 300 400 500

Flow (m3/s)

Figure 6.1 SO4 concentration-flow relationships along the Bow River from Lake Louise (0 km) to Ronalane (571 km).

6.2.2 Seasonal Variations along the Bow River

Variations of the seasonal SO4 concentrations along the Bow River are shown in Figure 6.2 as monthly spatial trends (a) and temporal trends at different sampling sites (b). With the exception of samples from the snowmelt and rainfall period in May and June 2008,

SO4 concentrations increased from Lake Louise (0 km) through Calgary to Carseland

(302 km) and remained relatively constant with only slight increases (Figure 6.2). SO4 concentrations increased the most between Lake Louise (0 km) and Canmore (99 km) and between Calgary (212 km) and Carseland (302 km) (Figure 6.2). SO4 concentrations at Cochrane (179 km) were generally lower than at Canmore (99 km) but in June and July of 2007, they increased along the length of the river from Lake Louise (0 km) to

Cochrane (179 km) (Figure 6.2). From June to October in 2007, SO4 concentrations varied little downstream of Carseland (302 km) except for small increases at Scandia

(513 km) and Ronalane (571 km) (Figure 6.2). From summer to mid fall, SO4 concentrations of the Bow River on the prairies (302-571 km) were usually between 40 and 50 mg/L (Figure 6.2).

Baseflow SO4 in late fall (Nov07) and early spring (Apr08) increased. In May 2008, SO4 concentrations in the Bow River downstream of the Bassano Dam became highly

elevated towards 140 mg/L (482-571 km; Figure 6.2). Riverine SO4 concentrations downstream of Carseland (302 km) were generally constant even during baseflow periods

(Nov07 and Apr08) but in spring (May08 and Jun08), SO4 concentrations increased continuously with flow distances from Carseland (302 km) to Ronalane (571 km) (Figure

6.2). During early snowmelt period in May 2008, SO4 concentrations even reached the maximum level of 140 mg/L at Ronalane (571 km) (Figure 6.2). During peakflow in

June 2008, SO4 concentrations were overall lower (Figure 6.2a) than those in May 2008, although the two spatial trends are similar. These observations suggest that prairie

contributions to SO4 load in the Bow River were most significant downstream of Carseland (302 km) in spring. This is consistent with findings in Chapter 5 - Section 5.6.

200 WWTP Bassano Dam

RL SD BC Spring 100 Jun08 CN May08 CL Apr08 CM CC Fall 50 Nov07 Oct07 (mg/L) (mg/L)

4 Sep07 SO Summer Aug07 Jul07 LL Jun07

10 0 100 200 300 400 500 600 Distance (km)

140 0 km 99 km 179 km 120 212 km 302 km 378 km 100 482 km 571 km

80 (mg/L)

4 60 SO

0 6/1/2007 9/1/2007 12/1/2007 3/1/2008 6/1/2008 9/1/2008 Date

Figure 6.2 Plots for a) SO4 concentrations along the length of the Bow River from Lake Louise (0 km) to Ronalane (571 km) and b) variations in the monthly SO4 concentrations.

Water samples with highest SO4 concentration above curve 3 in Figure 6.1 were from the spring in May08 and Jun08 at Bow City (482 km) and Ronalane (571 km). Given that the SO4 concentration maxima occurred downstream of Carseland (302 km), SO4 inputs other than Calgary’s wastewaters must be considered responsible for the increases. Instream evaporation in spring is minor and cannot induce a substantial increase in the

river’s solute concentrations as observed in Figure 6.2. Under the influence of constant

wastewater discharge of 23kt/yr (63t/day) of SO4, SO4 concentrations in the Bow River would decrease in the case of increasing flow or increase in the case of decreasing flow had inputs from the prairies been negligible. The fact that flow in the Bow River increased from May to June, and that flow between Carseland and the Bassano Dam remained nearly constant (Figure 4.3; Chapter 4) are clear indications that contributions

from the prairies to elevated riverine SO4 levels was significant. This is also true for the

Rocky Mountains and elsewhere in the Bow River where the SO4 concentration increased.

6.2.3 Tracing Mass Loads of SO4 along the Bow River

The mass loads of SO4 along the Bow River are shown in Figure 6.3a. Given Cl is conservative and the prairie tributaries are not a significant source of Cl (Chapter 5), the

SO4/Cl mole equivalent ratios in Figure 6.3b can be used together with mass load values

to trace Calgary’s wastewater SO4 in the Bow River. The mass balance flow chart in Figure 6.4 and Table 6.1 provides quantitative estimates explaining variations in the mass loads of SO4 observed in Figure 6.3.

The total annual mass loads of SO4 increased with flow distance along the Bow River (Figure 6.3a). The largest increase (>100 kt) was the mass load difference between Lake Louise (0 km) and Cochrane (179 km) (Figure 6.3a). After the Bow River exited the

mountains and entered the plains, riverine SO4 load remained constant at around 107 kt until upstream of the WWTPs (179-212 km) (Figure 6.3a). Downstream of Calgary at

Carseland (302 km), the riverine SO4 load increased to 157 kt.

The SO4/Cl ratios of the wastewater effluents were low around 1.4±0.4 but upon mixing

with river water, SO4/Cl ratios within the wastewater plume at 248 km increased to around 3.4±1.1 (Figure 6.3b). The trend shown in Figure 6.3b suggests that once the

wastewater was evenly mixed across the river channel, the SO4/Cl ratio would likely have been around 4.5 (derived based on chemistry data in Grasby 1997). The fact that the

average SO4/Cl ratios increased above 4.5 along the river downstream of Calgary’s

WWTPs supports earlier findings about the importance of contribution from prairie SO4 sources. At Carseland (302 km), the annual SO4 loads increased by more than 50kt (Figure 6.3a) with respect to levels upstream of Calgary’s WWTPs (212 km) due to admixture of the wastewater effluents (+23kt) and the tributaries inputs (Elbow + Highwood = +41 kt) (Figure 6.4; Table 6.1).

200 WWTP Bassano Dam RL BC 160 CL (kt) (kt) 4

120 CC

CM 40 Annual Mass Loads of SO

LL 0 0 100 200 300 400 500 600

Distance (km)

6 SD RL BC CN /Cl 4 CL 4.5 SO 4

FC (Plume) 2

WWTP 0 200 300 400 500 600 Distance (km)

Figure 6.3 a) The total annual mass loads of SO4 along the Bow River from Lake Louise (0 km) to Ronalane (571 km) and b) the SO4/Cl mole equivalent ratios downstream of Calgary’s WWTPs.

Figure 6.3b shows that the average SO4/Cl ratios continued to increase from 5.1 at Carseland (302 km) to as high as 6.5-6.7 downstream of Scandia (513 km). The mass

loads of SO4 between Carseland (302 km) and Bow City (482) appeared to be constant in

Figure 6.3a. This could however be an over simplification because SO4 concentrations at Bow City (482 km) were not only highly variable but much of the winter baseflows had to be extrapolated based on historical values. These factors made accurate mass load estimations difficult at this site. Given the computational uncertainties, Figure 6.3a

should not be used to ascertain that the SO4 mass load in the Bow River from Carseland

(302 km) to Bow City (482 km) was constant. Continuously increasing SO4/Cl ratios

from Carseland to Ronalane (302-571 km) suggest that additional SO4 inputs from the prairie reaches of the BRID and EID were significant. Mass balance calculations in

Figure 6.4 and Table 6.1 suggest that the prairies SO4 sources may contribute up to 24%

of the total annual SO4 load at Ronalane (571 km).

Sulphate exported by the Bow River near its confluence with the Oldman River totalled

about 173kt/yr. Although the SO4 loads were evidently increasing downstream of Calgary, the majority of the contribution still originates from the upstream watersheds 2 above Calgary. With a drainage area of 7714 km , SO4 flux from the headwater area to

Calgary was 138±6 kg/ha/yr. In contrast, the SO4 flux output from the prairies between Calgary and the mouth (17535km2) decreased to 37±9 kg/ha/yr. Mass balance calculations summarized in Figure 6.4 and Table 6.1 showed that 66% of the annual total

173 kt of SO4 exported to the South Saskatchewan River originated from the Rocky Mountains, which included contributions from the Elbow and Highwood Rivers. The

prairie sources accounted for 24% of the total SO4 load exported whereas Calgary’s WWTPs contributed 10% (Figure 6.4; Table 6.1). It is clear from Figure 6.4 and Table

6.1 that annual mass loads of SO4 would have increased at Bow City by 30 kt had the -28 kt diversion at the Bassano Dam not been present. The mass load increase observed

between Calgary upstream of WWTPs and Carseland (Figure 6.3a) consisted of SO4 sources from the Elbow River (11 kt), Calgary’s WWTPs (21 kt) and the Highwood River (26 kt) (Figure 6.4; Table 6.1). The wastewater effluents from Calgary accounted

for about 36% of the 57 kt increase whereas the two Rocky Mountain tributaries accounted for the majority (64%) of the increase.

LL 4.4

WID HW R. EID CM -3 28 -28 44

CC Calgary CL Bassano BC RL 105 107 157 Dam 160 173

Elbow R. WWTPs BRID 13 23 -13

Table 6.1 Estimated SO4 mass loads and unknown sources and sinks of SO4 along the Bow River. Percentage contributions from the Rocky Mountain headwaters, Calgary’s WWTPs and the prairie reaches were also calculated. Unknown Sources Estimated Estimated /Sinks Estimated Estimated Estimated SO4 Sources between Headwater WWTPs Prairie Stations Dist. Loads /Sinks Stations Input Input Input (km) (kt) (kt) (kt) (%) (%) (%) LL 0 4.4 100 0 0 CM 99 43.7 39.3 100 0 0 CC 179 104.9 61.2 100 0 0 BN 212 107.0 2.1 100 0 0 Elbow R. ~229 12.6 WID ~229 -2.9 WWTP 230 23.1 HW R. 272 27.6 BRID ~301 -12.6 CL 302 157.3 2.4 85 14 1 EID 425 -27.6 BC 482 159.6 30.0 71 11 17 RL 571 173.5 13.9 66 11 24

6.3 The Isotopic Composition of SO4

6.3.1 SO4 in the Environment 34 18 The typical δ SSO4 and δ OSO4 values of SO4 sources in the environment are shown in

Figure 6.5. Sources of SO4 in the BRB include primarily dissolution of evaporite and 34 oxidation of reduced S. Evaporite SO4 is usually characterized by δ S values greater 18 than +8‰ and δ OSO4 values above +5‰ (Krouse and Mayer 2000). SO4 derived from oxidation of reduced S in contrast, is typically characterized by δ34S values of less than 18 +8‰ and δ OSO4 values of less than +4‰ (Krouse and Mayer 2000). Some data suggest 34 that SO4 in the tills of the Bow River Basin is characterized by δ S values in the range of -8 to -12‰ (Hendry et al. 1986; Fennell and Bentley 1998). Sulphate in soils has isotopic compositions between those of atmospheric deposition and SO4 from oxidation of reduced S (e.g. pyrite and organic S), and the typical values vary between -2 and +10‰ 34 18 for δ S and between 0 and +5‰ for δ OSO4 (Figure 6.5). Except for headwater SO4, riverine and tributary SO4 of the BRB fall within the typical isotopic range of soil SO4 and oxidized S (Figure 6.5).

25 Bow River 0 km 99-212 km 20 302-571 km

Highwood R. 15 Prairie Tributaries Atmospheric Evaporites Deposition 10

(‰) 5

SO4 Soil O

18 0 δ Oxidation of -5 Reduced S

-10

-15 -30 -20 -10 0 10 20 30

34 δ S (‰) SO4

18 34 Figure 6.5 δ OSO4 versus δ SSO4 values for various SO4 sources in the environment (after Krouse and Mayer 2000) and data points in the box are from water samples in the Bow River and it tributaries.

6.3.2 Calgary’s Wastewater SO4

Mass balance calculation (Figure 6.4; Table 6.1) showed that Calgary’s wastewater SO4

accounted for about 10% of the total annual SO4 load at the mouth of the Bow River. 34 The isotopic compositions of wastewater SO4 shown in Table 6.2 reveal that δ S and 18 34 δ OSO4 values were somewhat variable between -1.7 and +5.4 ‰ for δ SSO4 and 18 between -3.9 and +1.2 ‰ for δ OSO4 (Table 6.2). The highest isotopic values in the 34 18 wastewater plume (+8.5‰ for δ S and +1.3 for δ OSO4) and in the effluents (~ +5‰ for 34 18 δ S and ~ +1‰ for δ OSO4) were observed during the spring baseflow month of April 2008 (Table 6.2). In contrast, the lowest isotopic values occurred during the peakflow 34 18 periods in June and July. Evidently, the δ S and δ OSO4 values in the wastewater effluents as well as within the plume decreased as the river transitioned from baseflow to

peakflow. The variable isotopic values in wastewater SO4 reflect that the effluents

contain multiple anthropogenic and natural SO4 sources with complex isotopic signatures.

Table 6.2 Isotopic compositions of SO4 of the treated wastewater effluents from Calgary’s two WWTPs and wastewater plume in the Bow River.

34 18 WWTPs Date δ SSO4 (‰) δ OSO4 (‰) TPBB (230 km) 04/04/2008 4.7 0.6 10/05/2008 2.7 -1.4 22/07/2008 -0.5 -2.2 TPFC (245 km) 04/04/2008 5.4 1.2 10/05/2008 1.5 -1.8 22/07/2008 -1.7 -3.9 FC (248 km) 6/20/2007 4.2 -0.8 7/17/2007 6.4 -1.5 8/30/2007 6.1 -0.7 9/29/2007 9.3 -6.4 10/25/2007 6.7 0.2 11/29/2007 8.2 -0.4 4/2/2008 8.5 1.3 5/8/2008 6.8 -0.7 6/12/2008 -0.1 -0.5 7/22/2008 6.6 -1.8

6.3.3 SO4 in Tributaries 34 Samples obtained from the Highwood River showed wide δ SSO4 variations between -8.6 18 and +1.6 ‰ whereas δ OSO4 values varied little within -1.3 to +1.3‰ (Figure 6.6). Of 34 the nine small prairie tributaries, five (solid triangles) showed δ SSO4 variations rarely 34 exceeding 2.5‰ as opposed to the rest of the tributaries with highly scattered δ SSO4 34 values (open symbols) with δ SSO4 varying between -8 and +7‰ (Figure 6.6). The

isotopic values of the tributary SO4 were variable ranging from as high as +7.5‰ for 34 18 34 18 δ SSO4 and +1.5‰ for δ OSO4 to as low as -13‰ for δ SSO4 and -8.5‰ for δ OSO4 (Figure 6.6). Some tributaries towards the west close to the Blackfoot Plain near Bassano 34 18 (CF Ck. and E1716) had lower δ SSO4 and δ OSO4 values (green) than those (E1413 and 18 B1212; orange and red) located towards the east (Figure 6.6). B1516 had higher δ OSO4 values above +1‰ than most of the other tributaries and low δ34S values around -3‰ (Figure 6.6). Near Ronalane, tributaries E1413 and B1212 were characterized by higher 34 18 δ SSO4 and δ OSO4 values (orange-red solid triangles) than other tributaries (Figure 6.6).

Many of those tributaries (E1717, E1616, E1415 and B1416) showing highly variable

and scattered isotopic values of SO4 were located in EID near Bow City south of Brooks. Many irrigation fields near Brooks, a major municipality on the prairies, are cattle grazing fields, and many are used for feedlot operations. As it is also a common practice to spread manure and sewage sludge on prairie fields, nearby surface waters and regional groundwaters may potentially be affected by SO4 in these sources. The isotopic

similarity between SO4 in the tributary waters and SO4 in Calgary’s wastewater effluents suggests that some stream waters in the irrigation districts may be contaminated by manure and wastewater derived SO4 with variable isotopic signatures. This scenario is highly probable given communities within EID like Tilley, Rosemary, County of Newell utilize EID canals and reservoirs as sources of their water supply as well as means of wastewater disposal to the Bow River (Bow River Basin Council 2005).

5.0

2.5

Highwood River 0.0 CF Ck. E1717

(‰) -2.5 E1716 E1616 SO4

O B1516 18

δ B1416 -5.0 E1415 E1413 B1212 -7.5

-10.0 -15 -10 -5 0 5 10

34 δ S (‰) SO4

18 34 Figure 6.6 Dual isotope diagram showing the δ OSO4 and δ SSO4 values for samples from the Highwood River and the prairie tributaries.

6.3.4 SO4 in the Bow River 34 The δ SSO4 values of the Bow River at Lake Louise were high in the range of +18.0 to 18 +19.7‰ and the δ OSO4 values were low between -7.7 and -6.0 ‰ (Figure 6.7). 18 Riverine SO4 at Canmore (99 km), Cochrane (279 km) and Calgary (212 km) had δ OSO4 values between -2.5 and +2.5‰, higher than those at Lake Louise (0 km) (Figure 6.7). 34 The δ SSO4 values at Canmore (99 km) varied by less than 2.5‰ ranging between +12.1 18 and +14.6‰ whereas the δ OSO4 values fluctuated between -1.2 and +2.7‰ (Figure 6.7). A similar pattern of isotopic variation was also observed at Cochrane (179 km) and 34 18 Calgary (212 km) although the overall δ S and δ OSO4 values decreased by less than 18 34 1‰ for δ OSO4 and around 2‰ for δ SSO4 (blue squares) (Figure 6.7).

Downstream of Calgary, the isotopic compositions of SO4 ranged between -1.2‰ and 34 18 34 +8.8‰ for δ SSO4 and between -3.0 and +1.2‰ for δ OSO4 (Figure 6.7). The δ SSO4 18 values decreased significantly, by more than 10‰, while the δ OSO4 values decreased

less, by about 4.3‰ (Figure 6.7). The isotopic values of SO4 at Carseland (302 km) and thereafter were similar to those of the wastewater plume in the Bow River at 248 km 34 (green triangles), ranging between 0 and +10‰ for δ SSO4, and between -2.5 and +2.5‰ 18 for δ OSO4 (Figure 6.7). Given that the isotopic compositions of SO4 from the WWTPs in Calgary (Figure 6.7; Table 6.2) overlapped with those of the prairie tributaries (Figure 34 18 6.6), δ SSO4 and δ OSO4 values cannot be used to distinguish wastewater SO4 from those derived from the prairie sources using isotopic techniques alone.

5.0

2.5

Bow River a/b WWTP 0 km 99 km 179 km 0.0 212 km

Wastewater Plume 248 km

Bow River b/w WWTP (‰) -2.5 302 km 378 km SO4 482 km O 513 km

18 571 km δ -5.0 Wastewater Effluent TPBB TPFC

-7.5

-10.0 -5 0 5 10 15 20 25

34 δ S (‰) SO4

18 34 Figure 6.7 Plot showing δ OSO4 values versus δ SSO4 values of the Bow River water from Lake Louise (0 km) to Ronalane (571 km) and the wastewaters at Calgary.

34 18 Separating the peakflow from the non-peakflow δ SSO4 and δ OSO4 values reveals that

the isotopic composition of SO4 throughout the Bow River during peakflow (June and July) were typically lower than those during non-peakflow periods (Aug-April baseflow

and early snowmelt in May) (Figure 6.8). This suggests an increased SO4 load to the Bow River from runoff through the soil zone where oxidation of organic S in the presense of infiltrating groundwater occurs.

5.0 August-May June - July 2.5

0.0

(‰) (‰) -2.5 SO4 O 18 δ -5.0

-7.5

-10.0 -5 0 5 10 15 20 25 34 δ S (‰) SO4

18 34 Figure 6.8 Plot showing δ OSO4 values against δ SSO4 values of the Bow River water during peakflow and non-peakflow periods.

Seasonal variations of SO4 isotopic values along the river are shown in Figure 6.9. In the 34 summer, the δ SSO4 values gradually decreased from around +18‰ at Lake Louise (0 18 km) to around +5‰ at Ronalane (571 km) (Figure 6.9a). The δ OSO4 values increased markedly from around -7‰ at Lake Louise (0 km) to around -1‰ at Canmore (99 km) and remained essentially constant in the river thereafter (Figure 6.9a). In the fall, the 34 δ SSO4 values decreased in a step-like fashion with the most noticeable decreases occurring between Lake Louise (0 km) and Canmore (99 km) and between Calgary (212 34 18 km) and Carseland (302 km) (Figure 6.9b). Both δ SSO4 and δ OSO4 values remained constant throughout the prairies downstream of Carseland (302 km) in the fall (Figure 6.9b).

a Summer: June – August

25 Calgary 4

20 2 Aug.

15 0 (‰) (‰) 10 -2 SO4 SO4 S O 34 18 δ 5 -4 δ

Jun. 0 -6

-5 -8 0 100 200 300 400 500 600 Distance (km )

b Fall: September – November

25 Calgary 4

20 2

15 0 (‰) (‰) (‰) 10 -2 SO4 SO4 S O 34 18 δ 5 -4 δ

0 -6

-5 -8 0 100 200 300 400 500 600 Distance (km )

c Spring: April – June

25 Calgary 4

20 2

15 0 (‰) (‰) (‰) 10 -2 SO4 SO4 S O 34 18 δ 5 Apr -4 δ

May 0 Jun -6

-5 -8 0 100 200 300 400 500 600 Distance (km )

The ranges of isotopic values for riverine SO4 in early spring (Apr08) were similar to those in fall but by mid May in the early snowmelt period, the amount of scattering and 34 variation increased. The δ SSO4 values decreased from +19‰ to 0‰ between Lake Louise (0 km) and Ronalane (571 km) (Figure 6.9a) as opposed to from +18‰ to +5‰ 18 (Figure 6.9a-b). Variations in δ OSO4 values however, were between +2 and -3‰, not significantly different among different seasons (Figure 6.9). The spatial trend in late spring (Jun08) was not significantly different from that in May except for the lower 34 18 δ SSO4 and δ OSO4 values (Figure 6.9c). An inverse relationship was observed between the isotopic compositions of SO4 (Figure 6.9) and the SO4 concentrations (Figure 6.2a) and the relationship was particularly apparent during the snowmelt-rainfall period in May 34 and June. Similarly the average δ SSO4 values and the annual SO4 loads in the river were 34 inversely related (Figure 6.10). Increases in SO4 loads coupled with decreases in δ S values of SO4 suggest that there were variable SO4 sources with different isotopic

compositions of SO4 mixing along the length of the river. The extent of contributions

from the variable sources of SO4 varied between peakflow (May – July) and baseflow (August – April) seasons.

Lake Louise 20 0

15 99

(‰) (‰) 179

SO4 212

S 10 34 δ

Ronalane 5 302-571 km

0 0 50 100 150 200

Annual Mass Loads of SO (kt) 4 34 Figure 6.10 Plot showing the SO4 flux-weighted average δ SSO4 values versus the annual mass loads of SO4 in the Bow River from Lake Louise (0 km) to Ronalane (571 km).

18 6.4 Relationship between δ O Values of SO4 and H2O

Insight into the sources of SO4 in the Bow River can be acquired through evaluating the

oxygen isotope ratios of SO4 and H2O because water has been known to influence the 18 δ O values of SO4 produced in oxidation experiments (Holt et al. 1981; Taylor et al. 1984; Fritz et al. 1989; Van Stempvoort and Krouse 1994; Balci et al. 2007). Early

experiments of air oxidation of SO2 showed that 60% of oxygen in SO4 was derived from

H2O under conditions facilitating rapid isotope equilibrium (Holt et al. 1981). In 3+ contrast, SO4 produced via Fe catalyzed air oxidation with excess water had higher

percentage (70%) of oxygen incorporation into SO4 from H2O (Holt et al. 1981). The upper boundary of the sulfide oxidation field shown in Figure 6.11 was generated based on results published by Taylor et al. (1984) and corresponds to 63‰ of oxygen

incorporation into SO4 from H2O. The lower boundary in Figure 6.11 represents the

maximum 100% contribution of oxygen in SO4 from H2O, assuming no isotopic fractionation during oxygen incorporation from H2O into SO4. Recent pyrite oxidation experiments conducted by Balci et al. (2007) under both biotic and abiotic conditions demonstrated that SO4-oxygen was mainly derived from H2O and the revised estimates

suggest that as much as between 85 and 92% of SO4-oxygen came from H2O.

Based on a pyrite oxidation pathway proposed by Schipper et al. (1996), experimental estimates were further tested and verified stoichiometrically by Balci et al. (2007). Stoichiometric determination suggested five intermediate steps leading up to the following net reaction:

3+ 3+ 3+ 2+ + 2 2FeS2 + 12Fe(H2O)6 + 19H2O + 2Fe + ½O2 →14Fe(H2O)6 + 2Fe + 14H + 2SO4

+ 0.25S8 (Schipper et al. 1996)

resulting in 87.5% of oxygen in SO4 been incorporated from H2O and 12.5% from O2 18 18 (Balci et al. 2007). Consequently, the 87% line showing the δ OSO4-δ OH2O relationship

derived from 87% of H2O-oxygen incorporation in SO4 in Figure 6.11 provides the best

representation for the initial isotopic compositions of oxygen in SO4 and H2O when

reduced S is oxidized to SO4.

