Streamflow Is Changing in Rivers Across Alberta: Assessing Regional Variation in Changing Hydrologic Indices
Total Page:16
File Type:pdf, Size:1020Kb
Streamflow is changing in rivers across Alberta: assessing regional variation in changing hydrologic indices by William Kyle Hamilton A thesis submitted in partial fulfillment of the requirements for the degree of Master of Science in Wildlife Ecology and Management Department of Renewable Resources University of Alberta © William Kyle Hamilton, 2020 Abstract The flow regime is a crucial factor in the well-being of aquatic and riparian ecosystems. Many components of those ecosystems, ranging for nutrient transport to morphology, are impacted by various hydrologic parameters. The parameters help define and quantify five important hydrologic regime characteristics: magnitude, duration, timing, frequency, and rate of change. Our study utilized the Indicators of Hydrologic Alteration (IHA) indices to (1) determine how various ecologically relevant components of streamflow are changing across Alberta’s various natural regions; and (2) examine the similarities and differences between streamflow trends and climate trends. The overarching goal of these objectives is to create a foundation upon which water management practices can be created or modified. Region-specific water management is required to balance the residential, commercial, and industrial water needs of a particular region with ecological concerns and conservation initiatives. Understanding the trends in hydrologic parameters is an important step in recognizing the vulnerabilities of