Except for B1516 and some of the EID tributaries (open green triangles), most prairie 18 18 tributaries had δ OSO4 and δ OH2O values near the sulfide oxidation field at the 63% line 18 (Figure 6.11). Some tributary waters (open green triangles) displayed δ OSO4 and 18 δ OH2O values similar to those of Bow River SO4 at Ronalane (571 km) (black solid 18 18 squares). The fact that the δ OSO4 and δ OH2O values of the tributaries fell within the 34 range typical for sulfide oxidation is consistent with their corresponding δ SSO4 values ranging between -15 and +10‰ (Figure 6.6), also within the isotopic range produced by sulfide oxidation (Figure 6.5). Hence, the majority of the isotope data suggest that SO4 in the prairie tributaries was mostly derived from oxidation of sulphide minerals and other forms of reduced S such as organic S in the soils.

Except for river water at Lake Louise (0 km), the Bow River water from Canmore to 18 18 Ronalane (99-571 km) had δ OSO4 and δ OH2O values outside the sulfide oxidation field 18 above the 63% line in Figure 6.11. However, the observed δ OSO4 values between -3

and +3‰ were lower than those typical for SO4 from evaporite dissolution having 18 34 δ OSO4 values between +5 and +20% (Figure 6.5). This is in contrast to the δ SSO4 values between +10 and +20‰ (Figure 6.7), which is consistent with the typical isotopic range for SO4 derived from dissolution of evaporite (Figure 6.5). Atmospheric deposition 18 has δ OSO4 values typically varying between +5 and +15‰ (Figure 6.5) (Krouse and

Mayer 2000) and can not contribute more than 17% of the total annual SO4 flux at

Calgary as calculated based on a SO4 deposition rate of 22.4 kg/ha/yr (Legge 1988;

Grasby 1997). This is an upper estimate calculated under the assumption that SO4 was conservative with a one-year maximum residence time throughout the watersheds above 18 Calgary. Nevertheless, the lower than expected δ OSO4 values indicate that SO4 originating from the Rocky Mountains is likely derived from a mixture of sources including atmospheric deposition, soil-derived SO4, sulfide oxidation, and evaporite dissolution.

100

Bow River 5 0 km 99 km 179-212 km 302-482 km 0 571 km

Prairie Tributaries

(‰) -5 CF Ck.

SO4 E1717

O E1716 18 87% δ -10 E1616 B1516 63% B1416 E1415 -15 Sulfide Oxidation Field E1413 B1212

-20 -35 -30 -25 -20 -15 -10 -5 0 18 δ O (‰) H2O

34 At Lake Louise (0 km), the δ SSO4 values (+16.5 to +19.7‰) were within the isotopic

range typical for SO4 derived from dissolution of evaporites (Figure 6.7), but the negative 18 δ OSO4 values (-5.8 to -7.7‰) within the sulfide oxidation field (Figure 6.11) are not consistent with simple dissolution of primary evaporites. Grasby (1997) attributed the 34 18 cause of the unusual δ SSO4 and δ OSO4 values observed at Lake Louise (0 km) to

repeated redox reactions and suggested that evaporite SO4 was first reduced to sulfide and then re-oxidized in groundwater before reaching streams and rivers. Since the Main Ranges of the Rocky Mountains are dominated by Late Precambrian and Lower Cambrian sedimentary strata deposited in shallow marine environments (Section 2.4;

101

34 Chapter 2), an alternative explanation is proposed here on the basis of variable δ SFeS values between -10 and +20‰ associated with sedimentary pyrite of Neoproterozoic age (Strauss 1993, 1994 and 1997).

For the Main Ranges, oxidation of pyrite having positive δ34S values close to +20‰ 34 18 would produce SO4 with δ S values similar to those of this source, but the δ OSO4 values would be expected be around -15‰ according to the experimentally determined 34 87% line in Figure 6.11. The hypothesis regarding SO4 derived from oxidation of S enriched sulphide minerals in the Late Precambrian and early Cambrian geological formations of the Rocky Mountains, however, should be tested in future studies. In addition, the fact that all the values in Figure 6.11 plotted above the 87% line is a reflection of an open system condition under which pyrite oxidation occurred

concurrently with mixing of SO4 from other sources such as atmospheric inputs and oxidation of other reduced S compounds infiltrating through the soil zone and

groundwaters. To further differentiate between atmospheric and organic sources of SO4 in the Bow River was beyond the scope of this study.

6.5 Mass Balance Calculations

Mass balance calculations for SO4 for each physiographic reach of the Bow River are

summarized in Table 6.3. Sources of SO4 from the Rocky Mountains have uniform and 34 18 relatively constant δ SSO4 and δ OSO4 values. The average isotopic composition of SO4 in the Bow River in Calgary above WWTPs (212 km) was therefore used in the mixing

model in Figure 6.12. Since there are multiple SO4 sources in the Bow River and

wastewater effluents and prairie tributaries have variable isotopic compositions of SO4, isotope balance in a two-end member mixing model is not possible. Instead, the trend δ18O = 0.13 δ34S - 1.15 in Figure 6.12 was used in combination with annual solute load balance to help delineate the isotopic composition of SO4 derived from mixed wastewater and prairie sources.

102

-50 to 0 0 to 99 99 to 179 to 212 231 to ~250 ~250 to 571 km km km 179 km km km 571 km

SO4 (kt) 3.1 31.3 47.7 9.8 18 64 174 % Input 1.8 18.0 27.4 5.6 10.4 36.8 100

34 δ S (‰) 18.5 12.5 11.0 10.4 -1.7 ~ +5.5 -3.8 ~ -0.8 5.0 18 δ O (‰) -6.5 1.1 0.2 0.2 -3.9 ~ +1.2 -2.4 ~ -0.2 -0.5

5.0

2.5 10% Source 1: Wastewater Rocky Mt. Source 2: 212 Prairies 99 0.0 179 302-571 53-63% (‰) -2.5 18 34 δ O = 0.13δ S-1.15 SO4 O 18 δ -5.0

0 km -7.5 63% 53% (-3.9, -1.7) (-0.5, -1.3) -10.0 -15 -10 -5 0 5 10 15 20 25

34 δ S (‰) SO4

103

A 66% (Figure 6.4; Table 6.1) SO4 contribution from mountainous watersheds including those upstream of Calgary and the Highwood River would require the mixed prairie and 34 wastewater SO4 source to have an average isotopic composition of -4.9 for δ SSO4, and 18 -1.9 for δ OSO4 (Figure 6.12). Excluding contributions from the Highwood River, watersheds upstream of Calgary account for 53% (Figure 6.4; Table 6.1; Table 6.3) of the

total SO4 load at Ronalane (571 km) and the average isotopic compositions of the mixed 34 18 prairie and wastewater sources becomes -0.5 for δ SSO4 and -1.3 for δ OSO4 (Figure 18 6.12). Since SO4 in the Highwood River has scattered and seasonally variable δ OSO4 values resembling both the Rocky Mountain source (July-April) and the prairie tributary source (May-July) (Appendix B: J1-10), SO4 loads from the Rocky Mountains may be best represented by a range of values within 53-63% (Figure 6.13). Since Calgary’s

WWTPs contributed ~10% of the total SO4 load in the Bow River (Figure 6.12), mixed prairie and wastewater SO4 sources from the prairies were estimated to account for 27

37% of the riverine SO4 load near the confluence with the South Saskatchewan River.

6.6 Summary Sulphate fluxes in the Bow River increased over an order of magnitude within the 210 km stretch between Lake Louise and Cochrane but subsequently changed little with only small increases on the prairies. Mass balance calculations combining isotopic values and

mass loadings of SO4 showed that the Rocky Mountain headwaters including the Elbow

and the Highwood Rivers contributed approximately 60% of the total SO4 load to the Bow River near its confluence with the Oldman River whereas Calgary’s wastewater effluents only contributed 10%. The remaining 30% is contribution from the prairie reaches. The total SO4 loads leaving the Bow River Basin in a year amount to around 173kt. Contributions from watersheds upstream of Calgary amounted to 138±6 kg/ha/yr whereas the prairie reaches only contributed 37±9 kg/ha/yr.

34 Although the high δ SSO4 values close to +20‰ at Lake Louise indicate that SO4 could be derived from dissolution of evaporites, oxygen isotope ratios of SO4 rather suggest

that riverine SO4 in the Main Ranges of the Rocky Mountains is derived from oxidation

104 of 34S enriched pyrite commonly found in Neoproterozoic and early Cambrian strata

(Strauss 1993, 1994 and 1997). Downstream of Lake Louise, SO4 concentrations 34 increased with decreasing δ SSO4 values from as high as +7‰ upstream of Calgary to as low as -1‰ at Ronalane, showing mixing with SO4 derived from oxidation of reduced S. The isotopic values of the wastewater effluent at Calgary varied somewhat with season 34 18 between -1.7 and +5.5‰ for δ SSO4 and between -3.9 and +1.2‰ for δ OSO4 reflecting

multiple SO4 sources with complex isotopic signatures. The highly scattered and variable 34 18 δ SSO4 and δ OSO4 values also observed in many prairie tributaries, especially those near Brooks, where feedlots and cattle grazing fields are common, suggest potential wastewater or manure contamination of some prairie tributaries.

The trend of increasing SO4 concentrations with flow distance accompanied by 34 decreasing δ SSO4 values suggests a mixture of SO4 sources in the Bow River including

oxidized pyrite and dissolution of CaSO4 in the Rocky Mountains, municipal wastewater effluents, and oxidation of till pyrite on the prairies. Although contributions from

atmospheric SO4 and oxidation of soil organic S were not quantified in this study, the 18 δ OSO4 values suggest that they were also important sources of riverine SO4. Upstream

of Calgary, riverine SO4 originates mainly from evaporite dissolution whereas downstream of the city, oxidation of till pyrite and wastewater derived SO4 from Calgary

and other municipalities on the prairies became major sources of SO4 amounting to about

40% of the total SO4 load in the final 30 km stretch of the river.

105

CHAPTER 7: IDENTIFYING THE SOURCES AND TRACING THE FATE OF NITRATE IN THE BOW RIVER

7.1 Introduction

Excessive NO3 in rivers of populated watersheds worldwide is a growing concern and is now considered together with other reactive forms of N a major pollution problem in many coastal waters (e.g. NRC 2000; Howarth et al. 2002; Rabalais 2002), the ultimate sink of N from the atmosphere and lands. Nitrate concentrations in many river networks have risen rapidly since the mid 20th century (e.g. Howarth et al. 1996; Galloway et al. 2004) and negative environmental consequences are often manifested in eutrophication, hypoxia and loss of biodiversity in rivers, lakes, estuaries, and coastal marine waters (e.g. Rabalais et al. 2001; Paerl et al. 2002). The dramatic human perturbation of the N cycle is predicted to have severe cascading effects on the environment under current management practices (Galloway et al. 2003). Given that rivers are the ultimate linkage between the atmosphere, the land, and the ocean, a basin-wide study of riverine NO3 is

important for understanding the role of NO3 in the global N cycle.

In Alberta, agricultural activities, feedlot operations and urban wastewaters are likely the major sources of anthropogenic nitrogen. Rarely are these sources studied on a basin- wide scale. A few decades ago, the Bow River water was severely degraded by eutrophication causing dense macrophyte growth below the Calgary wastewater outlet (Hamilton 1982; Ongley et al. 1982; Sosiak 2002). In 1979, dense macrophyte growth extended beyond the Bow and the Oldman River confluence (Alberta Environment 1979). Upgrades to Calgary’s wastewater treatment facilities between 1982 and 1990 substantially reduced nutrient loads and improved river water quality downstream of Calgary. A large decline in the aquatic biomass was strongly associated with reduced N loads (Sosiak 2002). Although nutrients in the forms of both N and P compounds can influence macrophyte growth, the Bow River exhibited signs of N limitation suggesting that the availability of N could be a key determinant of the biomass state of the Bow River (Sosiak 2002; Hogberg 2004).

106

Despite substantial nutrient load reduction from the WWTPs in Calgary, remediation efforts have occasionally failed to maintain the Bow River’s water quality at an environmentally desirable state. The quality of the river water below the Carseland weir from 1990 to 2001 had been frequently rated “fair” indicating that the water had occasionally exceeded guideline concentrations (Bow River Basin Council 2005). The most recent rating indicated that the nutrient state of the Bow River had not improved because the same rating was applied to the river at Carseland, Cluny and Ronalane in 2007 and 2008 (Alberta Environment 2010). Macrophyte biomass in the Bow River was found to correlate inversely with flow and positively with N concentrations showing that flow, in addition to nutrient loading, can influence macrophyte biomass (Sosiak 2002). Clearly, biological assimilation of nutrients in the Bow River is not controlled solely by

their availability. As urbanization and population continue to expand in Calgary, NO3 loading in the Bow River could potentially increase in the foreseeable future. Given that managing riverine biomass by flow regulation is impractical, maintaining nutrient loadings to the river at the current state, if not further reducing them, is an inevitable challenge. The fact that low dissolved oxygen levels often occurred in spring and fall downstream of Calgary (Iwanyshyn et al. 2008; Robinson et al. 2009) is further evidence of enhanced diurnal fluctuation triggered by nutrient loadings to the Bow River.

Although highly soluble and non-particle reactive, NO3 is not conservative in natural ecosystems. The fate of nitrate could be affected by transformations during transfer among different sinks and sources (e.g. Stevenson 1972 a, b; Brezonik 1973; Hem 1985). Nitrate in aquatic ecosystems may be produced from nitrification of reduced N species, removed by denitrification and assimilated into the aquatic biomass. Other NO3 removal pathways in aquatic systems such as dissimilatory reduction of nitrate to ammonium (DNRA) and anaerobic ammonium oxidation (anammox) (Burgin and Hamilton 2007) are creating interest among researchers and may one-day offer additional insights into N cycling in riverine systems.

107

Quantifying the variable source contributions to riverine NO3 loads may benefit from 15 18 evaluating the isotopic compositions of NO3 and incorporating δ N and δ O values in

mass-balance computations if different NO3 sources have different isotopic signatures. The accuracy of isotope mass balance calculations had often been hampered by variable isotopic fractionation during N transformation processes and overlapping isotopic values of the multiple nitrate sources (e.g. Gravotta 1997; Kendall et al. 2007). However, it is

generally believed that isotopic compositions of NO3 are sufficient in yielding qualitative information about the dominant processes and sources provided that the isotopic signatures are distinct (Gravotta 1997).

Although the Rocky Mountain watersheds have been regarded as relatively pristine (Bow River Basin Council 2005), wastewater facilities for the small villages and towns at Lake Louise, Banff and Canmore may contribute small but significant amounts of nitrate to the Bow River. Irrigation return flows on the prairie plains may also be an important non- point source of nitrate in the lower reaches of the Bow River. Unlike many highly populated watersheds that have had a long history of urbanization and of accumulation of multiple N source inputs along their river networks, the potential sources of nitrate in the Bow River Basin are geographically separated and not as complex as in many other populated river basins. The relatively few types of nitrate sources and land use activities within the Bow River Basin are advantageous for testing the suitability of using the

isotopic composition of NO3 as a tracer. Concentration and flow data provide information about mass loadings of nitrate in the river (see also Tables 5.1-5.2; Chapter

5). A better understanding of the sources and fate of NO3 in the Bow River may be acquired by the combined use of nitrate concentrations and their isotopic compositions. In this chapter, major ion concentrations and isotopic values are used to identify the major sources of NO3 in the Bow River and to quantify their relative contributions at the final reach of the river.

108

7.2 NO3 Concentrations in the Bow River

Upstream of the WWTPs in Calgary, NO3 concentrations in the Bow River were generally below 0.4 mg/L (Figure 7.1). Downstream of Calgary at Carseland (302 km), the NO3 concentrations of the Bow River increased by over 10 times compared to those upstream of the WWTPs (Figure 7.1). The concentrations of NO3 in the Bow River were variable downstream of Calgary (Figure 7.1). In June and July of 2007, concentrations were <1.7 mg/L but one month later, NO3 concentrations increased to between 1.7 and

4.6 mg/L (Aug-Oct) (Figure 7.1a). By late November 2007, NO3 concentrations in the Bow River were among the highest exceeding 4.6 mg/L (Figure 7.1). A sample from

Ronalane (571 km) showed a NO3 concentration below the detection limit (<0.04 mg/L) in July 2007 during the irrigation period. Similarly again in July 2008, the NO3 concentration decreased to below 1 mg/L at Ronalane (571 km) (Figure 7.1b). Low NO3 concentrations below 1 mg/L were also observed at Cluny (378 km) in the summer (Jun-

Jul 2008) (Figure 7.1b). The occurrences of such low NO3 concentrations downstream of

Calgary is not in accordance with the general overall trend showing NO3 concentrations above 1 mg/L.

In June and July 2007, the Bow River NO3 concentrations between Carseland (302 km) and Ronalane (571 km) remained constant around 1 mg/L, but from August to late October, the concentrations at Ronalane (571 km) were consistently lower than those of upstream sites (CL, CN and BC) (Figure 7.1a). During the ice-covered baseflow period in late fall (Nov07), NO3 concentrations increased successively with flow distance after passing Carseland (302 km) and even exceeded 7 mg/L at Bow City (482 km) (Figure

7.1). The trend of increasing NO3 concentrations with flow distance downstream of Carseland (302 km) was observed as early as late October (Figure 7.1a). This is contrasted by NO3 concentrations decreases along flow distance past Carseland (302 km) in September 2007 and Cluny (378 km) in August 2007 (Figure 7.1a). These spatial decreases in August and September resulted in minimum NO3 concentrations of about 1 mg/L at Ronalane (571 km), a level similar to that in June and July.

109

8 Jun07 WWTP Bassano Dam Jul07 7 Aug07 BC Sep07 RL 6 Oct07 CN Nov07 5 CL

4 (mg/L) (mg/L) 3 3 NO

1 LL CM CC

0 0 100 200 300 400 500 600 Distance (km)

8 Nov07 WWTP Bassano Dam Apr08 7 May08 BC Jun08 RL 6 Jul08 CN

5 CL

4 (mg/L) 3 3 NO

1 CM CC LL

0 0 100 200 300 400 500 600 Distance (km)

Figure 7.1 NO3 concentrations of Bow River waters sampled between the headwaters at Lake Louise (0 km) and near the mouth at Ronalane (571 km) from a) early peak flow recession (Jun07) to the ice-covered baseflow conditions (Nov07), and b) from ice- covered baseflow (Nov07) to summer peakflows (Jul08).

110

The Bow River was ice-covered by late November 2007. The melting of the river ice started in March and by the first week of April in 2008, the Bow River except at Lake

Louise, was completely ice free. Downstream of Calgary, baseflow NO3 concentrations observed in November 2007 differed from those in April 2008. Concentrations in November 2007 increased between Bow City (482 km) and Ronalane (571 km) but decreased in April 2008 (Figure 7.1b). The same pattern continued from April into May as spring baseflow was transitioning into summer peak flow. The spatial patterns varied little between April and May of 2008 but the concentrations were overall lower in May because of dilution by snowmelt and rain runoffs (Figure 7.1b).

The contrasting spatial trends between the ice-covered (Nov07) and ice-free (Apr08)

months in Figure 7.1b reveal that the Bow River NO3 concentrations downstream of Calgary were not constant throughout baseflow periods. The differences may be partly explained by changing biological activity within the riverine ecosystem. The increasing

NO3 concentrations with flow distance in late fall (Nov 2007) may be caused by reduced biological demand during the river’s ice-covered dormant periods. Furthermore, formation of river ice lowers flows and reduces the river’s dilution capacity. Most

importantly, the fact that NO3 concentrations increased from mid (Oct07) to late fall

(Nov07) (Figure 7.1) throughout the prairie reaches may suggest that NO3-rich groundwater discharge to the Bow River during periods of increasing baseflow from the surrounding irrigation fields and tributaries is significant.

Although the macrophyte growing season in the Bow River is typically from May to September (Sosiak 2002), the similarity between the April 2008 and the May 2008 trends in Figure 7.1b may suggest that biological activity in the river could have increased as soon as the river became ice-free by early April in 2008. This is consistent with the observed diurnal cycles in dissolved oxygen in early spring showing evidence of active photosynthesis and respiration processes in the Bow River (Iwanyshyn et al. 2008). After the 2005 flood, strong correlation between periphyton (chlorophyll-a) concentrations and dissolved oxygen in the Bow River were observed (Robinson et al. 2009) showing that

111

the microscopic plants were unaffected by the flood whereas a substantial amount of macrophyte was removed. Given low flows were correlated with enhanced macrophyte growth in the Bow River (Chambers et al. 1991; Sosiak 2002; Hogberg 2004), decreasing

NO3 concentrations with flow distance downstream of Calgary in September 2007 (Figure 7.1a), April 2008 and May 2008 (Figure 7.b) may be caused by biological

assimilation of NO3 related to macrophyte and periphyton growth in the river.

7.3 The Bow River NO3 – Flow Relationships 7.3.1 Upstream of Calgary

During non-peak flow periods, NO3 concentrations in the Bow River upstream of Calgary were highly scattered (below 0.5 mg/L) with respect to flows (Figure 7.2). During the

peakflow period in June and the early flow recession in July, NO3 concentrations increased linearly with cumulatively increasing downstream flows from Lake Louise (0 km) to Cochrane (179 km) (Figure 7.2). The increase in NO3 concentrations with flows during the runoff period in the forested catchments is likely related to flushing of soil

NO3 (see also Section 7.7.3). The linear relationships between flow and NO3 concentrations for June 2007 and 2008 are represented by equations: y = 0.0008x + 0.1737 (r2 = 0.9864) and y = 0.001x + 0.4246 (r2 = 0.8095) respectively. The intercept difference of 0.25±0.06 mg/L indicates that the headwater NO3 concentrations during the peakflow period in 2007 were uniformly 0.25±0.06 mg/L lower than those in 2008.

The cause of the offset between the two linear trends in Figure 7.2 was likely related to differences in precipitation distribution and peakflow hydrology in 2007 and 2008. As already discussed in Chapter 4 (Section 4.2), the Rocky Mountains received more precipitation in 2007 than in 2008. Correspondingly, the Bow River headwater flow in spring during the snowmelt period was also higher in 2007 than in 2008. As an example, the total headwater discharge estimated at Canmore (99 km) in 2007 was >200GL higher (1.2 times increase) than that in 2008 (Chapter 5 - Table 5.1). Therefore, lower peakflow

NO3 concentrations in 2007 than in 2008 can be explained by increased dilution from plentiful snowmelt and rainfall runoff to the Bow River in 2007.

112

A positive slope for the NO3 concentration-flow relationship in Figure 7.2 would not be

possible had the NO3 mass loading or flux from the Main Ranges to the Foothills remained constant. Although the increases seemed small within 0.3 mg/L, it is still approximately 10 times higher than the measurement detection limit of 0.04 mg/L. A

positive trend means that NO3 loadings to the Bow River increased with increasing drainage contribution along the river from high alpine ranges to subalpine-montane river valleys. Note that differentiating the linear relationships results in dC/dQ = d(M/V)/d(V/t) = dM/dt = constant, where C, Q, M, V, t represents concentrations, flows, mass, volume and time respectively. The similarity between the two slopes means there

is no difference between NO3 fluxes (dM/dt) of 2007 and 2008. In other words, the

amount of NO3 flushed from the forest soil to the river was constant and that the availability of soil NO3 is limited irrespective of different hydrological conditions.

1.0 non-peakflow periods

2007 2008 0.8 peakflow (June) peakflow (July) 2008 y = 0.001 X + 0.4246 (n=4, r2=0.8095) 0.6

(mg/L) (mg/L) 179 km 3 2007 0.4 212 NO 99

0 km 0.2 y = 0.0008 X + 0.1737 (n=4, r2=0.9864)

0.0 0 50 100 150 200 250 300 350 Flow (m3/s)

113

The NO3 concentrations of the Rocky Mountain reaches of the Bow River responded to variations in the seasonal hydrology. In the high elevation catchments where soil development is relatively poor and slopes are steep in comparison to the lower elevation

subalpine-montane river valleys, the NO3 concentration-flow relationships during both

rising flow and the receding flow periods were similar as fluctuation in NO3 concentrations occurred with low flows ranging between 5 and 10 m3/s (Figures 7.3 a and b). This reflects the sporadic headwater hydrology related to thin regolith and poor soil development which causes sharp transitions from runoff to baseflow or vice versa (Domenico and Schwartz 1990). The Bow River at Lake Louise (0 km) shows a headwater condition free of impacts from wastewater effluents and maximum flow here occurred a month later in July relative to the rest of the watershed as a result of continued snowmelt and interflow contributions from the high elevation Rocky Mountains. At

Lake Louise (0 km), the occurrence of the highest NO3 concentration of 0.46 mg/L coincided with the timing of maximum flow in July 2008 (Figure 7.3a).

At Cochrane (179 km) where the Bow River transitions from the Rocky Mountain

Foothills to the Plains, the NO3 concentration-flow relationships remained similar to those in headwaters in that the highest concentration of 0.65 mg/L were reached under maximum flow in June 2008 (Figure 7.3c). Throughout the flow recession in 2007, the

NO3 concentration-flow relationships at Lake Louise (0 km) and Cochrane (179 km)

were different but the overall trends of decreased NO3 concentrations with receding flows

were the same (Figure 7.3 b and d). At Cochrane (179 km), the greatest NO3 concentration decline occurred early during flow recession whereas at Lake Louise (0 km), it occurred towards the end of the recession in Sept 2007 (Figure 7.3b and d).

Nevertheless, at both sites, the timing when the highest NO3 concentrations occurred corresponded to when flows approached the maximum. These relationships reflect the

timing of and the different hydrograph responses to soil NO3 flush from the mountainous

reaches of the Bow River. Riverine NO3 occurrences in the Rocky Mountains could also be related to increased wastewater discharges at Lake Louise, Banff and Canmore in the summer from increased tourist visits. Given the similarity in the NO3 concentration-flow

114

relationships between Lake Louise (wastewater free) and Cochrane, it is likely that hydrograph response to the onset of runoff during the snowmelt and rainfall season is still

a primary control of NO3 concentrations in these upper reaches of the Bow River.

Lake Louise (0 km) Cochrane (179 km) a c

0.5 0.7 Jul08 Jun08

Jun08 0.6

0.4

0.5

(-x/8.2485) 0.3 y = 0.481 - 0.5321e 0.4 (mg/L) (mg/L) (mg/L)

3 (-x/222.8596) 3 y = 0.9601 - 1.0374 e NO NO 0.3

Rising Flow 0.2 0.2 May08 May08 Apr08 0.1 0.1 0 5 10 15 20 25 30 0 50 100 150 200 250 300 3 Flow (m3/s) Flow (m /s)

b d

0.20 0.44

Jul07 Jun07 0.18 0.40

0.16 0.36 y = 0.1791 - 0.1999 e(-x/5.8984) Aug07 y = 0.2732 + 0.0044 e (x/83.7931) (mg/L) (mg/L)

0.14 3 (mg/L) (mg/L)

3 0.32

NO Jul07 NO

0.12 0.28 Aug07 Sept07 Receding Flow

0.10 Sept07 0.24 50 100 150 200 250 300 0 10 20 30 40 50 Flow (m3/s) Flow (m3/s)

Figure 7.3 The Bow River NO3 concentration-flow relationships at Lake Louise (0 km) and Cochrane (179 km) during rising flow periods (a and c) and similarly during receding flow periods (b and d).

7.3.2 Downstream of Calgary In contrast to the Rocky Mountain reaches, the Bow River at Carseland (302 km)

displayed decreasing NO3 concentrations with increasing flows with a fitted equation: y=54.4e(-x/23.4) + 1.1 (r2 = 0.89) showing the effect of dilution (Figure 7.4a). For comparison, samples from Cluny were also plotted in Figure 7.4a (assuming flows were constant within 302-378 km). Downstream of the Bassano Dam (422 km), the inverse

115

NO3 concentration-flow relationship was affected by the cluster of low NO3 concentrations (open circles) from samples taken during irrigation seasons (Figure 7.4b).

Variable, but low, NO3 concentrations seemingly independent of flow occurred within the range of 15-125 m3/s from May to early October (Figure 7.4b). The cluster of low

NO3 concentrations during irrigation periods could potentially be caused by dilution, denitrification and/or biological assimilation, which will be discussed in Sections 7.6-7.7.

7 302 km at Carseland 378% (3,@LG) km at Cluny 6

4 (mg/L) (mg/L)

3 3 (-x/23.4) 2 NO y = 1.1 + 54.4e (r =0.885) 2

0 0 100 200 300 400 500 Flow (m3/s)

8 482 km at Bow City Irrigation Period 7 non Irrigation Period Peak Flow Period 6 571 km at Ronalane Irrigation Period 5 non Irrigation Period Peak Flow Period 4 (mg/L) 3 3 NO y = 1.55 + 43.2e(-x/23.14) 2

0 0 100 200 300 400 500 600 Flow (m3/s)

Figure 7.4 Inverse relationships between NO3 concentrations and flows at a) Carseland (302 km) and Cluny (378 km) and b) below the Bassano Dam at Bow City (482 km) and Ronalane (571 km).

116

Comparisons between the NO3 concentration-flow relationships of the Bow River in the Rocky Mountains and on the prairies show contrasting trends. In the Rocky Mountains,

NO3 concentration increased with flow during the summer runoff season in June and

July. On the prairies, NO3 concentrations decreased with flow between Calgary and the

Bassano Dam. The highest NO3 concentration in the Rocky Mountains was <0.7 mg/L

while the lowest NO3 concentrations downstream of Calgary was rarely below 1 mg/L. If instream NO3 removal processes played a role upstream of the Bassano Dam, the overall

effect was apparently not sufficient to alter the inverse NO3-flow relationship shown in

Figure 7.4a. Dilution by increased flows was the primary factor controlling the NO3 concentrations within the reach of the Bow River between Calgary and the Bassano Dam.

Downstream of the Bassano Dam, the cluster of low NO3 concentrations plotting under

the NO3-flow relationship in Figure 7.4b suggest instream NO3 removal during irrigation periods throughout the growing season.

7.4 N from Calgary’s Wastewater Treatment Plants

The main forms of inorganic N compounds in Calgary’s wastewater effluents are NH4 and NO3. At Bonnybrook Wastewater Treatment Plant (TPBB), most of the NH4 from raw sewage is first oxidized (nitrification) to NO3 in an aerobic reactor with nitrifying

bacteria. The generated NO3 is then transferred to an anoxic bioreactor with denitrifying

bacteria for reduction into N2 (g) (denitrification) (City of Calgary 2008). Since this N

removal technique is not 100% efficient, wastewater NO3 is still discharged to the Bow River. Since the Fish Creek Wastewater Treatment Plant (TPFC) does not have

biological N removal reactors, it discharges N compounds mainly in the form of NH4.

NO3 concentrations in the treated wastewater effluent of TPBB were typically in the

range of 48-65 mg/L whereas NH4 concentrations ranged between 0.2 to 0.4 mg/L

(Appendix B-III: T1-3). At TPFC, effluent NH4 concentrations were constant around 30

mg/L with minimal NO3 <0.4 mg/L (Appendix B-III: U1-3). The amount of wastewater N discharged to the Bow River is affected by both concentrations and effluent flows at

the outlet. The NO3 and NH4 flux variations at TPBB were greater than those at TPFC

117

(Figure 7.5). The NH4 and NO3 fluxes from TPFC show small variations between 0.4 and 0.6 kt/month, and 0.001 and 0.005 kt/month respectively (Figure 7.5b). In contrast,

NO3 fluxes discharged by TPBB were more variable ranging between 0.6 and 1.0

kt/month (Figure 7.5a). NO3 discharges to the Bow River were greatest in May, June and

July with TPBB being the main contributor (Figure 7.5a). The NH4 fluxes (2 ton/month) at TPBB were typically over 10 times lower than those at TPFC but increased moderately throughout February, March and April when seasonal discharge concentration criteria are

relaxed. The highest NH4 flux at TPBB was similar to the lowest NH4 flux of 0.04 kt/month at TPFC (Figure 7.5).

a TPBB b TPFC

1.0 0.10 1.0 0.10

0.8 0.08 0.8 0.08

0.6 0.06 0.6 0.06

0.4 0.04 0.4 0.04 Fluxes (kt/month) (kt/month) Fluxes Fluxes (kt/month) (kt/month) Fluxes Fluxes (kt/month) (kt/month) Fluxes Fluxes (kt/month) 4 4 3 3 NH NO NO NH 0.2 0.02 0.2 0.02

0.0 0.00 0.0 0.00

e r r e r r ch n e e ch n e e ne er r u une b rch u J mb mb arch J Ju m a J mb Ma te M Mar M te p ce p e e e S D September Septemb Dece S Months 2007-2008 Months 2007-2008

7.5 NO3 in the Prairie Tributaries

NO3 concentrations in the prairie tributaries were variable and usually low. High NO3 concentrations >1 mg/L only appeared occasionally in some tributary waters, and the timing and the duration when this occurred was variable among the individual tributaries.

Elevated NO3 concentrations in Crowfoot Creek, E1717 and E1716 reached as high as between 1.0 and 7.0 mg/L (Figure 7.6a) whereas in the 12 Mile Creek (E1413), E1616

and B1516, peak NO3 concentrations were within 0.3-1.0 mg/L (Figure 7.6b). The remaining tributaries - the New West Coulee (B1416), E1415 and B1212 not shown in

118

Figure 7.6 contained no detectable NO3 concentrations above the detection limit of 0.04 mg/L throughout the sampling periods.

10 5 CF Ck. E1717 E1716 8 4

3 6 /s) 3 (mg/L)

3 2 4 NO Flow (m

1 2

0 0 5/1/2007 8/1/2007 11/1/2007 2/1/2008 5/1/2008 8/1/2008 Date

1.6 5 12 Mile Ck. B1516 E1616 4 1.2

3 0.8 /s) 3

(mg/L) 2 3 NO 0.4 Flow (m 1

0.0 0

5/1/2007 8/1/2007 11/1/2007 2/1/2008 5/1/2008 8/1/2008 Date

NO3 concentrations in the Crowfoot Creek were typically below 1 mg/L but one sample

from April 2008 (spring baseflow) had 5.8 mg/L of NO3 (Figure 7.6a). Topographic

119

relief between the highest upland area and the lowest stream valley surrounding the Crowfoot Creek is the highest (240 m) (Chapter 2) among other sampled prairie streams. Overland flows on frozen ground on the prairies in early spring can mobilize solutes from within the soil horizon and transport them with snowmelt to lowland areas (Hayashi et al. 18 1998; Van der Kamp et al. 2003; Wright et al. 2009). Since δ OH2O (-17.3 and -17.6‰) 2 and δ HH2O (-143 and -144 ‰) values in the Crowfoot Creek in April and May 2008

(Appendix B-II: K4-5) were lower than the fall baseflow values, and NO3 was not detected during other baseflow periods, overland flow on frozen ground associated with snowmelt was the most likely cause for the NO3 peak observed in April 2008. In

addition, the NO3 concentration (0.8 mg/L) in the creek in June 2008, a heavy rainfall day, increased by over an order of magnitude above the background levels (Figure 7.6a) suggesting that direct runoff from the irrigation fields to the Crowfoot Creek occurred.

In E1717, NO3 concentrations increased to 3.0-7.0 mg/L during baseflow periods (Oct07, Nov07 and Apr08) (Figure 7.6a) suggesting that groundwaters infiltrating these

tributaries were contaminated with NO3. Similarly, E1616 showed elevated NO3 concentrations between 0.3 and 1.0 mg/L during both baseflow and runoff seasons

(Figure 7.6b). Increased NO3 concentrations in E1716 (Figure 7.6a) and B1516 (Figure 7.6b) coincided only with peak runoff in June 2008, but since only three samples were

collected (May-July 2008) from E1716, the role of baseflow NO3 cannot be assessed for

this particular tributary. Although some tributaries showed NO3 peaks corresponding to an overland flow event in June 2008, such conditions are not prominent and tend to be infrequent and short-lived on the prairies as the moisture source of these rainfall events usually comes from local or regional evapotranspiration (Strong 1999; Strong and Ardrossan 2000; Peng 2004).

Groundwaters contaminated with NO3 would most significantly induce elevated riverine

NO3 concentrations for an extended duration throughout baseflow periods from fall to spring (August to April). Overland flow on frozen or saturated ground in the spring

appeared to play, occasionally, an important role in flushing NO3 from the soil zone

120

especially for those tributaries draining the upland areas of the Blackfoot Plain (Chapter 2) from Carseland to the Bassano Dam. Tributary waters occasionally containing

baseflow or peakflow NO3 greater than 0.5 mg/L are all located between Cluny (378 km) and Bow City (482) near the physiographic transition from the Western to Eastern

Alberta Plains. Although NO3 concentrations from tributaries draining the prairie

irrigation districts were usually low, the occasional occurrences of high NO3 concentrations in the spring and fall provides adequate ground for suggesting that impacts of land use on the prairies is evident and may become further exacerbated by increased agricultural activities and feedlot operations.

7.6 Mass Loads of NO3 along the Bow River

The calculated annual mass load of NO3 at Lake Louise (0 km) was 0.09 kt increasing 3

4 fold at Canmore (99 km) (Table 7.2; Figure 7.7a). The NO3 load continued to increase downstream of Canmore (99 km) until reaching 1.37 kt which remained unchanged between Cochrane (179 km) and Calgary above the WWTPs (Table 7.2; Figure 7.7a).

Downstream of Calgary’s WWTPs, the annual NO3 load reached 8.92 kt at Carseland

(302 km) (Table 7.2; Figure 7.7a). This sharp >6-fold increase in the NO3 loads was caused by the 9.18 kt NO3 (Table 7.2; Figure 7.7a) input from WWTPs in Calgary. In

Figure 7.7b, NO3/Cl mole-equivalence ratios were used to trace the fate of Calgary’s

wastewater NO3 in the Bow River. The NO3/Cl ratios decreased from 0.37±0.10 in the wastewater effluent of Calgary’s WWTP at 230 km (TPBB) to around 0.15±0.06 at 248

km (FC) (Figure 7.7b). This suggests that instream NO3 removal had occurred within the monitored 18 km downstream of TPBB (230-248 km; Figure 7.7b), which is consistent with previous investigations by Vandenberg et al. (2005).

The low NO3/Cl ratio observed at 248 km (FC) was expected because the wastewater

effluent from TPFC (245 km) was characterized by a low NO3/Cl ratio of ~0.001. Given that the Cl concentrations in the effluents of the two WWTPs in Calgary were similar,

complete mixing of the effluents would result in a mixture with a NO3/Cl ratio around

0.18. The fact that all the NO3/Cl ratios from Carseland to Ronalane (302-571 km) were

121

nearly constant around 0.20 suggests that Calgary’s wastewater is the dominant source of

NO3 in the Bow River. The large NO3/Cl variations in Figure 7.7b may be partially due

to riverine diurnal cycle causing fluctuating NO3 concentrations throughout the day (Iwanyshyn et al. 2008).

Mass balance calculations shown in Figure 7.8 and Table 7.1 suggest that between

Calgary and Carseland (302 km), NO3 loads decreased by 1.24 kt after considering a combined loss of 0.69 kt to WID and BRID withdrawals (Figure 7.7a and 7.8). According to Table 7.2, the prairie tributaries were not likely a major contributor to the

NO3 load in the Bow River given the estimated NO3 load in the sampled tributaries was at least 1-2 orders of magnitude lower than that in the Highwood River (Table 7.2).

Although the maximum NO3 load from the Highwood River (0.19 kt) was one order of

magnitude higher than those from the Crowfoot Creek and E1717 (the next highest), NO3

from the prairies reaches could only account for, at most, 10% of the total NO3 load in the Bow River at Ronalane (571 km) (Table 7.2). The estimated tributary input throughout the prairie reaches was less than the 14% estimated for the mountain reaches from the Main Ranges to the Foothills and significantly lower than that of the Bonnybrook WWTP in Calgary (>77%).

Accurate NO3 load estimations were difficult to obtain downstream of the Bassano Dam.

Estimated riverine NO3 loads at Bow City (482 km) and Ronalane (571 km) were less exact than at those of other upstream sites because computations were complicated by

data obtained during irrigation periods, which plotted below the NO3 concentration-flow

calibration curve in Figure 7.4b. The conservative trend of annual NO3 loads in Figure

7.7a (green line) accounts for the headwater and wastewater NO3 loads plus amounts diverted at irrigation canals assumed losses to irrigation. Calculations show that instream

NO3 removal at Bow City (482 km) and Ronalane (571 km) would lower the NO3 loads to 6.8-9.7 kt and 5.4 – 8.3 kt respectively (Table 7.2). This gross estimate ascertained, under the assumption of maximum instream NO3 removal (blue dashed line in Figure

122

7.7a), that the NO3 load at Ronalane (571 km) would still be at least 5 times higher than those upstream of Calgary’s WWTPs. a

12 Calculated NO Loads 3 Conservative Trend BC After Max. NO Removal 3 CL RL 10 (kt) 3 8

WWTP

2 CC BN LL CM Annual Mass Loads of NO 0 WID BRID EID -2 0 100 200 300 400 500 600 Distance (km)

0.5

0.4

WWTP 0.3 0.27 /Cl 3

NO 0.2 CL CN BC SD RL 0.1 FC (Plume)

0.0 200 300 400 500 600 Distance (km)

123

LL 0.09

WID HW R. EID CM -0.04 0.19 -1.98 0.34

CC Calgary CL Bassano BC RL 1.37 1.41 8.92 Dam 9.90 9.32

Elbow R. WWTPs BRID 0.07 9.18 -0.65

Table 7.1 Estimated NO3 mass loads and unknown sources and sinks of NO3 along the Bow River. Percentage contributions from the Rocky Mountain headwaters, Calgary’s WWTPs and the prairie reaches were also calculated. Estimated Estimated Estimated Unknown Estimated Estimated Estimated NO3 Sources/ Sources/ Headwater WWTPs Prairie Stations Dist. Loads Sinks Sinks Input Input Input (km) (kt) (kt) (kt) (%) (%) (%) LL 0 0.09 100 0 0 CM 99 0.34 0.25 100 0 0 CC 179 1.37 1.03 100 0 0 BN 212 1.41 0.04 100 0 0 Elbow R. ~229 0.07 WID ~229 -0.04 WWTPs 230 9.18 HW R. 272 0.19 BRID ~301 -0.65 CL 302 8.92 -1.24 17 96 -13 EID 425 -1.98 BC 482 9.90 2.96 13 72 15 RL 571 9.32 -0.58 14 77 10

124

2007 2008 Average

Distance NO3 NO3 NO3 km [kt] [kt] [kt] The Bow River Lake Louise 0 0.1 0.1 0.09 ± 0.01 Canmore 99 0.4 0.3 0.34 ± 0.03 Cochrane 179 1.4 1.4 1.37 ± 0.15 Calgary 212 1.4 1.4 1.41 ± 0.15 Carseland 302 9.0 8.9 8.9 ± 0.36 Bow City 482 9.4 10.3 9.9 ± 0.82 (6.5 - 9.0) (7.0 - 10.2) (6.8 - 9.7) Ronalane 571 < 9.0 < 9.6 < 9.3 ± 0.87 (5.3 - 7.8) (5.5 - 8.7) (5.4 - 8.3)

Major Withdrawals and Inputs WID 230 -0.04 -0.05 -0.04 ± 0.005 BRID 301 -0.67 -0.62 -0.65 ± 0.03 EID 460 -2.1 -1.9 -1.98 ± 0.2 TPBBTP1 231 +9.4 +8.9 +9.17 ± 0.82 TPFCTP2 245 +0.01 +0.01 +0.01 ± 0.004 TP1+2 +9.4 +8.9 +9.18 ± 0.82

Prairie Tributaries Highwood River 272 < +0.2 <+ 0.3 < +0.26

Crowfoot Ck 406 - - <+0.05 E1717 481 - - < +0.1 E1716 487 - - <+0.02 E1616 498 - - <+0.01

B1516 503 - - <+0.003 B1416 (New West Coul.) 516 - - < +0.001 E1415 524 - - <+0.003

E1413 (12 Mile Ck.) 557 - - <+0.003 B1212 572 - - <+ 0.001

( ) - lower and upper estimations accounting for the uncertainty associated with possible instream NO3 removal during irrigation seasons (April – October). Italic - upper estimations made with assumed discharge and extrapolated NO3 concentrations.

125

7.7 Isotopic Compositions of NO3

7.7.1 NO3 in the Environment 18 15 The typical δ ONO3 and δ NNO3 values of the common NO3 sources in the environment 18 are shown in Figure 7.9. Atmospheric NO3 is characterized by high δ ONO3 values above 60‰ and synthetic NO3 fertilizers produced from atmospheric O2 and N2 are 18 15 characterized by δ ONO3 values between +18 and +22‰ and by δ NNO3 values of -5 to

+5‰ (Kendall et al. 2007). NO3 derived from nitrification of NH4 in fertilizer, soil and 18 15 manure has the same δ ONO3 values between -15 and +15‰, but the δ NNO3 values vary greatly between -10 and +25‰. Despite partially overlapping isotopic values, some NO3 15 sources are distinct since the δ NNO3 values from manure and septic waste derived NO3 are isotopically higher than those NO3 derived from soil, precipitation and fertilizers (Figure 7.9). Nitrate in waters of the Bow River Basin mainly plot within the isotopic range of soil and manure/wastewater derived NO3 with some prairie tributaries having 18 elevated δ ONO3 values between +10 and 30‰ (Figure 7.9).

100 Bow River Tributaries 90 0 km 99-212 km CF Ck. 80 Atmospheric NO - 3 302-571 km E1717 70 E1716 WWTP Others 60 Highwood R.

50 (‰) 40 NO3 O

18 30 1:2 δ NH + in fertilizer 4 NO - fertilizer 20 3 and precipitation 1:1 on cati 10 itrifi Den 2:1 0 Soil Manure and -10 NH + 4 Septic Waste -20 -20 -15 -10 -5 0 5 10 15 20 25 30 35

15 δ N (‰) NO3

126

7.7.2 Calgary’s Wastewater Effluents 15 18 The wastewater NO3 from TPBB had δ NNO3 and δ ONO3 values between 7.7 and 8.3‰, 15 and -9.5 and -9.7‰ respectively (Tables 7.3-7.4). The δ NNO3 values of TPBB (7.7 15 8.3‰) are similar to the δ NNH4 values from TPFC (8.0-9.1‰). The WWTPs in Calgary

discharge on average 3.15 kt N per year (Table 7.3) in the forms of NO3 and NH4. Because the majority (92%) of N at TPBB are removed via nitrification followed by denitrification, the remnant N (8%) discharged occurs in the form of NO3 whereas at

TPFC, the majority of the N (>99%) discharged remains in the untreated form of NH4 (Section 7.4). Of the total 3.15 kt of annual N discharge to the Bow River, 66% are from

NO3 at TPBB and 28% was derived from NH4 at TPFC (Table 7.3). The remaining 5.7% 15 of N in the form of NH4 released from TPBB had high δ NNH4 values between 13.2 and 21.8‰ (Table 7.3-7.4).

Based on isotope mass balance calculations according to the following equation expressed in a general form:

n ⎛ n ⎞ δ final = ∑( fi ×δi ); given that ⎜∑ fi = 1⎟ 1 ⎝ 1 ⎠

where f is the fraction of contributions from source i with an isotopic value of δi and n is the total number of sources making up the final mixture, the final isotopic composition of the mixture δfinal can be calculated. Comparisons based on isotope mass balance 15 calculations indicate that if the 5.7% NH4-N with elevated δ NNH4 values from TPBB 15 were nitrified and incorporated into the final wastewater mixture, the δ NNO3 value 15 would increase by up to 0.5‰ with respect to a final δ NNO3 value without incorporation

of nitrified NH4-N from TPBB. A wastewater containing 66.1% of NO3 and 33.9% of 15 nitrified NH4 would cause the δ NNO3 value of the mixed effluents to increase by 1.2‰ from 8.1‰ (0% nitrification) to 9.3‰ (100% nitrification) (Table 7.3; red arrow in Figures 7.15-7.17).

127

Table 7.3 Summary of results and the parameters used in the isotope mass balance calculations. The estimated range of isotopic values from conservative mixing of NO3 18 and nitrified NH4 are shown in italic. The δ ONO3 values (underlined) from presumed nitrification of NH4 are estimated using isotopic mass balance whereas the rest of the isotopic values are measured. Bonny Brook WWTP Fish Creek WWTP NO3-N NH4-N NO3-N NH4-N Total N Flux (kt/yr) 2.07 0.18 0.002 0.88 3.15 Mass Load % 66.0 5.7 0.1 28.2 100

15 δ N (‰) 7.7 to 8.3 13.2 to 21.8 9.2 to 12.7 8.0 to 9.1 +8.1 to +9.3 15 (as δ NNO3)

δ18O (‰) -9.5 to -9.7 -4.6 0.0 to 8.4 -4.6 -7.8 to -8.0 18 (as δ ONO3)

Table 7.4 Isotopic compositions of NO3 and NH4 for samples with significant amounts of NH4.

15 18 15 Station Dist. δ NNO3 δ ONO3 δ NNH4 Codes Station Names (km) Date (‰) (‰) (‰) TP1 Bonnybrook WWTP 230.8 4/4/08 7.7 -9.6 - (effluent) 5/10/08 8.3 -9.5 21.8 7/22/08 7.7 -9.7 13.2 W1 Bonnybrook 231.2 4/2/08 8.2 -10.0 18.2 5/8/08 8.0 -9.9 25.3 TP2 Fish Creek WWTP 245 4/4/08 10.2 1.8 8.3 (effluent) 5/10/08 12.7 8.4 9.1 7/23/08 9.2 0.0 8.0 W5 Fish Creek Park 248 8/30/07 8.5 -8.8 8.6 9/29/07 8.4 -8.8 5.5 10/25/07 7.7 -9.2 10.1 11/29/07 7.8 -8.1 9.9 2/8/08 7.7 -8.5 8.6 4/2/08 8.7 -8.2 9.1 5/8/08 7.6 -2.7 9.6 6/12/08 7.9 -5.8 1.1 7/22/08 7.9 -8.9 8.0 T8 E1415 524 5/9/08 6.3 1.0 9.0 6/11/08 17.8 4.2 11.3

128

Bacterially mediated nitrification of NH4 can be described by the following oxidation equations (Kendall 1998):

+ + NH4 + H2O → NH2OH + 3H (1)

- + NH2OH + O2 → NO2 + H2O + 2H (2)

- - + NO2 + H2O → NO3 + 2H (3)

where reactions (1) and (2) are mediated by Nitrosomonas, and (3) by Nitrobacter. Various microbial nitrification experiments demonstrated that the sources of oxygen in

NO3 come from H2O and O2 in a 2:1 ratio (Andersson and Hooper 1983; Kumar et al. 1983; Hollocher 1984). Based on this understanding of how the isotopic composition of

oxygen in NO3 was derived via microbially mediated oxidation reactions (1-3), the

oxygen isotope ratio of newly formed NO3 can be calculated as follows (Kendall 1998):

18 18 18 δ ONO3 = 2/3 δ OH2O + 1/3 δ OO2 (4)

18 Given that the average δ O value of Bow River H2O downstream of Calgary is -18.7‰ 18 (see Chapter 4) and δ O of atmospheric O2 is 23.5‰ (Kroopnick and Craig 1972), the 18 δ ONO3 value of NO3 from nitrification of wastewater NH4 was estimated to be -4.6‰

(underlined values in Table 7.3). Mixing 34% of NO3 (from NH4 nitrification) with a 18 18 δ ONO3 value of -4.6‰ with 66% of NO3 (from TPBB) having δ ONO3 values of around 18 -10‰ results in a mixture with δ ONO3 values of approximately -8‰ (Table 7.3).

7.7.3 NO3 in Prairie Tributaries 15 The δ NNO3 values of the Highwood River varied between +5 and +12‰ and when data 15 from the snowmelt and runoff season in May and June were excluded, the δ NNO3 values 15 appeared to increase with NO3 concentrations (Figure 7.10a). The δ NNO3 values during the snowmelt and rainfall season (May to July) were <+7.5‰ but throughout baseflow 15 periods (November to April), the δ NNO3 values of the Highwood River were

129

18 consistently >10‰ (Figure 7.10a). The δ ONO3 values were correlated with NO3 concentrations according to the equation: y = 20e(-x/0.15) (Figure 7.10b). This relationship 18 shows that as the NO3 concentration increased towards >1 mg/L, the δ ONO3 values approached 0 ‰ whereas when the NO3 concentrations were lower than detection limit 18 18 (0.04 mg/L), the δ ONO3 values increased to ≥10‰ (Figure 7.10b). These high δ ONO3 values were associated with low flow (<15 m3/s) during the irrigation period from July to 15 18 September in 2007 (Figure 7.10b). Low δ NNO3 and high δ ONO3 values during the snowmelt and rainfall period (Figure 7.10) indicate that nitrified soil organic N and NH4

were the dominant sources of NO3 in the Highwood River in late spring and early 15 summer. During irrigation and baseflow periods, δ NNO3 values above +10‰ and 18 δ ONO3 values near 0‰ suggest admixture of anthropogenic NO3 possibly derived from fertilizer, sewage and/or manure.

Tributaries with NO3 concentrations often >0.1 mg/L (solid triangles) include the Highwood River, the Crowfoot Creek, E1717 and E1616 (Figure 7.11). The small prairie 15 tributaries had δ NNO3 values between +5 and +12‰ (Figure 7.11a and b) but many had 18 18 high δ ONO3 values between +10 and +30‰ (Figure 7.11a and c). These high δ ONO3

values were associated with waters containing low NO3 concentrations below 0.2 mg/L 15 (Figure 7.11c). The δ NNO3 values among the tributaries showed no correlation with

NO3 concentrations (Figure 7.11b) but samples with high NO3 concentrations tended to 18 have low δ ONO3 values (Figure 7.11c).

18 The δ ONO3 values of Crowfoot Creek were typically higher than +23 ‰ but decreased 15 18 to +6.5 ‰ in June 2008 (Appendix B-II: K6). The δ NNO3 and δ ONO3 values of

baseflow NO3 in E1717 (Appendix B-II: L2-4) were similar to those of wastewater NO3 from TPBB in Calgary (Table 7.4), which is not typical for NO3 from tributary waters. 15 18 E1716 was characterized by δ NNO3 values between +8 and +9% but the δ ONO3 values varied from as high as +26.3‰ (Appendix B-II: M1) in May 2008 to as low as +3.6‰ two months later (Appendix B-II: M3). Contrary to E1716, E1616 showed variable 15 δ NNO3 values from as high as +10.4 ‰ in May to as low as +5.5‰ in June 2008

130

18 (Appendix B-II: N3-4). The δ ONO3 values of E1616 were among the lowest ranging between -2 and +1‰ (Appendix B-II: N2-3).

7/21/2008 9/29/2007 8/30/2007 4/4/2008 11/29/2007

10 10/25/2007

(‰) (‰) 8

NO3 6/10/2008 N

15 5/10/2008 δ 7/17/2007 6

6/19/2007

4 0.0 0.3 0.6 0.9 1.2 1.5 NO (mg/L) 3

7/17/2007

8/30/2007 10 9/29/2007 (‰) NO3 O 18 δ 5 7/21/2008 6/10/2008 4/4/2008 10/25/2007 (-x/0.15) 6/19/2007 5/10/2008 y = 20e 0 11/29/2007

0.0 0.3 0.6 0.9 1.2 1.5 1.8 NO (mg/L) 3

15 Figure 7.10 Plots for the Highwood River showing a) δ NNO3 vs. NO3 concentrations 18 and b) the δ ONO3 versus NO3 concentrations.

131

40 Highwood R CF Ck. E1717 E1716 30 E1616 E1516 B1416 (NW Coul) E1415 20 E1413 (12 Mile Ck) B1212

(‰) 10 NO3 O 18 δ 0

-10

-20 -5 0 5 10 15 20

15 δ N (‰) NO3 b

8 (‰) (‰) NO3

N 4 15 δ

-4 0.01 0.1 1 10 NO (mg/L) 3 c

16 (‰)

NO3 8 O 18 δ 0

-8

-16 0.01 0.1 1 10 NO (mg/L) 3

Figure 7.11 Plots for the Highwood River and the small prairie tributaries showing a) 15 18 15 18 δ NNO3 versus δ ONO3 b) δ NNO3 versus NO3 concentrations and c) δ ONO3 versus NO3 concentrations.

132

15 The δ NNO3 values of the prairie tributaries fluctuated within 8‰ but the maximum 18 15 δ ONO3 variation was greater than 40‰. Since these δ NNO3 values were similar within 15 14 ±4‰ to those of wastewater NO3 from Calgary, N/ N ratios of NO3 are not a suitable

indicator to distinguish NO3 soures coming from the irrigation districts. The high 18 δ ONO3 values however, may potentially be a better indicator if NO3 loads to the Bow

River from the prairies are sufficiently high. The isotopic composition of NO3 in E1717

is unique from other tributaries in that baseflow high in NO3 (Section 7.5) had the same

isotopic signatures as NO3 from TPBB (Figure 7.11). The water supply for a number of prairie communities is extracted from the EID canals and reservoirs, and the treated wastewater effluents of Tilley, Rosemary, County of Newell are returned to the Bow River via some EID canals (Bow River Basin Council 2005). The data suggest, but do not confirm, that some prairie tributaries (e.g. E1717) contained manure, septic and/or

wastewater derived NO3.

7.7.4 NO3 in the Bow River 15 The headwater NO3 at Lake Louise (0 km) was characterized by δ NNO3 values between 18 -0.1 and 3.5‰ and δ ONO3 values between 6.8 and 11.3‰ (Figure 7.12) falling within

the range typical for soil NO3 produced by ammonification and nitrification in natural forest ecosystems (Kendall et al. 2007; Figure 7.9). Leaching from the organic rich top soil horizons particularly during snowmelt periods is the most likely pathway by which soil-derived nitrate was introduced to the Bow River from the headwater catchments. Within the 230 km stretch of the Bow River between Lake Louise and Calgary above its 15 18 WWTPs, the δ NNO3 values increased to between 3.4 and 8.1‰, and the δ ONO3 decreased to values between -4.6 and 4.7‰ (Figure 7.12). The range of isotopic values for NO3 in the Bow River upstream of Calgary’s WWTPs suggests a mixture of soil

derived and wastewater-derived NO3. Since wastewater treatment plants in the Rocky Mountain reaches have tertiary treatment with bioreactors for nutrient removal (EPCOR

Utilities 2010), treated wastewater NO3 from Banff and Canmore is likely isotopically similar to that from TPBB. One baseflow sample in late November 2007 collected at 15 18 Canmore (99 km) had the same δ NNO3 and δ ONO3 values as those of effluent NO3 from

133

TPBB (Appendix B-I: B6; Table 7.4). It is therefore suggested that between Lake Louise

and Calgary, the Bow River contains NO3 from treated wastewater discharged along the Bow River at Lake Louise, Banff and Canmore. However, further study is needed to

confirm if wastewater derived NO3 from WWTPs upstream of Calgary has similar 15 18 δ NNO3 and δ ONO3 values as that in Calgary.

12 Bow River a/b WWTP 0 km 99 km 8 179 km 212 km

Wastewater Plume 4 248 km

Bow River b/w WWTP 302 km (‰) (‰) 0 378 km

NO3 482 km O 513 km 18 δ -4 571 km

Wastewater Effluent TPBB -8 TPFC

-12 02 4 6810 12 14 15 δ N (‰) NO3

15 Nitrate in the Bow River from Carseland (302 km) to Ronalane (571 km) had δ NNO3 18 values between 7 and 9 ‰ and δ ONO3 values between -6 and -10 ‰ (Figure 7.12).

These isotopic values are comparable to those of NO3 from TPBB within 1-2‰. This

indicates that wastewater is the dominant source of NO3 in the Bow River downstream of

Calgary. Although the majority of the isotopic values of NO3 from the prairie reaches of the Bow River was similar to wastewater values, the range of isotopic variations

134

downstream of the Bassano Dam (grey-black) was greater than those upstream (green) in Figure 7.12. The implication of this observation is further discussed in Section 7.8.

δ15N NO3 18 δ O NO3 10 12 WWTP Bassano Dam

8 8

4 6 (‰) (‰) 0

CM NO3 NO3

CC O N 4 18 15 δ δ BC -4

2 SD -8 CL CN RL LL 0 -12 0 100 200 300 400 500 600 Distance (km)

15 18 Figure 7.13 Average δ NNO3 and δ ONO3 values of the Bow River along its flow path between Lake Louise (0 km) and Ronalane (571 km).

Downstream of the WWTPs in Calgary, the wastewater plume at Fish Creek Park (248 15 18 km) was characterized by mean δ NNO3 values of +7.9±0.3 ‰ (n=10) and δ ONO3 values of -7.5± 0.3 ‰ (n=10) respectively (Figure 7.13). During snowmelt and rainfall periods, 18 δ ONO3 values in the wastewater plume were as high as -2.7‰ in May 2008 and -5.8 ‰ in June 2008 (Appendix B-II: V8-9). Excluding these two values, the averages were 15 18 +8.0±0.4 ‰ (n=8) for δ NNO3 and -8.3±0.4 ‰ for δ ONO3 (n=8). This shows that the isotopic compositions of NO3 in the wastewater plume are similar to NO3 in the effluent 18 most of the time. More positive δ ONO3 values in May and June reflect the increased

importance of soil derived NO3 during the spring snowmelt and rainfall period. The Bow River water downstream of Calgary at Carseland (302 km) and Cluny (378 km) was also

characterized by NO3 isotopic compositions similar to those at observed 248 km in

Calgary (Figure 7.13). The wastewater impact on the NO3 in the Bow River can be

135

15 traced isotopically to as far as Ronalane (571 km) near the mouth based on δ NNO3 and 18 δ ONO3 values. The dominating effect of this urban point source on riverine NO3 was well reflected in the narrow range of isotopic variations within ±2 ‰ (Figure 7.13) from samples taken throughout the 320 km along the Bow River between Calgary and Ronalane (571 km).

Figure 7.12 and 7.13 reveal that the Bow River can be separated into three characteristic 15 18 ranges based on δ NNO3 and δ ONO3 values. The Main Range headwaters at Lake 15 Louise (0 km) had the lowest average δ NNO3 value of +1.1 ± 0.1 ‰ (n = 10) and the 18 most positive δ ONO3 value of +9.6±1.1 ‰ (n=10) (Figure 7.13). From the Front Ranges 15 at Canmore (99 km) to the plains at northwest Calgary (212 km), δ NNO3 values 18 increased to +5.0 to +5.4 ‰ and the δ ONO3 values decreased to values between +0.7 and

+2.4 ‰ (Figure 7.13). The isotopic compositions of NO3 above Calgary’s WWTPs were 15 18 constrained to below +5.6 ‰ for δ NNO3 and above +0.7‰ for δ ONO3 (Figure 7.13). 15 18 From the WWTPs in Calgary to the Bassano Dam (>175 km), δ NNO3 and δ ONO3

values in the Bow River remained similar to those of NO3 in the wastewater plume at 248 km (Figure 7.13). Although an anomaly to the general trend was observed at Bow City

(482 km), the downstream isotopic values of NO3 at Scandia (513 km) and Ronalane

(571 km) usually remained similar to those of the wastewater plume NO3 at 248 km with 18 only slightly elevated δ ONO3 values above -7.5% (Figure 7.13).

7.8 Isotope Mass Balance Estimations 15 18 The baseflow (August-April) δ NNO3 and δ ONO3 values of the Bow River showed well

defined relationships with NO3 concentrations (Figure 7.14). Within a small range of

NO3 concentrations of less than 0.5 mg/L, NO3 between Lake Louise and Calgary 15 18 upstream of WWTPs showed large variations in δ NNO3 (0 to +8‰) and δ ONO3 (+11 to

-4‰) values (Figure 7.14; Section 7.2 and 7.7.3). Downstream of Calgary, NO3 concentrations varied within 1-8 mg/L but the isotopic values remained nearly constant 15 18 around +8‰ for δ NNO3 and -10‰ for δ ONO3 (Figure 7.14; Section 7.2 and 7.7.3).

136

10 y = 8 - 17e(-x/0.15) 8

6 (‰) (‰) NO3 N

15 4 δ

0 km 2 99-212 km 248-378 km 482-571 km 0

02 46 810 NO (mg/L) 3

8 0 km

(‰) 0 NO3 O 18 δ -4

-8 y = -10 + 26e(-x/0.37)

-12 02 46 810 NO (mg/L) 3

15 18 Figure 7.14 a) δ NNO3-NO3 concentration and b) δ ONO3-NO3 concentration relationships for the Bow River during baseflow periods from August 2007-April 2008.

15 18 The baseflow δ NNO3-δ ONO3 relationship of the Bow River is derived by combining the 15 (-[NO3]/0.15) 18 (-[NO3]/0.37) two equations δ NNO3 = 8-17e and δ ONO3 = -10 + 26e in Figure 7.14.

137

18 15 The empirically derived δ ONO3-δ NNO3 relationship for the Bow River in Figure 7.15 7.17 is:

0.41 ⎛ δ 15N − 8 ⎞ 18O 10 26 ⎜ NO3 ⎟ for { 0 ≤ δ15N ≤ 8} δ NO3 = − + ∗⎜ ⎟ NO3 ⎝17 ⎠

Isotope mass balance calculations can be effectively applied to the baseflow period from 15 18 August to April and the flow recession period in July because the δ NNO3 and δ ONO3 values were not as highly variable as those from May and June. With the highly variable 18 15 and scattered isotopic values excluded, deviations from the general δ ONO3-δ NNO3 trend were minimized and the accuracy of the isotopic mass balance estimations can be improved to account for most months (July to April) of the year.

In Figure 7.15, the flux-weighted average isotopic values of NO3 in the Bow River water

at Lake Louise (0 km) (end-member #1) represent the isotopic composition of NO3

produced in the natural forest soils. Wastewater NO3 labelled (end-member #2) in Figure

7.15 represents the major point source of NO3 in the Bow River Basin. If instream

nitrification of wastewater NH4 does not occur, conservative mixing of different

percentages of wastewater NO3 with soil derived NO3 would cause the isotopic values to fall on the mixing line shown in cyan between the two end-members in Figure 7.15.

However, if nitrification of wastewater NH4 is considered, the isotopic values of NO3 in the new wastewater mixture can shift along the red arrow from 0% nitrification at the base (#2) of the arrow to 100% nitrification at the tip of the arrow (Table 7.3).

Consequently, the isotopic composition of NO3 in the Bow River downstream of Calgary should fall on the pink mixing line connecting the natural source (#1) to the new end point at the tip of the arrow in Figure 7.15.

15 18 The fact that the isotopic composition of NO3 had high δ NNO3 and low δ ONO3 values between the 84-92% mixing range (Figure 7.15) revealed that riverine NO3 on the

prairies is most impacted by wastewater NO3 sources from Calgary. Since these data

138

point also plotted within the cyan and pink mixing lines, wastewater NO3 in the Bow

River downstream of Calgary contained partially nitrified NH4. Figure 7.15 also showed

that riverine NO3 downstream of Canmore (99 km) contained ≤50% of wastewater

derived NO3.

12 1. Forest Soils % 5 0 2 8 0%

% n 0 tio 5 a 4 ic rif 25% 99 it N 212 + Above Calgary: % g 179 5 in 7 x (‰) 0 ~50% Wastewater i M

NO3 % 50 O 18 δ -4 482 Below Calgary: % 84-92% Wastewater 75 -8 248-517 km g in ix M 0% 10 2. Wastewater -12 0 24 6 810 12 14 15 δ N (‰) NO3

18 15 Figure 7.15 Dual isotope diagram showing δ ONO3 and δ NNO3 values produced by mixing variable amounts of wastewater derived NO3 with the Bow River NO3 derived from forest soils (0km). The red arrow shows the extent of isotopic shift in wastewater derived NO3 under the influence of nitrification of wastewater NH4 sources (see Table 7.3; Section 7.7.2 for derivation of the wastewater nitrification trend).

15 18 Although the δ NNO3 and δ ONO3 values from the runoff period in spring (May and June) were more scattered and variable than those of baseflow values, most of the isotopic data in Figure 7.16 were within the typical range of the two end-member mixing

field. During the peak runoff period, wastewater derived NO3 accounted for 25-50% of

riverine NO3 upstream of Calgary whereas downstream of Calgary, wastewater NO3 sources accounted for 75-90% (Figure 7.16).

139

Above WWTP (99-212 km) Below WWTP (248-571 km) 12

n % o 25 ti a ic 8 rif 0% it N + 0% g 5 in ix 4 % M 25

75%

(‰) (‰) 0

NO3 % 50 O 18 δ -4

% 75 -8 g in ix % M 00 -12 1 02 4 6 810 12 14

15 δ N (‰) NO3

18 15 Figure 7.16 δ ONO3-δ NNO3 diagram showing variable ranges of wastewater contributions to the Bow River downstream of Calgary during the snowmelt and rainfall periods in May and June.

The fate of NO3 downstream of the Bassano Dam during irrigation season (July to 15 18 September) was also investigated. Deviation from the δ NNO3-δ ONO3 relationship that

characterizes the isotopic trend of NO3 in the Bow River were noted for individual water samples taken during the irrigation periods from July to September downstream of the Bassano Dam as shown in Figure 7.17. The Bow River water at Scandia (513 km) and 15 Ronalane (571 km) contained consistently low NO3 concentrations with elevated δ NNO3 18 and δ ONO3 values (Figure 7.18) along the 1:2 denitrification line (Böttcher et al. 1990; 15 18 Kool et al. 2007) in July of 2007 and 2008 (Figure 7.17). Plots of δ NNO3 and δ ONO3 values versus NO3 concentrations for samples taken downstream of the Bassano Dam

140

15 18 (482-571 km) showed that enrichment of N and O occurred inversely with NO3 concentrations (Figure 7.18).

12 Lake Louise 0 km

8 0.41 y = -10+26[(x-8)/17] ; { 0 ≤ x ≤ 8 } s) ly Ju ( 4 m k :2 1 1 7 -5 3 1 212 km 5

(‰) 0 NO3 O 18 δ -4 1 482 km 1:

-8 482-571 km (Aug-Sep) WWTP -12 02 4 6 810 12 14 15 δ N (‰) NO3

Figure 7.17 Average isotopic compositions of NO3 in the Bow River from Lake Louise 18 15 to Ronalane (0-571 km) along the δ ONO3-δ NNO3 curve linking the two end member sources represented by the isotopic compositions of NO3 at Lake Louise and NO3 from the WWTPs (red squares). Samples from downstream of the Bassano Dam during the second half of the irrigation season (July-September) were plotted separately to show the deviations from the general trend.

141

12 b/w Bassano Dam 7/17/2007 482 km 513 km 5/9/2008 571 km 10

(‰) 8 NO3

N 2 15 y = 9.5-0.33x (r =0.61 n=18) δ

6 peakflow in June

4 0 2 4 6 8 NO (mg/L) 3

5 7/17/2007

7/21/2008 0

(‰) May-June NO3

O -5 18 δ

y = -10+18e-x/0.7 -10

-15 0 2 4 6 8 NO (mg/L) 3

Figure 7.17 and 7.18 suggest that NO3 removal via instream or riparian denitrification downstream of the Bassano Dam is a possible explanation for the low NO3 15 18 concentrations with elevated δ NNO3 and δ ONO3 values during irrigation periods in July

when flow was low. In August and September, the isotopic compositions of NO3 for samples taken between Bow City (482 km) and Ronalane (571 km) fell either near the 1:1 denitrification line or near the wastewaters’ isotopic composition containing

completely nitrified NH4 (Figure 7.17). Although elevated isotopic values of NO3 plotted

142

along the denitrificaiton lines, both Figures 7.17 and 7.18 suggest that NO3 in the Bow River on the prairies is likely affected by several processes including denitrification, 15 18 mixing of agricultural return flows with high δ NNO3 and δ ONO3 values, and nitrification of wastewater NH4, which much had occurred prior to reaching the final reach of the river.

7.9 Summary

The annual NO3 mass loads in the Bow River upstream of Calgary’s WWTPs were low

~1kt but increased up to 7-8 fold downstream of Calgary. Calculations showed that NO3 mass loads downstream of Calgary from Carseland to Cluny were about 1kt lower than predicted assuming a conservative trend. Although riverine NO3 loads were difficult to estimate downstream of the Bassano Dam, mass load balance calculations show that

Calgary’s WWTPs contributed 77% of NO3 to the Bow River at Ronalane. For the Rocky Mountain reaches (the Elbow and the Highwood Rivers included), the combined

NO3 contribution was about 14% whereas NO3 from the prairie reaches may account for up to 10% of the total NO3 load at Ronalane.

The fact that NO3 concentrations increased with flows throughout the Rocky Mountain 15 18 reaches, coupled with δ NNO3 values between -0.1 and 3.5‰ and δ ONO3 values between

+6.8 and +11.3‰, confirms that soil NO3 is an important source in the forested upstream

catchments of the river basin. Downstream of Calgary, NO3 concentrations decreased with increasing flow, showing dilution of riverine NO3. The similarity between the isotopic compositions of NO3 in the river with those of the wastewater effluents

confirmed that NO3 loads to the Bow River on the prairies mainly came from Calgary’s WWTPs. Isotope mass balance estimations showed that most of the time, wastewater

NO3 accounted for greater than 84% of NO3 in the Bow River downstream of Calgary.

Even in the Bow River upstream of Calgary, up to 50% of the NO3 was wastewater

derived. This surprisingly high wastewater NO3 contribution in the partially forested

mountain catchments is predominantly due to the naturally low background NO3 levels.

143

The two end-member isotope mass balance approach is more effective than mass load

balance estimations. Source apportionment of NO3 using the two end-member isotopic mixing model for the Bow River downstream of Calgary (84-92 %) were higher than that estimated using mass loads (77%). Wastewater contribution to the Bow River upstream of Calgary cannot be quantified in this study using mass load balance as wastewater contribution to upstream reaches were not sampled; however, the isotope mass balance approach revealed that wastewater derived sources accounted for up to 50% of the riverine NO3 load upstream of Calgary. Quantification of riverine NO3 using a two-end member isotope mass balance approach proved to be very effective for the Bow River.

The isotopic composition of NO3 suggests that the riverine NO3 on the prairies could be

affected by denitrification, nitrification of wastewater NH4 and possibly NO3 sources 18 15 from the irrigation districts. Deviations from the δ ONO3-δ NNO3 relationship were found in samples taken from downstream of the Bassano Dam, particularly between Scandia and Ronalane (513-571 km) during irrigation periods from July to September, and during the brief snowmelt and rainfall period in May and June. Wastewater NO3

sources in the Bow River during the runoff period accounts for 25-50% of riverine NO3 load upstream of Calgary and 75-90% downstream of the city.

During the irrigation period in July when flow in the river was low, denitrification was detected in samples taken from downstream of the Bassano Dam. In August and September near the end of irrigation season, denitrification and complete nitrification of wastewater NH4 were observed within the same reach of the river. The effect of

denitrification, nitrification and unaccounted prairie NO3 sources on the Bow River downstream of the Bassano Dam appeared small compared to 84-92% of wastewater

derived NO3 in this reach of the river. Although these processes were observed qualitatively, isotopic values offer great merit for discerning sources and processes that otherwise cannot be detected using the conventional chemical and hydrometric data.

144

CHAPTER 8: CONCLUSIONS

Results and key findings from Chapter 4 to Chapter 7 are concluded in Sections 8.1 to 8.3. Discussion about future research is included in Section 8.4.

8.1 Isotope Hydrology of the Bow River In Chapter 4, sources of water in the Bow River were verified using the isotopic 2 18 composition of H2O. δ H and δ O values show that snowmelt from the Rocky Mountains is the main source of flows in the Bow River. During the peak runoff period in June, elevated δ2H and δ18O values with increasing flow along the length of the river indicate that the sources of runoff water in the headwater reaches are isotopically lower than the prairies reaches. River flow in the summer was affected by evaporation and the sudden increases in δ2H and δ18O values downstream of Scandia was partly caused by prairie tributaries discharging 2H and 18O enriched waters. The rather elevated δ2H and δ18O values observed at Ronalane (571 km) during the irrigation season from July to October suggest that the Bow River near the mouth was affected by tributary waters containing irrigation return flows and baseflows affected by evaporation. Since the wastewater effluents from Calgary had no significant impact on the isotopic composition 2 18 of H2O in the Bow River, δ H and δ O values is only useful for assessing the prairie tributary’s impact on the Bow River.

8.2 Major Ion Chemistry of the Bow River In Chapter 5, the major ion chemistry of the Bow River was investigated. The Bow River

had a Ca-Mg-HCO3 water, yet the chemical composition of the river was seasonally and spatially variable. Ion ratio interpretation revealed that the chemical composition of the

Bow River during snowmelt-rainfall period (May-July) is more Mg and HCO3 enriched

than baseflows, which are comparatively more Ca-Mg-SO4 enriched. This is consistent with the geochemistry of the Bow River favouring gypsum dissolution in the Rocky

Mountains. The river water evolved from Ca-Mg-HCO3 type towards compositions

elevated in Na, Cl, NO3 and SO4 with downstream distance. Elevated Na, Cl and NO3

145

levels in the river are clear evidence of anthropogenic impacts from wastewater effluents.

Increased Na and SO4 levels in the Bow River on the prairies especially downstream of the Bassano Dam were partially due to calcite precipitation in mid summer under the

effects of increased water temperature and active photosynthesis. Elevated Na and SO4 levels in river water from the prairie reaches were also influenced by discharges of Na

Mg-SO4 type tributary water. The major ion chemistry of the Bow River near the mouth

is a mixture of tributary waters of Na-Mg-SO4 and Ca-Mg-HCO3 types, Calgary’s

wastewater of Na-Ca-Cl type, and the Rocky Mountain headwaters of Ca-Mg-HCO3 type.

8.3 Source Identification and Apportionment for SO4 and NO3 in the Bow River

Isotopic techniques applied in Chapter 6 and 7 confirmed that SO4 was derived from

multiple anthropogenic and natural sources including wastewater SO4, dissolution of evaporite in the Rocky Mountains, oxidation of pyrite (mainly on the prairies), and soil and atmospheric derived sources. The δ34S and δ18O values suggest that tributary waters especially those located within EID near Brooks are contaminated with wastewater

derived SO4. The Bow River SO4 at the final reach is a mixture of about 53-63% from evaporite dissolution in the Rocky Mountains, 27-37% from combined oxidation of

reduced S and wastewater SO4 on the prairies, and 10% from Calgary’s WWTPs.

In contrast to SO4 where there are multiple sources with wide ranges of isotopic

signatures, riverine NO3 throughout the Bow River can be explained via a two end- 15 18 member mixing model. Chapter 7 shows that the δ NNO3 and δ ONO3 values of riverine

NO3 were mixtures of soil derived NO3 in forested catchments and wastewater derived

NO3 from WWTPs. Mass balance estimations reveal that wastewater sources account for

up 50% of the riverine NO3 loads upstream of Calgary and 84-92% downstream of

Calgary. Processes such as nitrification of wastewater NH4 and denitrification trends, undetectable by the conventional hydrometric and chemical techniques, were observed in the final 150 km reach of the river during the later part of the irrigation season from July to September.

146

8.4 Final Summary Given that >95% of the flow in the Bow River originates from the Rocky Mountains, where the water quality is relatively pristine in contrast to those downstream of Calgary where anthropogenic impact increased drastically, an understanding of natural versus anthropogenic controls on the water quality of the Bow River is essential for watershed management within the BRB. This study effectively used isotopic, hydrometric and chemical techniques to demonstrate that the water quality of the Bow River is impacted by various anthropogenic sources leading to increased Na, Cl, NO3 and SO4 loads.

This study successfully demonstrated that the application of simple mixing model using two to three end members that have distinct isotopic signatures was effective in

quantifying riverine NO3 loads, a mainly human-induced change to the water chemistry

of the Bow River. The estimates for SO4 were not as precise as those for NO3 because

efforts to apportion SO4 sources in the Bow River were hampered by the complex

overlapping isotopic signatures of SO4. Future research aimed at identifying the causes of SO4 isotopic variations may help further constrain the estimates.

8.5 Future Research A number of future research areas are identified in this study as follows: • Isotopic compositions of waters enriched in 2H and 18O in the Bow River at Ronalane is an indication of impact from irrigation return flow and prairie baseflow that had been subjected to evaporation. However, because tributary waters on the prairies are also groundwater-fed, effects of irrigation return flows should be verified by taking samples from return-flow irrigation canals at their outlets to the prairie tributaries.

• Conducting geochemical modeling for the Bow River including seasonal effects

and influences of Na-SO4 groundwaters may allow natural variations in the

isotopic compositions of SO4 to be delineated. This may help to separate the

anthropogenic and the natural components of the combined SO4 loads (27-37%)

147

estimated for the prairies, but will require detailed sampling of prairie groundwaters downstream of Calgary.

• The cause of isotopic variations in wastewater derived SO4, perhaps linked to the population’s seasonal dietary variations, is worth investigating. Natural variation associated with different hydrogeochemical sources remains a possible

explanation since the transition from a Ca-HCO3 rich groundwater west of the

Cordilleran-Laurentide till boundary to a Na-SO4 rich groundwater east of the divide occurs in Calgary upstream of WWTPs (Grasby et al. 2010).

• Sampling of wastewater effluents from other municipalities in the Rocky Mountains and the prairies may provide further verification for the estimated

wastewater NO3 load throughout the river. This will also confirm if

contamination of tributary waters with manure and/or wastewater derived SO4 on the prairies, particularly those in EID near Brooks is significant.

• Mass load estimations were likely underestimated as sampling on monthly basis was insufficient to capture the signal of non-point source contribution to the Bow River during the short and often sporadic runoff events. Concentration-flow relationships for this critical period between May and July require improved calibration with higher temporal resolution. This can be achieved by more frequent sampling on daily or weekly basis throughout the snowmelt and peakflow period.

• Leaching of NO3 through the soil zone of agricultural land may enhance sulphide

oxidation. Sulfides such as pyrite FeS2 can facilitate denitrification via the - 2- microbially catalyzed reaction: 30NO3 + 10FeS2 + 10H2O → 20SO4 + + 10FeOOH + 15N2 + 10H . Pyrite oxidation induced by tillage, which increases

exposure of sulphide minerals to air O2, was linked to increased SO4 concentrations in the lower reaches of the Oldman River (Rock and Mayer 2009).

148

Since denitrification in soil profiles was also observed in the river basin (Rock et al. 2007), further investigation on the role pyrite oxidation induced by NO3 leaching can enhance the understanding about the potential impact of surface water quality from the biogeochemical interaction of SO4 and NO3. A recent study by Smolder et al. (2010) suggested that redox reactions involving NO3 and

SO4 could be an important mechanism for provoking eutrophication in wetlands by mobilizing the existing phosphate in the system. If such processes were active in Alberta, it could have significant implication for landuse management and agricultural practices in the province.

149

REFERENCES

Alberta Agriculture Food and Rural Development. 2007. Irrigation in Alberta – Facts and Figures for the Year 2006. Lethbridge, Alberta.

Agriculture and Agri-Food Canada. 1998. The Canadian System of Soil Classification. 3rd ed. Soil Classification Working Group, National Research Council of Canada, Ottawa.

Alberta Economic Development Authority. 2008. Sustainable Water Management and Economic Development in Alberta. Alberta Economic Development Authority, Calgary.

Alberta Environment. 2002. South Saskatchewan River Basin Water Management Plan – Phase One. . [accessed 20-06-2010].

Alberta Environment. 2003. South Saskatchewan River Basin Water Management Plan - Phase Two Background Studies. 14-06-2007. . [accessed 01-03-2010].

Alberta Environment. 2004. Climate and Weather. . [accessed 01-03-2001].

Alberta Environment. 2006. Guiding Principles for Water Quality and Aquatic Ecosystem Monitoring. . [accessed 01-03-2010]

Alberta Environment. 2010. Instream Flow Needs Determination for the South Saskatchewan River Basin Report. . [accessed 20-06 2010].

Andersson, K.K. and A.B. Hooper. 1983. O2 and H2O are each the source of one O in - 15 NO2 produced from NH3 by Nitrosomonas: N-NMR evidence. FEBS Letters 164 (2): 236-240.

Appelo, C.A.J. and D. Postma. 2005. Geochemistry, Groundwater and Pollution. 2nd ed. A.A. Balkema Publishers. Amsterdam.

Aravena, R. Evans, M.L. and J.A. Cherry. 1993. Stable isotopes of oxygen and nitrogen in source identification of nitrate from septic systems. Ground Water 31 (2): 180-186.

Astrid, J., Kahnke, K., and K. Emeis. 2008. Isotopic composition of nitrate in five German rivers discharging into the North Sea. Organic Geochemistry 39: 1678-1689.

150

Atlas of Canada. 2009. Water Balance – Derived Precipitation and Evaporation. . [accessed 01-03-2011].

Back, W., Hanshaw, B.B., Plummer, L.N., Rahn, P.H., Rightmire, C.T. and M. Rubin. 1983. Process and rate of delolomitisation: mass transfer and 14C dating in a regional carbonate aquifer. Geological Society of America Bulletin 94: 1415-1429.

Balci, N., Shanks III, W.C., Mayer, B. and K.W. Mandernack. 2007. Oxygen and sulphur isotope systematics of sulfate produced by bacterial and abiotic oxidation of pyrite. Geochimica et Cosmochimica Acta 71:3796-3811.

Bird, J.B. 1972. The Natural Landscapes of Canada: a Study in Regional Earth Science. Wiley Publishers of Canada, Toronto.

Böttcher, J., Strebel, O., Voerkelius, S., and H.L. Schmidt. 1990. Using isotope fractionation of nitrate-nitrogen and nitrate-oxygen for evaluation of microbial denitrification in a sandy aquifer. Journal of Hydrology 114: 413-424.

Bow River Basin Council. 2005. Nurture, Renew, Protect: A Report on the State of the Bow River Basin. Bow River Basin Council, Calgary.

Brezonik, P.L., 1973. Nitrogen Sources and Cycling in Natural Water. U.S. Environmental Protection Agency, Washington, D.C. EPA 660/3-73-002.

Broughton, P.L. 1984. Sodium Sulphate of Western Canada. In: The Geology of Industrial Minerals in Canada (Guillet, G.R., Martin, W., eds.). Special Volume 29. The Canadian Institute of Mining and Metallurgy, Montreal, Quebec. 195-200.

Burgin, A.J. and S.K. Hamilton. 2007. Have we overemphasized the role of denitrification in aquatic ecosystems? A review of nitrate removal pathways. Frontiers in Ecology and the Environment 5 (2): 89-96.

Capaccioni, B., Didero, M., Paletta, C. and P. Salvadori. 2001. Hydrogeochemistry of groundwaters from carbonate formations with basal gypsiferous layers: an example from Mt Catria-Mt Nerone ridge (Northern Appenines, Italy). Journal of Hydrology 253: 14 26.

Cardenal, J., Benavente, J., and J.J. Cruz-Sanjulian. 1994. Chemical evolution of groundwater in Triasic gypsum-bearing carbonate aquifers (Las Alpujarras, southern Spain). Journal of Hydrology 161: 3-30.

151

Casciotti, K.L., Sigman, D.M., Hastings, M.G., Bohlke, J.K. and A. Hilkert. 2002. Measurement of the oxygen isotopic composition of nitrate in seawater and freshwater using the denitrifier method. Anal. Chem. 74: 4905-4912.

Catuneanu, O., Miall, A.D., and R.S. Arthur. 1997. Reciprocal architecture of Bearpaw T-R sequences, uppermost Cretaceous, Western Canada Sedimentary Basin. Bulletin of Canadian Petroleum Geology 45 (1): 75-94.

Charlesworth, H.A.K., Weiner, J.L., Akehurst, A.J., Bielenstein, H.U., Evans, C.R., Griffiths, R.E., Remington, D.B., Stauffer, M.R., and J. Steiner. 1967. Precambrian Geology of the Jasper Region, Alberta. Research Council of Alberta Bulletin 23.

Cheung, K. 2009. The Geochemistry of Shallow Groundwater and Produced Fluids Associated with Coalbed Methane (CBM) Exploration in Alberta, Canada. MSc. thesis, Department of Geoscience. University of Calgary, Calgary, Alberta.

Cheung, K. and B. Mayer. 2009. Chemical and Isotopic Characterization of Shallow Groundwater from Selected Monitoring Wells in Alberta: Part I. Alberta Environment. Edmonton, Alberta.

Christiansen, E.A. 1979. The Winsconsinan deglaciation of southern Saskatchewan and adjacent areas. Canadian Journal of Earth Sciences 16: 913-938.

City of Calgary. 2008. (18-09-2008). . [accessed 15-06-2010].

City of Calgary. 2009. Wastewater Treatment Plants Historical Data. Bonnybrook Wastewater Treatment Plant - City of Calgary Water Services. Calgary, Alberta.

City of Calgary. 2010. (27-05-2010). http://www.calgary.ca/portal/server.pt/gateway/PTARGS_0_0_780_237_0_43/http%3B/ content.calgary.ca/CCA/City+Hall/Business+Units/Water+Services/Construction+Project s/Pine+Creek/Pine+Creek+Project.htm [accessed June 20-2010].

Clark, I. and P. Fritz. 1997. Environmental Isotopes in Hydrogeology. 2nd ed. CRC Press LLC. Boca Raton, FL.

Clipperton, G.K., Koning, C.W., Mahoney, J.M. and B. Quazi. 2003. Instream Flow Needs Determination for the South Saskatchewan River Basin, Alberta, Canada. In: South Saskatchewan River Basin Water Management Plan – Phase Two: Background Studies. Alberta Environment. Calgary, Alberta

Deer, W.A., Howie, R.A. and J. Zussman. 1992. An Introduction to the Rock Forming Minerals. 2nd ed. Addison-Wesley. London.

152

Domenico, P.A. and F.W. Schwartz. Physical and Chemical Hydrogelogy. 1990. John Wiley and Sons Inc, Toronto.

Dowuona, G.N., A.R. Mermut, and H.R. and H.R. Krouse. 1992. Stable isotope geochemistry of sulfate in relation to hydrogeology in southern Saskatchewan, Canada. Applied Geochemistry 8: 255-163.

Drever, J.I. 1982. Geochemistry of Natural Waters. 1st ed. Prentice Hall Inc., Englewood Cliffs, N.J.

Dunne, T. and R.G. Black. 1970. Partial area contributions to storm runoff in a small New England watershed. Water Resources Research 6: 1296-1311.

Environment Canada. 2010. National Climate Data and Information Archive. (02-06 2010). . [accessed 01-07-2010].

EPCOR Utilities. 2010. Water and Wastewater in Alberta. . [accessed 20-06 2010].

Epstein, S. and T. Mayeda. 1953. Variation of O-18 content of waters from natural sources. Geochemica et Cosmochimica Acta 4 (5): 213-224.

Fennell, J. and L.R. Bentley. 1998. Distribution of sulphate and organic carbon in a prairie till setting: Natural versus industrial sources. Water Resources Research 34 (7): 1781-1794.

Ferguson, P.R., Weinrauch, N., Wassenaar, L.I., Mayer, B. and J. Veizer. 2007. Isotope constraints on water, carbon, and heat fluxes from the northern Great Plains region of North America. Global Biogeochemical Cycles 21, BG2023.

Freeze, R.A. and J.A. Cherry. 1979. Groundwater. Prentice Hall, Inc. Englewood Cliffs, NJ.

Fritz, P., Basharmal, G.M., Drimmie, R.J., Ibsen, J. and R.M. Qureshi. 1989. Oxygen isotope exchange between sulphate and water during bacterial reduction of sulphate. Chemical Geology 79: 99-105.

Galloway, J.N. Aber, J.D. Erisman, J.W. Seitzinger, S.P. Howarth, R.W. Cowling, E.B. and B.J. Cosby. 2003. The nitrogen cascade. BioScience 53 (4): 341-356.

153

Galloway, J.N., Dentener, F.J., Capone, D.G., Boyer, E.W., Howarth, R.W., Seitzinger, S.P., Asner, G.P., Cleveland, C.C., Green, P.A., Holland, E.A., Karl, D.M., Michaels, A.F., Porter, J.H., Townsend, A.R., and C.J. Vorosmarty. 2004. Nitrogen cycles: past, present, and future. Biogeochemistry 70: 153-226.

Garret, D.E. 2001. Sodium Sulfate: Handbook of Deposits, Processing and Use. Academic Press, San Diego.

Gehre, M., Hoefling, R., Kowski, P. and G. Strauch. 1996. Sample preparation device for quantitative hydrogen isotope analysis using chromium metal. Analytical Chemistry 68 (24): 4414-4417.

Gleick, P.H. 1996. Water Resources. In: Encyclopedia of Climate and Weather. (S.H. Schneider. Oxford University Press, New York. Vol.2, p. 817-823.

Government of Alberta. 2001. Sulphur Fertilizer Application in Crop Production. (01-12 2001). . [accessed 26-09-2010].

Government of Alberta. 2005. Agricultural Land Resource Atlas of Alberta – Solonetzic Soils of the Agricultural Area of Alberta. (01-09-2005). . [accessed 20 08-2010].

Government of Alberta. 2009. Agroclimatic Atlas of Alberta. (27-08-2009). . [accessed 20-08 2010].

Grasby, S.E. 1997. Controls on the Chemistry of the Bow River, Southern Alberta, Canada. Ph.D. thesis, Department of Geology and Geophysics. University of Calgary, Calgary, Alberta.

Grasby, S.E., Hutcheon, I. and H.R. Krouse. 1997. Application of the stable isotope composition of SO4 to tracing anomalous TDS in Nose Creek, southern Alberta, Canada. Applied Geochemistry 12: 567-575.

Grasby, S.E., Hutcheon, I. and L.M. McFarland. 1999. Surface-water-groundwater interaction and the influence of ion exchange on river chemistry. Geology 27 (3): 223 226.

Grasby, S.E. and I. Hutcheon. 2000. Chemical dynamics and weathering rates of a carbonate basin Bow River, southern Alberta. Applied Geochemistry 15: 67-77.

Grasby, S.E., Osborn, J., Chen, Z., and P.R.J. Wozniak. 2010. Influence of till provenance on regional groundwater geochemistry. Chemical Geology 273: 225-237.

154

Gravotta, C. 1997. Use of stable isotopes of carbon, nitrogen, and sulfur to identify sources of nitrogen in surface waters in the Lower Susquehanna River Basin, Pennsylvania. U.S. Geological Survey. Water-Supply Paper 2497.

Grossman, I.G. and C. Hartford. 1968. Origin of the sodium sulfate deposits of the Northern Great Plains of Canada and the United States. U.S. Geological Survey. USGS Prof. Paper 600-B: B104-109.

Hamilton, H.R. 1982. Bow River Water Quality 1970-1980. Alberta Environment Water Quality Control Branch. Calgary, Alberta.

Hamilton, W.N., Price, M.C., and C.W. Langenberg (comp.). 1999. Geological Map of Alberta, Alberta Geological Survey, Alberta Energy and Utilities Board, Map No. 236, Scale 1:1,000,000.

Hartman, J.H. and J.I. Kirkland. 2002. Brackish and marine mollusks of the Hell Creek Formation of North Dakota: evidence for a persisting Cretaceous seaway. In: The Hell Formation of the Northern Great Plains: An Intergrated Continental Record f the End of the Cretaceous (Hartman, J.H., Johnson, K.R., Nichols, D.J. eds). Geological Society of America Special Paper 361: 271-296.

Hayashi, M., Van der Kamp, G. and D.L. Rudolph. 1998. Water and solute transfer between a prairie wetland and adjacent uplands, 1. Water balance. Journal of Hydrology 207: 42-55.

Hein, F.J. and M.E. McMechan. 1994. Chapter 6 – Proterozoic and Lower Cambrian Strata of the Western Canada Sedimentary Basin. In: Geological Atlas of the Western Canada Sedimentary Basin (Mossop, G.D., Shetsen, I. eds). Canadian Society of Petroleum Geologists and Alberta Research Council, Calgary. Special Report 4: 57-67.

Hem, J.D., 1985. Study and Interpretation of the Chemical Characteristics of Natural Water. U.S. Geological Survey. Water-Supply Paper 2254.

Hendry, H.J., J.A. Cherry, and E.I. Wallick. 1986. Origin and distribution of sulfate in fractured till in southern Alberta, Canada. Water Resources Research 22 (1): 45-61.

Hendry, M.J., H.R. Krouse and M.A. Shakur. 1989. Interpretation of oxygen and sulfur isotopes from dissolved sulfates in tills of southern Alberta, Canada. Water Resources Research 3: 567-572.

Hoekstra, A.Y. 2006. The Global Dimension of Water Governance: Nine Reasons for Global Arrangement in Order to Cope with Local Problems. In: Value of Water Research Report Series No.20. UNESCO-IHE Institute for Water Education.

155

Hogberg, L.K. 2004. A Chemical, Biological and Isotopic Analysis of the Spatial Extent of Wastewater Effluent on Rivers in Southern Alberta, Canada. M.Sc. thesis, Department of Biological Science. University of Calgary, Calgary, Alberta.

Hogue, K.J. 2009. Assessing the Usefulness of Stable Isotope Data for Estimating Snowmelt Contributions to Runoff in the Headwaters of the South Saskatchewan River Basin, Alberta, Canada. MSc. thesis, Department of Geoscience. University of Calgary, Calgary, Alberta.

Hollocher, T.C. 1984. Source of oxygen atoms of nitrate in the oxidation of nitrite by Nitrobacter agilis and evidence against a P-O-N anhydride mechanism in oxidative phosphorylation. Archives of Biochemistry and Biophysics 233 (2): 721-727.

Holt, B.D., R. Kumar, and P.T. Cunningham. 1981. Oxygen-18 study of the aqueous- phase oxidation of sulfur dioxide. Atmospheric Environment 15: 557-566.

Hounslow, A.W. 1995. Water Quality Data - Analysis and Interpretation. Lewis Publishers, Florida.

Howarth R.W., Billen G, Swaney D., Townsend A., Jaworksi N., Lajtha K., Downing J.A.,Elmgren R., Caraco N., Jordan T., Berendse F., Freney J., Kudeyarov V., Murdoch P. and Zhu, Zhao-Liang 1996. Regional nitrogen budgets and riverine N and P fluxes for the drainages to the North Atlantic Ocean: Natural and human influences. Biogeochemistry 35: 75–139.

Howarth R.W., Sharpley A.W. and D. Walker. 2002. Sources of nutrient pollution to coastal waters in the United States: Implications for achieving coastal water quality goals. Esturies 25: 656-676.

Hydrogeological Consultants Ltd. 2002. Regional Groundwater Assessment. Prepared for the M.D. of Rocky View No. 44. (March). . [accessed 19-12-2009].

Hydrogeological Consultants Ltd. 2003. Regional Groundwater Assessment. Prepared for Wheatland County. (January). . [accessed 19-12 2009].

Hydrogeological Consultants Ltd. 2007a. Regional Groundwater Assessment. Prepared for Vulcan County. (March). . [accessed 19-12-2009].

Hydrogeological Consultants Ltd. 2007b. Regional Groundwater Assessment. Prepared for M.D. of Taber. (November). . [accessed 19-12-2009].

156

Iwanyshyn, M. Ryan, M.C. and A. Chu. 2008. Separation of physical loading from photosynthesis/respiration processes in rivers by mass balance. Science of the Total Environment. 390: 205-214.

Johnson, R.H. and S.O. Johnson (comp.). 1992. Formation Waters of Western Canada. Opus Petroleum Engineering Ltd. Calgary, Alberta.

Katvala, S.M. 2008. Isotope Hydrology of the Upper Bow River Basin, Alberta, Canada. MSc. thesis. Department of Geoscience. University of Calgary, Calgary, Alberta.

Keller, C.K. and G. Van der Kamp. 1988. Hydrologeology of two Saskatchewan tills II. Occurrence of sulfate and implications for soil salinity. Journal of Hydrology 101: 123 144.

Keller, C.K., Van der Kemp, G. and J.A. Cherry. 1991. Hydrogeochemistry of a clayey till 1. Spatial variability. Water Resources Research 27 (10): 2543-2554.

Kendall, C. 1998. Tracing nitrogen sources and cycling in catchments. In: Isotope Tracers in Catchment Hydrology (Kendall, C., McDonnell, J.J. eds). Elsevier, Amsterdam. p.519-576.

Kendall, C., Elliott, E.M. and S.D. Wankel. 2007. Tracing anthropogenic inputs of nitrogen to ecosystems. In: Stable Isotopes in Ecology and Environmental Science. 2nd ed. (Michener, R., Lajtha, K. eds). Blackwell Publishing, Malden, MA. 375-449.

Klassen, R.W. 1989. Quaternary geology of southern Canadian Interior Plains. In: Quaternary Geology of Canada and Greenland (Fulton, R.J. ed). Geological Survey of Canada, Ottawa, Canada. p. 138-173.

Kool, D.M., Wrage, N., Oenema, O., Dolfing, J., and J.W. Van Groenigen. 2007. Oxygen exchange between (de)nitrification intermediates and H2O and its implications for source - determination of NO3 and N2O: a review. Rapid Communication in Mass Spectrometry 21: 3569-3578.

Kroopnick, P. and H. Craig. 1972. Atmospheric oxygen: isotopic composition and solubility fractionation. Science 175 (4017): 54-55.

Krouse and Grinenko. 1991. Natural and Anthropogenic Sulphur in the Environment. (Scope 43). John Wiley and Sons. Rexdale, Canada.

Krouse, H.R. and B. Mayer. 2000. Sulphur and oxygen isotopes in sulphate. In: Environmental Tracers in Subsurface Hydrology (Cook, P.G., Herczeg, A.L. eds). Kluwer Academic Press, Boston. 195-231.

157

Kumar, S., Nicholas, D.J.D. and E.H. Williams. 1983. Definitive 15N NMR evidence that water serves as a source of ‘O’ during nitrite oxidation by Nitrobacter agilis. FEBS Letters 152 (1): 71-74.

Langmuir, D. 1997. Aqueous Environmental Geochemistry. Prentice Hall Inc., Englewood Cliffs, N.J.

Last, W.M. 1989. Continental brines and evaporites of the northern Great Plains of Canada. Sedimentary Geology 64: 207-221.

Last, W.M. 1992. Chemical composition of saline and subsaline lakes of the northern Great Plains, western Canada. International Journal of Salt Lake Research 1 (2): 47-76.

Last, W.M. and L.A. Slezak. 1987. Sodium sulphate deposits of western Canada: geology, mineralogy, and origin. In: Economic Minerals of Saskatchewan (Gilboy, C.F., Vigrass, L.W. eds). Special Publication Number 8. Saskatchewan Geological Society, Saskatchewan. 197-205.

Last, W.M. and F.M. Ginn. 2005. Saline systems of the Great Plains of western Canada; an overview of the limnogeology and paleolimnology. Saline Systems. 1: 1746-1448.

Legge, A.H., 1988. The Present and Potential Effects of Acidic and Acidifying Air Pollutants on Alberta's Environment. Critical Point I. Final Report. Prep. for the Acid Deposition Research Program by the Biophysics Research Group, Kananaskis Centre for Environmental Research, The University of Calgary, Alberta. ADRP-B-17-88

Lloyd, J.W. and J.A. Heathcote. 1985. Natural Inorganic Hydrochemistry in Relation to Groundwater. Clarendon Press. Oxford.

Farvolden, R.N., Meneley, W.A., Le Breton, E.G., Lennox, D.H. and P. Meyboom. 1963. Early Contributions to the Groundwater Hydrology of Alberta. Bulletin 12. Research Council of Alberta, Edmonton, Alberta.

Manwell, B.R. and M.C. Ryan. 2006. Chloride as an indicator of non-point source contaminant migration in the shallow alluvial aquifer. Water Quality Research Journal of Canada 41 (4): 383-397.

Meyboom, P. 1967. Interior Plains Hydrogeological Region. In: Groundwater in Canada (Brown, I.C. ed.). Economic Geological Report. No. 24. Geological Survey of Canada, Ottawa. 131-157.

Mossop, G.D., Shetsen, I., (comp.) 1994. Geological Atlas of the Western Canada Sedimentary Basin. Canadian Society of Petroleum Geologists and Alberta Research Council, Special Report 4, Calgary, Alberta.

158

Murphy, E.C. 1996. The sodium sulfate deposits of northwestern North Dakota. Report of Investigations No.99. North Dakota Geological Survey.

National Research Council. 2000. Clean Coastal Waters: Understanding and Reducing the Effects of Nutrient Pollution. National Academy Press, Washington.

Natural Resources Canada. 2008. (01-02-2008). Geoscape Canada. . [accessed 27-03-2010].

Ohte, N., Tayasu, I., Kohzu, A., Yoshimizu, C., Osaka, K., Makabe, A., Koba, K., Yoshida, N. and T. Nagata. 2010. Spatial distribution of nitrate sources of rivers in the Lake Biwa watershed, Japan: controlling facfors revealed by nitrogen and oxygen isotope values. Water Resources Research 46: W07505.

Ongley, E.D. and D.P. Blachford. 1982. Nutrient and Contaminant Pathways in the bow and Oldman Rivers, Alberta 1980-1981. Final Report to Environment Canada (Contract OSU80-00056). Department of Geography. Queen’s University, Kingston, Ontario.

Reardon, E.J., Mozeto, A.A. and P. Fritz. 1980. Recharge in northern clime calcareous sandy soils: soil water chemical and carbon-14 evolution. Geochim. Cosmochim. Acta 44: 1723-1735.

Paerl, H.W., Dennis R.L. and D.R. Whitall. 2002. Atmospheric deposition of nitrogen: implications for nutrient over-enrichment of coastal waters. Estuaries 25: 677-693.

Peng, H. 2004. Hydrogen and Oxygen Abundance Variation in Precipitation at Calgary, Alberta. Ph.D. thesis, Department of Physics and Astronomy. University of Calgary, Alberta.

Pettapice, W.W. (comp.). 1986. Physiographic Subdivisions of Alberta [map]. 1:1,500,000. Land Resources Research Centre, Research Branch, Agriculture Canada, Ottawa.

Piper, A.M. 1944. A graphical procedure in the geochemical interpretation of water analysis. Trans. Amer. Geophys. Union 25: 914-923.

Plummer, L.N. and W. Back. 1980. The mass balance approach: application to interpreting the chemical evolution of hydrologic systems. American Journal of Science. 280: 130-142.

Plummer, L.N., Busby, J.F., Lee, R.W. and B.B. Hanshaw. 1990. Geochemical modeling in the Madison aquifer in parts of Montano, Wyoming and South Dakota. Water Resources Research 26: 1981-2014.

Rabalais, N. 2002. Nitrogen in aquatic ecosystems. Ambio 31: 102-112.

159

Rabalais, N.N., Turner, R.E. and W.J. Wiseman. 2001. Hypoxia in the Gulf of Mexico. Journal of Environmental Quality 30: 320-329.

Reinelt, E.R. 1970. On the role of orography in the precipitation regime of Alberta. Albertan Geographer 6: 45-58.

Ricketts, B.D. 1989 (ed). Western Canada Sedimentary Basin: a Case History. Canadian Society of Petroleium Geologists. Calgary, Alberta.

Robinson, K.L., Valeo, C., Ryan, M.C., Chu, A., and M. Iwanyshyn. 2009. Modelling aquatic vegetation and dissolved oxygen after a flood event in the Bow River, Alberta, Canada. Can. J. Civ. Eng. 36: 492-503.

Rock, L. and B. Mayer. 2002. Isotopic assessment of sources and processes affecting sulphate and nitrate in surface water and groundwater of Luxembourg. Isotopes in Environmental Health Studies 38 (4): 191-206.

Rock, L. and B. Mayer. 2004. Isotopic assessment of sources of surface water nitrate within the Oldman River Basin, Southern Alberta, Canada. Water, Air, and Soil Pollution: Focus 4: 545-562.

Rock, L. and B. Mayer. 2006. Tracing nitrates and sulphates in river basins using isotope techniques. Water Science and Technology 53 (10): 209-217.

Rock, L., Ellert, B.H., Mayer, B. and A.L. Norman. 2007. Isotopic composition of tropospheric and soil N2O from successive depths of agricultural plots with contrasting crops and nitrogen amendments. Journal of Geophysical Research 112: D18303.

Rock, L. and B. Mayer. 2009. Identifying the influence of geology, land use, and anthropogenic activities on riverine sulphate on a watershed scale by combining hydrometric, chemical and isotopic approaches. Chemical Geology 262: 121-130.

Rueffel, P.G. 1968. Development of the largest sodium sulfate deposit in Canada. Canadian Institute of Mining and Metallurgy Bulletin 61: 1217-1228.

Sacks, L.A., Herman, J.S. and S.J. Kauffman. 1995. Controls on high sulfate concentrations in the Upper Floridan aquifer in southwest Florida. Water Resources Research 31: 2541-2551.

Schippers, A., Jozsa, P.-G. and W. Sand. 1996. Sulfur chemistry in bacterial leachig of pyrite. Applied and Environmental Microbiology 62: 3424-3431.

160

Sebilo, M., Mayer, B., Grably, M., Billiou, D., and A. Mariotti. 2004. The use of the 15 + 15 - ‘Ammonium Diffusion’ method for δ N-NH4 and δ N-NO3 measurements: comparison with other techniques. Environ. Chem. 1: 99-103.

Selby, M.J. 1982. Hillslope Materials and Processes. Oxford University Press, Oxford, England.

Sigman, D.M., Casciotti, K.L., Andreani, M., Barford, C., Galanter, M., and J.K. Bohlke. 2001. A bacterial method for the nitrogen isotopic analysis of nitrate in seawater and freshwater. Anal. Chem. 78: 4145-4153.

Slaymaker, H.O. 1974. Alpine hydrology. In: Arctic and Alpine Environments. (Ives, J.D., Barry, R.G. eds). Methuen, London. p. 134-155.

Smol, J.P. 2002. Pollution of Lakes and Rivers: A Paleoenvironmental Perspective. Oxford University Press, New York.

Smolders, A.J.P., Lucassen, E.C.H.E.T., Robbink, R., Roelofs, J.G.M. and L.P.M. Lamers. 2010. How nitrate leahing from agricultural lands provokes phosphate eutrophication in groundwater fed wetlands: the sulphur bridge. Biogeochemistry 98: 1-7.

Sosiak, A. 2002. Long-term response of periphyton and macrophytes to reduced municipal nutrient loading to the Bow River (Albert, Canada). Canadian Journal of Fisheries and Aquatic Science 59: 987-1001.

Stalker, A.MacS. 1961. Buried Valleys in Central and Southern Alberta. Paper 60-32. Department of Mines and Technical Surveys, Geological Survey of Canada, Ottawa, Canada.

Stednick, J.D. 1991. Wildland Water Quality Sampling and Analysis. Academic Press, San Diego, California.

Stevenson, FJ. 1972a. Nitrogen – element and geochemistry. In: Encyclopedia of Geochemistry and Environmental Sciences (Fairbridge, R.W., ed). Von Nostrand Reinhold Co., New York, p. 795-801.

Stevenson, FJ. 1972b. Nitrogen cycle. In: Encyclopedia of Geochemistry and Environmental Sciences (Fairbridge, R.W., ed). Von Nostrand Reinhold Co., New York, p. 801-806.

Strauss, H. 1993. The sulphur isotopic record of Precambrian sulfates: new data and a critical evaluation of the existing record. Precambrain Research 63: 225-246.

161

Strauss, H. 1994. The Neoproterozoic sedimentary sulphur cycle: evidence from the isotopic composition of marine evaporates and sedimentary pyrite. Mineral Mag. 58A: 881-882.

Strauss, H. 1997. The isotopic composition of sedimentary sulfur through time. Palaeogeography, Palaeoclimatology, Palaeoecology 132: 97-118.

Strong, G.S. 1999. A multi-scale conceptual model of severe thunderstorm. CMOS Bulletin SCMO 28: 45-54.

Strong, G.S. and A.B. Ardrossan. 2000. Review of prairie thunderstorms. CMOS Bulletin SCMO 31: 11-27.

Sullivan L. A., Bush R. T., McConchie D., Lancaster G., Haskins P. G., and M.W. Clark. 1999. Comparison of peroxide-oxidisable sulfur and chromium- reducible sulfur methods for determination of reduced inorganic sulfur in soil. Australian Journal of Soil Research 37: 255–266.

Taylor, B.E., Wheeler, M.C.and D.K. Nordstrom. 1984. Stable isotope geochemistry of acid mine drainage: Experimental oxidation of pyrite. Geochemica et Cosmochimica Acta 48: 2669-2678.

USEPA. 2003. Contaminant Candidate List: Regulatory Determination Support Document for Sulphate. U.S. Environmental Protection Agency (Office of Water). Washington, D.C.

USGS. 2006. National field manual for the collection of water-quality data – Chapter A4 collection of water samples. In: Book 9 – Handbooks for Water-Resources Investigations. U.S. Geological Survey, Reston, VA.

Vandenbery, J.A., Ryan, M.C., Nuell, D.D. and A. Chu. 2005. Field evaluation of mixing length and attenuation of nutrients and fecal coliform in wastewater effluent plume. Environmental Monitoring and Assessment 107: 45-57.

Van der Kamp, G., Hayashi, M. and D. Gallen. 2003. Comparing the hydrology of grassed and cultivated catchments in the semi-arid Canadian prairies. Hydrological Processes 17: 559-575.

Van Stempvoort, D.R. and H.R. Krouse. 1994. Controls of 18O in sulphate: a review of experimental data and application to specific environments. In: Environmental Geochemistry of Sulfide Oxidation. (Alpers, C.N., Blowes, D.W. eds). American Chemical Society, Washington, D.C., p.446-480.

162

Van Stempvoort, D.R., M.J. Hendry, J.J. Schoenau and H.R. Krouse. 1994. Sources and dynamics of sulphur in weathered till, Western Glaciated Plains of North America. Chemical Geology 111: 35-56.

Wallick, E. 1981. Chemical evolution of groundwater in a drainage basin of Holocene age, east-central Alberta, Canada. Journal of Hydrology, 54: 245-283.

Wallick, E. and R. Krouse. 1977. Sulphur isotope geochemistry of a groundwater generated Na2SO4/Na2CO3 deposit and the associated drainage basin of Horseshoe Lake, Metiskow, east central Alberta Canada. In: Proceedings of the Second International Symposium on Water-Rock Interaction. 1156-1164.

Water Survey of Canada. 2009. Water Level and Stream Flow Statistics. . [accessed 13 01-2009].

Weast, R.C. 1989. CRC Handbook of Chemistry and Physics. 70th ed. CRC Press, Boca Raton, FL.

Wohl, E. 2000. Mountain Rivers. American Geophysical Union, Washington, D.C.

World Health Organization (ed). 1978. Nitrate. Environmental Health Criteria 5. Geneva. [accessed October 25-2010].

World Health Organization (ed). 1986. Ammonia. Environmental Health Criteria 54. Geneva. [accessed October 25-2010].

Wright, N., Hayahi, M. and W.L. Quinton. 2009. Spatial and temporal variations in active layer thawing and their implication on runoff generation in peat-covered permafrost terrain. Water Resources Research 45: W05414.

Yonge, C.J., Goldenberg, L. and H.R. Hrouse. 1989. An isotope study of water bodies along a traverse of southwestern Canada. Journal of Hydrology 106: 245-265.

Zaporozec, A. 1972. Graphical interpretation of water quality data. Ground Water. 10: 32-43.

163

APPENDIX A: SUMMARY TABLE OF SAMPLING SITES

Label Station Names and Longitude Latitude Distance from Water Type Number of Abbreviations Lake Louise Samples (km) P1 Lake Louise (LL) 51.44271 -116.2129 0 Bow River 10 P2 Canmore (CM) 51.06304 -115.32356 99 Bow River 10 P3 Cochrane (CC) 51.18266 -114.48704 179 Bow River 11 P4 Calgary Bowness Park (BN) 51.07668 -114.17742 212 Bow River 11 P5 Carseland (CL) 50.83131 -113.41739 302 Bow River 11 P6 Bow City (BC) 50.43092 -112.22678 482 Bow River 10 P7 Ronalane (RL) 50.04814 -111.59033 571 Bow River 10 S1 Cluny (CN) 50.77142 -112.84411 378 Bow River 10 S2 Scandia (SD) 50.24642 -112.07686 513 Bow River 10 T1 Highwood River (HW) 50.78328 -113.82106 272 Tributary 11 T2 Crowfoot Creek (CF)/(W2220) 50.83458 -112.76278 406 Tributary 7 T3 E1717 50.43144 -112.22894 482 Tributary 7 T4 E1716 50.42194 -112.16808 487 Tributary 3 T5 E1616 50.33536 -112.15881 498 Tributary 5 T6 B1516 50.29011 -112.18139 503 Tributary 5 T7 New West Coulee (B1416) 50.22225 -112.09786 516 Tributary 6 T8 E1415 50.25167 -112.98439 524 Tributary 5 T9 12 Mile Coulee (E1413) 50.14928 -111.665 557 Tributary 6 T10 B1212 50.04294 -111.58542 572 Tributary 5 W0 Ogden Road (OD) 51.01418 -114.01241 230 Bow River 4 W1 Bonny Brook 51.00734 -114.02088 231 Wastewater Plume 2 W2 Heritage Road 50.98640 -114.02599 233 Wastewater Plume 4 W3 Dogwalk Park (DW) 50.96931 -114.02604 236 Wastewater Plume 2 W4 Bank Side (BS) 50.91646 -113.99305 243 Wastewater Plume 3 W5 Below Fish Creek (FC) 50.89628 -114.01051 248 Wastewater Plume 11 TP1 Bonny Brook WWTP 51.00993 -114.02025 231 Treated Wastewater 3 (TPBB) Effluent TP2 Fish Creek WWTP 50.91133 -114.00914 245 Treated Wastewater 3 (TPFC) Effluent 164

165

APPENDIX B: TABLES OF WATER ANALYSES

I – THE BOW RIVER

Location: Lake Louise (0 km) A1 A2 A3 A4 A5 A6 A7 A8 A9 A10 22-Jun- 16-Jul- 29-Aug- 26-Sep- 24-Oct- 28-Nov- 10-May- 13-Jun- 23-Jul- Constituents 07 07 07 07 07 07 4-Apr-08 08 08 08 Ion Concentrations (mg/L) Ca 21.5 20.9 21.1 21.7 22.1 23.8 23.0 23.2 20.9 20.2 Mg 8.7 8.7 8.3 8.6 8.8 9.6 9.4 9.3 8.4 8.2 Na 0.8 0.6 0.6 0.6 0.7 0.7 0.5 0.4 0.2 0.4 K 0.28 0.24 0.24 0.23 0.27 0.28 0.26 0.35 0.23 0.28

NH4 0.006 0.007 0.011 0.023 0.010 0.038 0.052 0.041 0 0.034

HCO3 89 86 83 93 90 104 95 101 87 89

SO4 12.2 13.0 12.8 12.9 12.8 13.4 15.0 12.3 13.0 13.9 Cl 0.2 0.2 0.2 0.3 0.4 0.4 0.4 0.3 0.2 0.2

NO3 0.20 0.18 0.14 0.10 0.21 0.30 0.31 0.12 0.41 0.46 TDS 133 129 126 137 135 152 144 147 130 133

Field Measurements pH 7.95 7.79 7.65 7.35 7.94 7.95 7.80 8.00 8.32 8.30 Temperature (oC) 10.08 13.52 10.14 8.25 4.68 0.03 0.06 3.69 7.88 13.37 Specific EC (µs/cm) 164 163 158 163 165 93 186 181 165 164

Dissolved O2 (mg/L) n/a 8.66 9.60 9.94 10.94 11.41 12.07 11.24 11.02 8.09

Isotopic Values (‰) 34 δ SSO4 18.0 18.1 16.5 19.3 19.0 18.8 19.3 18.9 19.7 19.4 18 δ OSO4 -6.3 -5.8 -6.8 -7.2 -6.4 -6.2 -7.3 -6.0 -6.6 -7.7 2 δ HH2O -151 -154 -150 -150 -153 -157 -152 -155 -152 -158 18 δ OH2O -19.6 -20.0 -19.9 -19.8 -19.8 -19.8 -19.9 -19.9 -19.9 -20.5 15 δ NNO3 2.1 0.6 3.5 0.4 -0.1 1.2 0.1 1.8 1.3 0.5 18 δ ONO3 9.5 11.3 10.0 6.8 8.2 8.8 7.7 7.5 8.6 9.7 13 δ CHCO3 n/a -4.9 -4.8 -4.6 -8.6 -5.0 -5.4 -6.6 -5.5 -6.7 166

Location: Canmore (99 km) B1 B2 B3 B4 B5 B6 B7 B8 B9 B10 22-Jun- 16-Jul- 29-Aug- 26-Sep- 24-Oct- 28-Nov- 10-May- 13-Jun- 23-Jul- Constituents 07 07 07 07 07 07 4-Apr-08 08 08 08 Ion Concentrations (mg/L) Ca 32.7 32.0 39.0 41.6 43.4 47.9 46.7 44.5 36.3 34.9 Mg 10.8 10.5 12.2 13.4 14.0 14.6 13.4 13.6 11.9 11.2 Na 1.2 1.1 1.6 1.7 1.7 1.4 1.2 1.5 1.0 1.1 K 0.38 0.34 0.35 0.42 0.41 0.46 0.41 0.50 0.36 0.41

NH4 0.016 0.004 0.022 0.020 0 0.004 0.064 0.009 0 0.046

HCO3 113 112 127 134 139 141 144 143 124 121

SO4 25.6 24.6 35.5 38.6 43.1 54.9 49.3 47.1 32.3 31.9 Cl 0.7 0.6 1.0 1.2 1.3 0.9 1.1 1.7 0.9 0.7

NO3 0.30 0.20 0.30 0.34 0.31 0.20 0.23 0.29 0.56 0.58 TDS 185 181 217 231 243 261 256 252 207 201

Field Measurements pH 8.02 8.07 8.02 8.03 8.28 8.35 7.83 8.57 8.38 8.36 Temperature (oC) 10.66 14.60 10.83 8.55 6.75 0.83 2.50 6.45 9.54 13.03 Specific EC (µs/cm) 230 228 270 290 306 334 322 318 265 254

Dissolved O2 (mg/L) n/a 8.69 10.32 10.68 11.16 12.04 12.71 11.84 9.98 9.53

Isotopic Values (‰) 34 δ SSO4 13.8 12.7 14.4 13.3 13.3 12.2 14.1 14.6 11.9 12.1 18 δ OSO4 -1.1 -1.2 1.4 1.5 1.9 2.6 2.7 2.0 -1.0 -0.3 2 δ HH2O -151 -153 -147 -149 -151 -151 -148 -150 -153 -153 18 δ OH2O -19.4 -19.6 -19.5 -19.5 -19.4 -19.3 -19.2 -19.4 -19.7 -20.3 15 δ NNO3 4.6 6.3 7.2 5.3 6.2 7.5 7.5 8.0 4.8 4.9 18 δ ONO3 2.5 3.3 -0.7 -3.1 -3.9 -10.2 3.9 -0.2 0.8 8.3 13 δ CHCO3 -6.4 -5.9 -5.9 -6.6 -7.2 -5.1 -6.0 -6.4 -6.0 -6.2 167

Location: Cochrane (179 km) C1 C2 C3 C4 C5 C6 C7 C8 C9 C10 22-Jun- 16-Jul- 29-Aug- 26-Sep- 24-Oct- 28-Nov- 10-May- 13-Jun- 23-Jul- Constituents 07 07 07 07 07 07 4-Apr-08 08 08 08 Ion Concentrations (mg/L) Ca 39.4 37.4 41.5 43.0 45.7 49.0 47.1 45.7 39.1 39.3 Mg 12.2 12.1 13.1 13.7 14.3 14.9 13.4 13.4 11.6 12.4 Na 2.5 2.1 2.2 2.4 2.5 2.4 1.7 2.4 2.7 2.0 K 0.64 0.48 0.49 0.50 0.53 0.57 0.48 0.68 0.73 0.51

NH4 0.046 0.012 0.016 0.027 0.003 0.033 0.045 0.014 0 0.017

HCO3 138 130 140 144 148 157 150 155 142 141

SO4 28.0 28.7 35.1 35.7 42.1 46.8 45.4 43.1 25.8 31.4 Cl 1.3 1.3 1.3 1.5 1.6 1.5 1.3 1.6 1.4 1.1

NO3 0.40 0.32 0.29 0.28 0.28 0.40 0.14 0.18 0.65 0.51 TDS 223 212 234 242 255 272 259 262 224 228

Field Measurements pH 8.08 8.22 8.27 8.22 8.35 8.28 8.00 8.55 8.37 8.50 Temperature (oC) 12.04 17.54 13.74 10.94 8.30 0.55 3.79 7.04 9.89 14.96 Specific EC (µs/cm) 278 267 289 300 316 339 3.24 325 278 284

Dissolved O2 (mg/L) n/a 8.99 9.66 9.94 11.15 12.87 12.53 11.29 12.00 9.47

Isotopic Values (‰) 34 δ SSO4 9.4 11.0 12.0 12.6 11.6 11.4 12.8 11.7 8.3 10.6 18 δ OSO4 -0.6 -1.1 -0.7 1.1 1.4 2.0 1.7 1.8 -0.2 -1.8 2 δ HH2O -149 -152 -146 -147 -148 -149 -147 -147 -148 -154 18 δ OH2O -18.9 -19.4 -19.3 -19.2 -19.2 -18.9 -19.4 -18.9 -19.4 -20.0 15 δ NNO3 3.7 4.9 6.2 5.7 5.6 6.4 7.0 8.1 5.3 3.4 18 δ ONO3 0.6 -0.4 0.4 -1.7 -0.4 -1.4 1.9 4.1 1.4 4.8 13 δ CHCO3 n/a -6.3 -6.2 -6.8 -7.1 -5.8 -5.6 -9.1 -7.8 -6.3 168

Location: Calgary at Bowness (212 km) D1 D2 D3 D4 D5 D6 D7 D8 D9 D10 20-Jun- 16-Jul- 29-Aug- 26-Sep- 24-Oct- 29-Nov- 10-May- 13-Jun- 23-Jul- Constituents 07 07 07 07 07 07 4-Apr-08 08 08 08 Ion Concentrations (mg/L) Ca 40.6 37.7 41.5 43.7 45.9 51.4 47.7 46.9 38.3 38.7 Mg 12.5 12.2 13.5 14.2 14.6 15.8 13.8 14.0 11.9 12.5 Na 3.8 2.2 2.8 3.3 3.1 3.0 2.1 3.8 4.5 2.2 K 0.85 0.48 0.54 0.60 0.58 0.61 0.52 0.77 1.09 0.54

NH4 0.009 0.006 0.030 0.005 0.004 0.009 0.014 0.025 0 0.022

HCO3 146 134 140 151 155 165 152 157 142 141

SO4 26.5 27.2 34.9 35.9 39.6 50.1 45.6 43.2 25.3 31.5 Cl 1.7 1.3 1.6 2.0 2.0 2.0 1.5 3.0 3.2 1.3

NO3 0.38 0.27 0.21 0.25 0.33 0.50 0.44 0.33 0.74 0.61 TDS 233 215 235 251 261 288 263 269 227 228

Field Measurements pH 8.13 8.28 8.43 8.36 8.33 7.89 8.06 8.71 8.33 8.46 Temperature (oC) 11.92 17.62 15.23 10.21 7.51 0.02 3.65 7.57 9.64 15.10 Specific EC (µs/cm) 280 270 293 315 326 297 333 336 285 285

Dissolved O2 (mg/L) n/a 8.88 10.47 9.74 11.29 12.66 12.06 10.99 11.14 9.19

Isotopic Values (‰) 34 δ SSO4 5.7 9.9 10.5 10.9 10.5 11.5 11.7 9.8 4.7 10.9 18 δ OSO4 -0.8 -0.9 -0.9 0.5 1.0 1.5 1.9 1.6 -0.8 -1.5 2 δ HH2O -146 -151 -147 -146 -146 -148 -146 -145 -148 -153 18 δ OH2O -18.8 -19.5 -19.2 -19.2 -19.1 -18.8 -19.3 -18.6 -19.3 -19.9 15 δ NNO3 3.5 6.9 6.6 6.3 5.9 5.8 7.4 9.5 5.1 5.3 18 δ ONO3 3.4 2.1 0.6 -0.2 -1.5 -1.4 1.1 -0.9 7.7 3.0 13 δ CHCO3 -8.1 -6.2 -6.3 -6.7 -7.6 -8.1 -5.8 -6.3 -8.4 -7.4 169

Location: Carseland (302 km) E1 E2 E3 E4 E5 E6 E7 E8 E9 E10 19-Jun- 17-Jul- 30-Aug- 28-Sep- 25-Oct- 29-Nov- 10-May- 10-Jun- 21-Jul- Constituents 07 07 07 07 07 07 4-Apr-08 08 08 08 Ion Concentrations (mg/L) Ca 45.1 40.9 45.3 46.7 48.8 n/a 50.7 48.9 41.4 43.2 Mg 14.3 13.7 15.4 16.2 16.6 n/a 15.7 15.4 13.1 14.4 Na 9.6 6.7 10.3 11.2 11.6 n/a 12.7 24.6 8.1 7.9 K 1.56 1.03 1.67 1.83 2.03 n/a 2.20 2.49 1.19 1.27

NH4 0.059 0.009 0.015 0.008 0.012 n/a 0.130 0.102 0 0.025

HCO3 164 140 152 157 166 180 155 162 150 161

SO4 35.9 38.6 48.2 52.0 50.2 n/a 62.1 57.2 35.9 39.6 Cl 3.9 4.3 6.5 7.2 7.8 n/a 10.6 24.5 4.3 4.5

NO3 1.03 1.32 2.29 3.99 4.01 4.94 6.05 4.35 1.40 0.94 TDS 275 247 282 296 307 n/a 315 340 255 273

Field Measurements pH 8.07 8.18 8.36 8.76 8.22 8.33 8.36 8.36 8.27 8.38 Temperature (oC) 13.13 20.06 15.72 11.52 7.13 0.02 4.25 8.11 12.32 17.98 Specific EC (µs/cm) 336 319 365 376 396 136 414 450 327 384

Dissolved O2 (mg/L) n/a 9.06 11.25 11.11 11.18 13.40 12.83 10.30 10.20 8.98

Isotopic Values (‰) 34 δ SSO4 2.9 6.4 7.1 6.5 7.2 8.0 8.9 3.7 0.9 4.4 18 δ OSO4 -0.7 -1.4 -0.6 0.2 -0.1 -0.5 1.2 0.7 -1.5 -1.9 2 δ HH2O -145 -149 -148 -145 -144 -145 -145 -147 -143 -149 18 δ OH2O -18.4 -19.4 -19.0 -18.8 -18.8 -18.8 -18.9 -19.0 -19.2 -19.5 15 δ NNO3 7.3 8.5 8.4 8.6 9.3 7.1 8.0 8.5 7.0 7.9 18 δ ONO3 -5.3 -8.3 -9.9 -9.5 -11.0 -10.6 -7.9 -7.1 -3.8 -9.3 13 δ CHCO3 n/a -7.1 -7.3 -7.2 -7.5 -6.8 -5.5 -7.5 -8.3 -7.2 170

Location: Bow City (482 km) F1 F2 F3 F4 F5 F6 F7 F8 F9 F10 19-Jun- 17-Jul- 30-Aug- 28-Sep- 26-Oct- 30-Nov- 9-May- 11-Jun- 22-Jul- Constituents 07 07 07 07 07 07 3-Apr-08 08 08 08 Ion Concentrations (mg/L) Ca 40.7 38.7 41.5 44.6 49.5 61.5 48.4 50.0 43.4 41.8 Mg 13.4 14.2 15.3 17.0 17.6 20.9 16.0 18.6 14.4 14.4 Na 10.9 10.7 12.0 15.8 15.3 16.8 17.3 40.5 18.4 10.2 K 1.38 1.21 1.59 1.82 1.97 2.36 2.05 2.55 1.60 1.33

NH4 0.069 0.008 0.014 0.007 0.009 0.146 0.033 0.018 0 0.029

HCO3 141 139 142 157 167 206 153 178 162 154

SO4 42.0 44.8 51.8 60.7 59.4 72.4 74.5 114.3 64.1 45.0 Cl 4.7 4.6 6.2 7.5 8.8 11.3 9.2 17.1 4.7 5.1

NO3 1.39 1.11 2.42 2.44 4.60 7.34 3.46 1.29 2.00 1.87 TDS 256 254 272 306 324 399 324 422 310 274

Field Measurements pH 8.04 8.55 8.40 8.48 8.50 8.34 8.01 8.60 8.31 8.53 Temperature (oC) 14.11 26.93 18.85 10.36 7.09 0.02 0.26 11.86 10.99 21.32 Specific EC (µs/cm) 323 329 354 394 418 483 423 546 390 352

Dissolved O2 (mg/L) n/a 8.59 10.49 10.95 11.84 14.23 15.03 10.66 9.80 8.68

Isotopic Values (‰) 34 δ SSO4 3.4 4.3 5.6 4.6 5.5 7.1 6.5 2.2 -1.4 4.5 18 δ OSO4 -0.9 -1.1 -1.0 -1.0 0.4 -0.7 0.2 -2.1 -2.6 -2.2 2 δ HH2O -149 -150 -144 -142 -143 -148 -143 -142 -142 -147 18 δ OH2O -18.9 -19.1 -18.8 -18.5 -18.4 -18.9 -19.0 -18.3 -18.9 -19.1 15 δ NNO3 5.9 10.2 8.9 9.0 7.6 6.6 8.2 9.1 7.0 7.9 18 δ ONO3 -7.6 -5.8 -7.7 -8.5 -10.5 -3.9 -8.1 -5.6 -0.9 -6.0 13 δ CHCO3 -7.6 -7.3 -7.8 -6.6 -6.6 -6.2 -5.7 -6.8 -8.3 -7.4 171

Location: Ronalane (571 km) G1 G2 G3 G4 G5 G6 G7 G8 G9 G10 19-Jun- 17-Jul- 30-Aug- 28-Sep- 26-Oct- 29-Nov- 9-May- 11-Jun- 21-Jul- Constituents 07 07 07 07 07 07 3-Apr-08 08 08 08 Ion Concentrations (mg/L) Ca 41.1 35.3 37.6 41.7 49.1 60.1 48.5 51.7 43.2 35.2 Mg 13.6 15.5 16.5 17.9 18.0 20.8 16.2 20.1 14.2 15.0 Na 10.0 14.0 14.5 16.7 15.3 16.6 18.9 37.6 13.1 11.8 K 1.26 1.46 2.01 2.08 2.09 2.30 2.10 2.66 1.35 1.48

NH4 0.050 0.014 0.019 0.005 0.004 0.216 0.022 0.048 0 0.037

HCO3 143 133 139 153 170 202 156 179 157 130

SO4 41.1 53.6 57.0 64.2 60.5 76.9 78.2 126.7 51.1 48.7 Cl 4.1 5.0 7.0 7.2 8.2 9.7 9.9 13.9 4.8 5.1

NO3 1.40 0.07 1.35 1.68 3.18 6.66 4.75 1.87 1.70 0.64 TDS 256 258 275 305 326 396 334 433 286 248

Field Measurements pH 8.15 8.79 8.72 8.25 8.32 8.49 7.81 8.47 8.35 8.98 Temperature (oC) 14.89 26.81 21.04 9.74 6.23 0.03 0.10 10.40 11.81 23.58 Specific EC (µs/cm) 318 338 354 394 423 426 437 707 363 330

Dissolved O2 (mg/L) n/a 9.77 12.10 9.65 10.32 13.73 15.36 9.16 9.36 13.30

Isotopic Values (‰) 34 δ SSO4 4.6 4.3 6.0 5.2 5.9 6.8 5.8 1.4 0.1 4.6 18 δ OSO4 -1.1 -1.4 -1.1 -0.8 -0.4 -1.0 0.3 -2.4 -1.7 -2.1 2 δ HH2O -147 -143 -136 -138 -140 -146 -144 -140 -142 -143 18 δ OH2O -18.8 -18.0 -17.4 -16.8 -17.5 -18.7 -19.0 -17.4 -18.8 -18.2 15 δ NNO3 6.4 11.4 9.8 9.1 7.1 7.5 8.6 11.0 7.4 9.3 18 δ ONO3 -8.5 3.3 -5.9 -8.5 -10.7 -10.2 -8.7 -2.5 -5.3 0.5 13 δ CHCO3 n/a -6.3 -6.1 -5.6 -6.7 -7.3 -5.6 -6.1 -7.9 -6.7 172

Location: Cluny (378 km) H1 H2 H3 H4 H5 H6 H7 H8 H9 H10 19-Jun- 17-Jul- 30-Aug- 28-Sep- 25-Oct- 29-Nov- 10-May- 10-Jun- 21-Jul- Constituents 07 07 07 07 07 07 3-Apr-08 08 08 08 Ion Concentrations (mg/L) Ca 45.6 39.5 44.4 46.5 48.6 57.6 48.3 49.9 44.0 45.1 Mg 14.9 13.8 16.0 16.8 17.3 18.8 15.8 16.5 14.2 14.7 Na 11.7 8.7 13.2 13.9 14.4 14.9 18.3 25.2 11.2 8.9 K 1.61 1.07 1.76 1.90 1.95 2.28 2.06 2.27 1.26 1.26

NH4 0.063 0.007 0.021 0.008 0.009 0.256 0.050 0.072 0.000 0.066

HCO3 165 139 151 163 166 195 153 168 161 163

SO4 42.2 41.3 55.5 54.8 56.5 75.9 70.2 80.4 46.0 42.5 Cl 4.3 4.2 7.1 7.5 8.6 10.4 12.3 12.7 4.4 4.6

NO3 1.29 1.05 3.12 2.73 4.37 6.20 4.40 3.75 0.45 0.52 TDS 286 249 292 307 317 381 324 358 282 281

Field Measurements pH 8.11 8.60 8.59 8.62 8.37 8.15 8.18 8.36 8.32 8.41 Temperature (oC) 13.59 23.58 17.12 11.91 8.17 0.10 0.03 8.44 11.00 19.05 Specific EC (µs/cm) 350 320 373 393 410 484 431 472 358 354

Dissolved O2 (mg/L) n/a 9.05 n/a 10.51 10.86 13.11 12.80 9.85 9.20 9.02

Isotopic Values (‰) 34 δ SSO4 1.5 5.4 5.6 5.6 5.9 7.4 7.3 3.6 -0.5 4.0 18 δ OSO4 -0.9 -1.4 -0.9 -0.6 -0.2 -0.4 1.2 -3.4 -1.4 -2.1 2 δ HH2O -147 -150 -146 -144 -144 -147 -144 -143 -144 -150 18 δ OH2O -18.6 -19.2 -18.8 -18.6 -18.7 -18.7 -18.6 -18.8 -18.9 -19.5 15 δ NNO3 6.8 10.8 8.8 9.0 8.6 7.2 8.7 7.8 8.2 8.0 18 δ ONO3 -7.4 -3.3 -9.7 -8.6 -10.3 -10.2 -7.5 -8.4 -4.4 -7.6 13 δ CHCO3 n/a -6.6 -7.1 -7.2 -6.9 -6.0 -5.8 -7.2 -8.1 -8.4 173

Location: Scandia (513 km) I1 I2 I3 I4 I5 I6 I7 I8 I9 I10 19-Jun- 17-Jul- 30-Aug- 28-Sep- 26-Oct- 30-Nov- 9-May- 11-Jun- 21-Jul- Constituents 07 07 07 07 07 07 3-Apr-08 08 08 08 Ion Concentrations (mg/L) Ca 41.2 38.0 40.5 43.7 48.9 78.4 48.6 49.8 46.5 38.3 Mg 13.5 14.4 15.3 16.9 17.4 26.8 16.3 18.7 16.2 14.3 Na 10.0 11.5 12.0 15.9 14.6 22.3 18.9 38.1 18.5 9.9 K 1.19 1.32 1.62 1.81 1.83 3.03 2.08 2.43 1.43 1.43

NH4 0.045 0.007 0.012 0.002 0 0.385 0.018 0.195 0 0.014

HCO3 144 140 140 154 166 261 155 167 164 146

SO4 42.1 46.8 52.3 61.4 59.0 99.6 79.7 116.1 74.8 44.7 Cl 4.0 4.5 6.0 7.4 7.8 15.4 9.9 14.3 4.7 4.5

NO3 0.94 0.42 1.85 0.99 3.66 7.89 4.81 1.94 1.63 1.35 TDS 257 257 270 302 319 515 335 408 327 260

Field Measurements pH 8.11 8.66 8.54 8.49 8.37 8.08 8.17 8.55 8.35 8.84 Temperature (oC) 13.89 26.45 19.79 10.36 6.16 0.03 0.03 11.22 11.63 23.30 Specific EC (µs/cm) 321 333 350 391 414 558 437 534 408 329

Dissolved O2 (mg/L) n/a 10.18 12.62 10.68 11.06 15.22 14.51 10.02 9.61 13.00

Isotopic Values (‰) 34 δ SSO4 3.2 5.2 4.8 4.7 6.0 6.8 5.9 1.4 -1.2 4.4 18 δ OSO4 -0.6 -1.9 -0.9 -1.9 0.3 -0.7 -0.3 -2.5 -3.0 -2.4 2 δ HH2O -147 -149 -143 -143 -143 -149 -144 -143 -145 -148 18 δ OH2O -18.9 -19.1 -18.8 -18.4 -18.5 -18.9 -18.5 -18.5 -18.9 -19.2 15 δ NNO3 6.8 11.0 9.5 9.2 7.7 7.1 8.4 8.9 7.6 8.6 18 δ ONO3 -6.0 2.8 -7.8 -5.5 -10.0 -10.1 -8.0 -4.8 -5.4 -2.0

13 174 δ CHCO3 n/a -6.5 -6.5 -6.4 -6.7 -5.9 -5.7 -6.2 -8.2 -6.2

175

II – TRIBUTARIES

Location: Highwood River (272 km) J1 J2 J3 J4 J5 J6 J7 J8 J9 J10 19-Jun- 17-Jul- 30-Aug- 29-Sep- 25-Oct- 29-Nov- 10-May- 10-Jun- 21-Jul- Constituents 07 07 07 07 07 07 4-Apr-08 08 08 08 Ion Concentrations (mg/L) Ca 47.1 49.2 57.1 58.5 59.7 68.3 59.3 52.7 45.8 55.1 Mg 13.0 14.5 16.7 16.7 16.9 19.8 17.0 15.3 12.4 14.7 Na 7.9 8.0 11.3 10.1 10.7 14.1 15.7 13.2 6.6 8.3 K 1.28 1.32 1.46 1.31 1.27 1.44 1.51 1.83 1.18 1.35

NH4 0.036 0.008 0.590 0.010 0.011 0.104 0.052 0.020 0.000 0.022

HCO3 173 177 191 199 201 261 195 187 161 203

SO4 31.9 42.0 60.9 56.9 63.1 75.4 76.3 55.1 33.3 41.1 Cl 1.5 1.8 2.6 2.4 2.7 7.4 5.3 4.9 1.4 1.7

NO3 0.25 <0.04 0.09 <0.04 0.20 1.32 1.13 0.40 0.26 0.25 TDS 276 294 342 345 356 449 372 330 262 326

Field Measurements pH 8.21 8.38 8.27 8.28 8.19 8.47 7.45 8.49 8.33 8.43 Temperature (oC) 14.01 25.44 14.89 7.67 5.37 0.04 0.01 6.10 9.01 16.83 Specific EC (µs/cm) 324 361 417 419 430 492 464 409 315 393

Dissolved O2 (mg/L) n/a 7.50 9.84 10.70 11.51 12.74 13.10 11.10 10.40 9.38

Isotopic Values (‰) 34 δ SSO4 -6.1 1.6 0.4 -0.3 0.7 0.9 1.4 -5.6 -8.2 -2.6 18 δ OSO4 -0.9 0.2 0.6 -0.7 0.5 0.0 1.3 0.2 -1.3 -2.1 2 δ HH2O -140 -143 -143 -138 -139 -144 -140 -146 -138 -140 18 δ OH2O -17.8 -18.2 -18.4 -18.0 -18.0 -19.3 -18.5 -18.7 -17.9 -18.7 15 δ NNO3 5.1 6.4 10.3 11.0 10.2 10.4 10.3 7.2 7.4 11.2 18 δ ONO3 2.2 18.0 11.0 9.7 3.1 -0.7 2.5 1.8 4.0 4.8 13

δ CHCO3 -7.3 -6.8 -7.5 -8.1 -7.8 -7.2 -7.8 -8.2 -8.8 -8.6 176

Location: Crowfoot Creek (406 km) K1 K2 K3 K4 K5 K6 K7 28-Sep- 26-Oct- 30-Nov- 10-May- 12-Jun- 22-Jul- Constituents 07 07 07 3-Apr-08 08 08 08 Ion Concentrations (mg/L) Ca 49.0 60.5 135.4 98.2 81.5 71.3 39.8 Mg 27.1 36.4 73.2 54.8 47.6 51.6 24.4 Na 74.1 104.2 281.1 397.0 365.9 295.8 73.9 K 3.38 4.54 9.39 10.10 8.66 8.01 2.86

NH4 0 0.055 0.047 0.015 0.018 0 0.025

HCO3 214 269 522 418 361 319 202

SO4 181.7 280.0 716.7 913.0 872.6 739.0 171.3 Cl 13.6 16.8 37.9 33.9 29.0 32.8 13.9

NO3 <0.04 <0.04 <0.04 5.75 <0.04 0.77 0.29 TDS 563 771 1776 1931 1766 1518 528

Field Measurements pH 8.60 8.38 7.92 7.94 8.63 8.26 8.83 Temperature (oC) 11.08 5.67 0.20 0.55 8.78 12.98 23.81 Specific EC (µs/cm) 716 960 2061 2390 1733 1860 681

Dissolved O2 (mg/L) 12.22 11.69 11.96 16.84 8.82 8.47 10.90

Isotopic Values (‰) 34 δ SSO4 -2.0 -1.1 -1.7 -1.7 -2.0 -2.1 -1.3 18 δ OSO4 -1.7 -1.4 -3.6 -5.2 -2.8 -1.6 -1.9 2 δ HH2O -134 -130 -134 -143 -144 -132 -140 18 δ OH2O -16.3 -15.9 -16.0 -17.3 -17.6 -16.5 -17.2 15 δ NNO3 3.8 11.9 6.7 7.1 6.3 10.6 6.6 18 δ ONO3 23.0 30.0 24.5 23.5 23.5 6.5 25.1 13

δ CHCO3 -7.2 -7.7 -6.6 -8.2 -8.7 -10.6 -10.3 177

E1717 E1716 Location: (481 km) (487 km)

L1 L2 L3 L4 L5 L6 L7 M1 M2 M3 28-Sep- 26-Oct- 30-Nov- 9-May- 11-Jun- 22-Jul 9-May- 12-Jun- 22-Jul- Constituents 07 07 07 3-Apr-08 08 08 08 08 08 08 Ion Concentrations (mg/L) Ca 50.4 52.5 61.8 46.6 65.1 47.3 46.8 136.2 80.3 90.7 Mg 24.1 19.6 21.1 15.9 33.8 20.3 19.8 98.6 88.4 49.7 Na 66.1 27.8 17.1 21.0 142.9 70.0 34.1 463.4 602.9 208.2 K 4.93 2.25 2.45 2.03 5.57 5.13 7.25 7.31 8.51 2.72

NH4 0 0.030 0.169 0.027 0.019 0 0.021 0.029 0 0.029

HCO3 191 175 206 152 219 177 193 290 168 240

SO4 180 99 75 85 384 190 111 1501 1733 743 Cl 9.7 9.3 11.3 9.2 15.0 6.6 5.8 19.5 4.5 5.0

NO3 <0.04 4.46 6.46 3.18 0.11 0.43 0.25 0.06 4.43 0.31 TDS 526 390 402 335 865 517 417 2515 2690 1340

Field Measurements pH 8.71 8.25 8.16 8.03 8.51 7.96 8.21 8.24 7.87 8.38 Temperature (oC) 11.42 6.77 0.02 0.35 12.85 11.60 22.42 10.55 10.97 20.17 Specific EC (µs/cm) 673 670 474 427 1112 692 526 2963 3328 1578

Dissolved O2 (mg/L) 11.06 11.83 15.22 15.02 10.09 7.02 7.92 10.71 7.67 8.94

Isotopic Values (‰) 34 δ SSO4 -4.5 1.4 7.0 4.4 -8.3 -7.4 -2.9 -11.0 -13.4 -10.1 18 δ OSO4 -2.4 -1.6 -0.7 -1.3 -4.9 -3.5 -4.2 -8.5 -8.6 -6.6 2 δ HH2O -139 -142 -149 -141 -143 -137 -141 -141 -136 -145 18 δ OH2O -16.9 -18.4 -18.9 -18.4 -18.3 -17.6 -18.2 -17.6 -17.7 -18.0 15 δ NNO3 10.1 7.9 7.0 8.7 12.4 5.2 8.3 8.4 11.3 9.0 18

δ ONO3 14.4 -10.3 -10.1 -6.9 10.6 15.6 20.9 26.3 1.5 3.6 178 13 δ CHCO3 -9.4 -7.0 -6.7 -6.0 -6.8 -10.7 -12.0 -9.6 -11.5 -11.8

E1616 B1516 Location: (498 km) (503 km)

N1 N2 N3 N4 N5 O1 O2 O3 O4 O5 28-Sep- 26-Oct- 9-May- 12-Jun- 22-Jul- 26-Oct- 9-May- 11-Jun- 22-Jul Constituents 07 07 08 08 08 07 3-Apr-08 08 08 08 Ion Concentrations (mg/L) Ca 42.6 72.4 49.8 57.8 39.8 79.9 75.6 83.3 52.1 50.5 Mg 18.8 25.9 18.8 24.4 16.1 37.1 33.6 41.4 34.9 43.3 Na 16.2 25.3 30.7 29.7 12.4 133.2 117.2 157.0 155.4 151.6 K 3.85 4.18 3.50 8.90 3.88 4.96 4.05 4.92 5.61 4.87

NH4 0.011 0.035 0.048 0.043 0.028 0.011 0.051 0.017 0.003 0.029

HCO3 161 252 163 188 165 374 344 400 307 297

SO4 65 115 97 124 47 311 278 350 340 373 Cl 7.6 8.0 17.1 17.4 5.1 8.8 7.7 9.6 9.3 11.4

NO3 <0.04 0.68 1.01 0.46 0.24 <0.04 <0.04 <0.04 0.51 <0.04 TDS 315 503 381 451 290 949 860 1046 904 932

Field Measurements pH 8.67 8.29 8.32 8.00 7.90 8.34 7.99 8.47 8.21 8.79 Temperature (oC) 11.50 7.61 11.20 10.27 19.73 3.31 0.09 11.34 10.92 23.83 Specific EC (µs/cm) 398 639 514 605 373 1134 1025 1250 1114 1141

Dissolved O2 (mg/L) 12.43 13.51 9.93 9.60 7.13 13.63 12.36 10.84 9.27 13.48

Isotopic Values (‰) 34 δ SSO4 5.1 -0.9 2.1 -6.4 3.9 -4.2 -4.0 -2.5 -4.6 -3.1 18 δ OSO4 -0.6 -3.2 -1.7 -3.5 -2.7 2.2 1.0 1.5 4.5 2.4 2 δ HH2O -138 -140 -141 -137 -141 -125 -125 -129 -121 -111 18 δ OH2O -17.0 -17.9 -17.6 -17.1 -18.1 -14.2 -14.1 -15.3 -14.3 -11.9 15 δ NNO3 5.0 9.0 10.4 5.5 5.9 7.8 -2.8 7.2 10.4 nd 18

δ ONO3 21.7 1.2 -1.9 10.8 5.4 29.9 13.1 26.4 29.9 nd 179 13 δ CHCO3 -7.1 -10.9 -5.6 -11.2 -11.4 -10.6 -10.6 -9.6 -9.9 -8.5

B1416 E1415 Location: (516 km) (524 km)

P1 P2 P3 P4 P5 P6 Q1 Q2 Q3 Q4 Q5 28-Sep- 26-Oct- 9-May- 11-Jun- 21-Jul 28-Sep- 26-Oct- 9-May- 11-Jun- 21-Jul- Constituents 07 07 3-Apr-08 08 08 08 07 07 08 08 08 Ion Concentrations (mg/L) Ca 44.0 50.7 62.3 53.5 55.3 43.7 39.9 68.8 55.2 45.1 33.9 Mg 28.9 43.1 35.4 30.7 32.1 27.1 16.9 29.4 21.4 23.2 14.0 Na 59.4 79.0 63.8 65.1 63.9 58.4 13.9 20.4 25.5 28.7 9.7 K 4.51 11.05 10.75 5.60 12.52 4.81 2.16 5.91 4.64 33.46 1.29

NH4 0 0.008 0.016 0.017 0.021 0.025 0 0.185 0.277 0.432 0.110

HCO3 182 277 156 206 191 191 149 250 168 181 140

SO4 175.7 210.5 282.9 202.6 230.5 179.8 54.1 109.6 111.2 113.3 41.2 Cl 11.6 20.0 15.5 12.9 12.8 11.1 7.2 10.9 17.8 25.5 4.5

NO3 <0.04 <0.04 <0.04 <0.04 1.49 0.25 <0.04 0.08 0.31 0.48 0.24 TDS 506 691 627 577 599 517 283 495 404 451 245

Field Measurements pH 8.43 8.23 8.06 8.36 8.23 8.71 8.15 7.70 7.91 7.93 8.45 Temperature (oC) 10.13 4.01 2.54 10.01 11.38 24.48 9.66 4.14 8.11 12.44 24.27 Specific EC (µs/cm) 658 874 832 746 785 667 368 627 537 590 316

Dissolved O2 (mg/L) 11.13 11.55 12.68 10.34 9.98 8.28 9.75 6.86 9.79 8.23 7.66

Isotopic Values (‰) 34 δ SSO4 0.1 3.9 -4.6 -0.1 -4.0 -0.2 5.2 0.4 1.5 -2.0 4.0 18 δ OSO4 -0.4 3.7 -4.2 -0.9 -3.0 -0.6 -0.8 -2.4 -2.1 -1.4 -2.1 2 δ HH2O -120 -95 -143 -116 -126 -117 -138 -133 -139 -136 -142 18 δ OH2O -13.7 -9.4 -16.7 -13.5 -15.2 -14.1 -17.5 -16.4 -17.8 -17.2 -18.5 15 δ NNO3 - 9.5 8.0 7.6 - 7.9 3.7 6.3 17.8 18 δ ONO3 - 28.9 25.0 24.6 - 1.2 14.6 1.0 4.2 13 δ CHCO3 -6.2 -6.2 -4.5 -3.3 -9.4 -7.7 -6.1 -10.1 -6.6 -11.4 -7.1

180

E1413 B1212 Location: (557 km) (572 km)

R1 R2 R3 R4 R5 R6 S1 S2 S3 S4 S5 28-Sep- 11-Jun- 28-Sep- 11-Jun Constituents 07 26-Oct-07 3-Apr-08 9-May-08 08 21-Jul-08 07 26-Oct-07 9-May-08 08 21-Jul-08 Ion Concentrations (mg/L) Ca 32.5 41.5 43.7 40.5 24.3 25.7 36.4 34.4 51.1 41.0 29.3 Mg 21.6 22.2 19.4 24.3 21.3 21.4 27.7 33.3 30.3 29.6 27.6 Na 20.9 21.7 21.5 27.7 24.1 24.7 57.8 71.5 62.1 61.0 61.9 K 3.52 4.36 7.04 9.66 2.91 3.22 4.02 6.77 5.00 4.89 4.49

NH4 0.021 0.036 0.029 0.129 0.005 0.034 0.005 0.002 0.024 0.005 0.042

HCO3 150 177 204 223 118 141 161 156 203 183 153

SO4 69.7 73.6 49.0 54.0 85.8 73.0 170.9 232.4 192.5 177.1 185.3 Cl 8.9 9.2 10.2 15.0 8.6 8.7 11.2 15.2 12.2 12.1 11.9

NO3 <0.04 0.08 <0.04 0.19 <0.04 0.24 <0.04 <0.04 0.05 <0.04 <0.04 TDS 307 349 355 394 285 298 469 549 557 509 474

Field Measurements pH 8.54 8.10 8.11 8.08 9.52 9.78 8.10 8.04 8.47 8.49 9.31 Temperature (oC) 9.62 5.65 1.48 8.51 12.30 23.67 9.42 1.63 10.40 13.52 29.30 Specific EC (µs/cm) 402 451 444 501 379 386 599 726 707 659 617

Dissolved O2 (mg/L) 9.43 9.99 15.06 8.74 9.47 12.43 10.12 10.69 10.11 9.74 16.4

Isotopic Values (‰) 34 δ SSO4 5.5 4.9 7.5 3.9 0.5 5.0 0.5 -0.3 -0.0 2.2 0.3 18 δ OSO4 1.4 1.6 1.4 0.6 0.9 0.1 -0.7 2.0 -0.3 0.4 -0.2 2 δ HH2O -110 -109 -108 -106 -113 -108 -119 -101 -117 -112 -112 18 δ OH2O -11.9 -12.1 -11.9 -10.8 -12.1 -12.0 -13.9 -10.6 -12.7 -13.0 -12.9 15 δ NNO3 5.1 -0.5 6.5 4.6 15.6 - -0.2 6.3 - 18 δ ONO3 28.8 12.0 28.8 16.8 24.6 - 6.5 14.7 - 13 δ CHCO3 6.3 -4.6 3.3 -2.0 -6.9 -10.2 -2.3 -4.5 -3.0 -1.6 -1.8 181

182

III: WASTEWATER TREATMENT PLANTS AND SHORT-TERM SAMPLING SITES IN THE BOW RIVER IN CALGARY

Location: TPBB (231 km) TPFC (245 km) T1 T2 T3 U1 U2 U3 Constituents 4-Apr-08 10-May-08 22-Jul-08 4-Apr-08 10-May-08 23-Jul-08 Ion Concentrations (mg/L) Ca 59.6 61.6 59.9 76.1 75.7 76.0 Mg 20.8 23.7 28.1 28.5 34.8 40.4 Na 75.5 84.1 81.5 122.7 118.9 114.0 K 17.94 19.28 15.95 15.44 15.74 13.62

NH4 0.302 0.407 0.244 30.370 28.746 28.710

HCO3 141 141 175 333 319 364

SO4 124.1 147.7 172.7 198.7 244.4 244.1 Cl 98.25 83.8 77.2 119.71 96.9 92.3

NO3 48.81 56.72 65.53 0.30 0.06 0.38 TDS 586 618 676 925 934 974

Field Measurements pH 7.09 6.82 7.28 6.63 6.55 6.67 Temperature (oC) 12.70 13.83 17.81 12.50 12.62 17.01 Specific EC (µs/cm) 859 923 931 1341 1365 1378

Dissolved O2 (mg/L) 6.25 6.11 6.14 6.73 3.88 6.39 Isotopic Values (‰) 34 δ SSO4 4.7 2.7 -0.5 5.4 1.5 -1.7 18 δ OSO4 0.6 -1.4 -2.2 1.2 -1.8 -3.9 2 δ HH2O -145 -144 -144 -145 -142 -142 18 δ OH2O -18.5 -18.2 -19.2 -18.5 -18.2 -18.6 15 δ NNO3 7.7 8.3 7.7 10.2 12.7 9.2 18 δ ONO3 -9.6 -9.5 -9.7 1.8 8.4 -0.0 13 δ CHCO3 -10.7 -10.7 -12.4 -15.0 -14.9 -16.2 15 δ NNH4 - 21.8 13.2 8.3 9.1 8.0 183

Location: Wastewater Plume at 248 km (FC) V1 V2 V3 V4 V5 V6 V7 V8 B9 V10 Constituents 20-Jun-07 17-Jul-07 30-Aug-07 29-Sep-07 25-Oct-07 29-Nov-07 2-Apr-08 8-May-08 12-Jun-08 22-Jul-08 Ion Concentrations (mg/L) Ca 46.0 40.7 46.2 48.3 48.4 56.1 50.9 44.2 42.7 43.3 Mg 15.0 13.9 16.2 16.8 16.9 18.5 16.5 13.9 13.6 15.0 Na 11.2 8.1 13.3 13.3 22.5 17.7 19.7 25.5 11.3 10.6 K 1.7 1.2 2.1 2.0 2.8 2.6 3.0 2.9 2.5 1.8

NH4 0.206 0.333 0.012 0.582 0.959 1.801 1.842 1.084 0 0.655

HCO3 169 155 155 165 164 188 152 162 173 159

SO4 36.0 36.8 50.9 52.9 58.9 70.1 68.7 44.6 29.3 44.0 Cl 6.1 5.5 9.4 9.4 21.0 14.2 19.9 27.5 5.7 7.7

NO3 1.56 1.72 3.54 4.30 3.76 4.37 5.84 3.36 1.43 0.68 TDS 287 264 297 312 339 373 339 325 279 282

Field Measurements pH 8.00 7.50 7.20 7.55 7.50 7.88 7.95 7.59 8.16 8.44 Temperature (oC) 13.50 17.35 14.21 9.18 6.34 0.29 5.04 6.57 9.73 17.56 Specific EC (µs/cm) 358 327 293 407 463 484 472 453 346 369

Dissolved O2 (mg/L) n/a 9.89 9.41 9.46 9.70 13.11 16.15 9.45 10.21 9.41

Isotopic Values (‰) 34 δ SSO4 4.2 6.4 6.1 9.3 6.7 8.2 8.5 6.8 -0.1 6.6 18 δ OSO4 -0.8 -1.5 -0.7 -0.6 0.2 -0.4 1.3 -0.7 -0.5 -1.8 2 δ HH2O -18.3 -19.2 -19.0 -18.6 -18.7 -18.9 -18.9 -18.7 -18.8 -19.4 18 δ OH2O -143.5 -151.0 -145.2 -144.0 -143.8 -147.3 -144.6 -145.3 -142.3 -150.6 15 δ NNO3 6.7 8.8 8.5 8.4 7.7 7.8 8.7 7.6 7.9 7.9 18 δ ONO3 -7.6 -7.3 -8.8 -8.8 -9.2 -8.1 -8.2 -2.7 -5.8 -8.9 13 δ CHCO3 -9.6 -7.5 -9.6 -8.5 -9.5 -8.5 -7.1 -9.3 -10.4 -8.7 15 δ NNH4 8.6 5.5 10.1 9.9 9.1 9.6 1.1 8.0

184

EC δ 34S_ δ 18O_ δ 13C_ δ 18O_ δ 2H_ δ 15N_ δ 18O_ Stn. Sample Dist. Temp DO (µs/ HCO3 SO4 Cl NO3 Ca Mg Na K NH4 SO4 SO4 DIC water water NO3 NO3 Code ID (km) Date (oC) pH (mg/L) cm) (mg/L) (mg/L) (mg/L) (mg/L) (mg/L) (mg/L) (mg/L) (mg/L) (mg/L) (‰) (‰) (‰) (‰) (‰) (‰) (‰) W0 OD0804 230 4/2/08 1.14 7.02 13.6 349 154 49.1 3.0 0.55 48.8 14.5 4.1 0.6 0.057 11.3 1.4 -5.9 -19.3 -147 7.3 1.3 W1 BB0804 231 4/2/08 12.01 6.95 7.3 838 138 120.3 98.9 64.38 59.1 20.4 75.8 18.2 0.287 5.0 0.9 -12.0 -19.2 -144 8.2 -10.0 W2 HT0804 234 4/2/08 5.16 7.41 12.9 484 148 72.7 21.1 17.26 51.5 16.1 23.3 5.3 0.064 8.0 1.2 -7.1 -19.1 -145 8.3 -9.4 W3 DW0804 236 4/2/08 4.88 7.92 13.7 435 151 64.2 14.1 10.86 50.4 15.6 16.2 3.5 0.059 9.0 1.3 -6.3 -19.2 -145 8.4 -9.7 W4 BS0804 244 4/2/08 4.71 8.51 15.1 397 150 59.7 10.6 6.91 48.3 15.2 12.4 2.5 0.043 9.4 1.9 -5.5 -19.1 -145 9.0 -7.5 W0 OD0805 230 5/8/08 7.19 8.46 10.9 354 155 44.5 6.3 0.32 46.7 13.8 6.5 0.8 0.035 11.3 1.8 -6.2 -18.6 -147 6.0 4.7 W1 BB0805 231 5/8/08 13.65 7.18 6.6 930 146 161.0 81.0 20.33 61.5 23.6 83.6 19.2 0.375 2.4 -1.3 -11.2 -18.5 -146 8.0 -9.9 W2 HT0805 234 5/8/08 8.70 7.61 10.4 519 155 73.8 26.2 19.56 50.8 16.3 28.7 5.9 0.115 8.5 0.9 -7.7 -19.0 -145 8.0 -10.2 W3 DW0805 236 5/8/08 7.49 7.82 10.1 460 151 65.4 19.1 4.88 48.9 15.2 20.0 3.6 0.018 7.1 0.3 -7.2 -18.7 -146 8.5 -8.8 W4 BS0805 244 5/8/08 7.27 8.35 10.2 380 194 49.0 13.1 1.06 44.7 14.2 14.2 2.0 0.012 10.0 1.2 -7.0 -19.3 -147 8.5 -5.6 W0 OD0806 230 6/13/08 10.44 8.32 10.6 312 148 29.8 3.7 1.08 40.1 12.7 7.1 1.6 0 4.1 0.5 -9.0 -19.2 -147 6.7 0.9 W2 HT0806 234 6/13/08 10.98 7.98 10.6 379 159 41.7 9.6 4.30 43.1 15.1 13.9 2.4 0 1.9 -0.8 -9.3 -18.9 -145 7.4 -9.2 W4 BS0806 244 6/12/08 9.90 8.07 10.3 357 164 37.1 6.4 2.08 42.8 14.4 11.7 2.3 0 1.3 0.2 -9.6 -19.1 -146 7.5 -6.9 W0 OD0807 230 7/22/08 17.22 8.60 9.6 295 141 32.5 1.7 1.11 39.7 12.8 2.7 0.6 0.014 9.5 -1.8 -6.6 -19.9 -152 4.9 3.9 W2 HT0807 234 7/22/08 17.26 8.05 9.0 400 151 51.8 11.8 2.67 42.9 15.3 15.3 3.0 0.022 5.1 -2.6 -8.0 -19.7 -151 8.0 -9.6

185

186

APPENDIX C: SAMPLE CALCULATION FOR CALCITE SOLUBILITY AT 0ΟC AND 1 ATMOSPHERE

187

Basic Thermodynamic Equations:

o o o ∆GR = ∆H R − T∆S R o o T Cp o Q ∆H R − ∆GR S T = S 0 + dT ⇔ ∆S R = = ∫0 T T T o ∆GR = −RT ln K eq

Van’t Hoff’s equation for computing changes in the Keq at different temperatures: d ln K ∆H o = R dT R ∗T 2 o ∆H R ⎡ 1 1 ⎤ ln K 2 − ln K1 = ∗ ⎢ − ⎥ R ⎣T2 T1 ⎦ where R =1.98 cal/degree/mol o o for T1=25 C = 298.14 K

o ⎡219.30 ⎤ log K 2 = log K1 − ∆H R (kcal) ⎢ − 0.7355⎥ ⎣ T2 ⎦ Example Calculation for Calcite Dissolution: : + 2+ - CaCO3 + H → Ca + HCO3 o ∆G f : -269.78 0 -132.18 -140.31 o ∆H f : -288.45 0 -165.18 -129.77

o o : calculate Keq at standard temperature 298.15 K (25 C)

o ∆GR = (-132.18+(-140.31))-(-269.78+0) = -2.71 kcal/mol

o − ∆GR 2.71 ln K = ⇔ log K o = = 1.99 RT 25 C 1.364

o o : calculate Keq at another temperature such as 273.15 K (0 C)

o ∆H R = (-165.18+(-129.77))-(-288.45+0) = -6.5 kcal/mol ⎛ 219.30 ⎞ log K o = 1.99 + 6.5⎜ − 0.7355⎟ = 2.43 0 C ⎝ 273.15 ⎠ Values of enthalpy and free Energy of formation of species at standard temperature (25oC) and pressure (1 atmosphere) are from Weast (1989).

188

APPENDIX D: ESTIMATED CONTRIBUTIONS TO THE TOTAL DISSOLVED SOLID CONCENTRATIONS IN THE BOW RIVER FROM DIFFERENT DISSOLVED CONSTITUENTS AND WATER TYPES

TDS Ca(1-2x)Na2xSO4 CayMg(1-y)CO3

Location Na-Cl 2Na-SO4 Ca-SO4 Ca-Mg-2CO3 Ca-CO3 CO2 (aq) (mmol/L) SO4-type HCO3-type

LL - 0 km 0.01 ± 0.002 0.01 ± 0.004 0.13 ± 0.01 0.36 ± 0.02 0.05 ± 0.02 0.72 ± 0.07 2.58 0.14 ± 0.01 0.78 ± 0.05 0.6 % 0.9 % 10.0 % 56.2 % 4.2 % 28.0 % 100% 10.6 % 60.4 %

CM - 99 km 0.03 ± 0.01 0.02 ± 0.004 0.38 ± 0.11 0.52 ± 0.06 0.09 ± 0.03 1.00 ± 0.11 4.12 0.40 ± 0.11 1.13 ± 0.10 1.4 % 1.1 % 18.6 % 50.2 % 4.6 % 24.1 % 100% 19.3 % 54.8 %

CC - 179 km 0.04 ± 0.01 0.03 ± 0.01 0.35 ± 0.08 0.55 ± 0.06 0.18 ± 0.03 1.12 ± 0.09 4.57 0.38 ± 0.09 1.28 ± 0.10 1.9 % 2.0 % 15.5 % 48.2 % 7.8 % 24.6 % 100% 16.8 % 56.0 %

BN - 212 km 0.06 ± 0.02 0.04 ± 0.01 0.35 ± 0.10 0.56 ± 0.05 0.20 ± 0.05 1.14 ± 0.08 4.69 0.39 ± 0.11 1.32 ± 0.10 (Calgary) 2.4 % 2.4 % 15.0 % 47.7 % 8.3 % 24.2 % 100% 16.6 % 56.0 %

CL - 302 km 0.24 ± 0.17 0.13 ± 0.03 0.39 ± 0.12 0.63 ± 0.06 0.16 ± 0.07 1.19 ± 0.10 5.72 0.52 ± 0.14 1.43 ± 0.10 8.5 % 6.9 % 13.7 % 44.4 % 5.6 % 20.9 % 100% 18.3 % 50.0 %

CN - 378 km 0.22 ± 0.10 0.19 ± 0.07 0.39 ± 0.11 0.65 ± 0.06 0.12 ± 0.08 1.23 ± 0.15 5.90 0.59 ± 0.18 1.43 ± 0.10 7.5 % 9.9 % 13.3 % 44.3 % 4.2 % 20.8 % 100% 19.9 % 48.5 %

BC - 482 km 0.23 ± 0.115 0.25 ± 0.14 0.40 ± 0.11 0.67 ± 0.10 0.08 ± 0.08 1.21 ± 0.18 6.05 0.65 ± 0.25 1.41 ± 0.18 7.6 % 12.4 % 13.4 % 44.0 % 2.6 % 20.0 % 100% 21.7 % 46.6 %

SD - 513 km 0.23 ± 0.12 0.26 ± 0.14 0.44 ± 0.15 0.70 ± 0.16 0.04 ± 0.08 1.24 ± 0.28 6.24 0.70 ± 0.29 1.44 ± 0.31 7.3 % 12.5 % 14.3 % 44.8 % 1.2 % 19.9 % 100% 22.6 % 46.0 %

RL - 571 km 0.22 ± 0.09 0.26 ± 0.13 0.43 ± 0.14 0.69 ± 0.10 0 ± 0 1.19 ± 0.20 5.99 0.68 ± 0.27 1.37 ± 0.18 7.3 % 12.9 % 14.3 % 46.1 % 0 % 19.9 % 100% 22.6 % 45.7 % 189

190

APPENDIX E: SOURCES OF ARC-GIS BASEMAP FILES AND LIST OF SOFTWARES

191

Sources of ARC-GIS Basemap Files:

Maps, Academic, Geographic Information Centre (University of Calgary) http://library.ucalgary.ca/madgic

ArcCanada version 3 (CD-ROM)

Alberta Geological Survey http://www.ags.gov.ab.ca/gis/download_gis.htm

Agriculture and Agri-Food Canada – Prairie Farm Rehabilitation Administration http://www4.agr.gc.ca/AAFC-AAC/display-afficher.do?id=1228406865942&lang=eng

ESRI Data and Maps http://www.esri.com/data/data-maps/index.html

Softwares:

OriginPro 8.1 ARC-GIS: ArcMap 9.2 AquaChem 51 Adobe Acrobat Professional 6.0 Adobe Photoshop CS5 Adobe Illustrator CS5 Microsoft Office Microsoft Excel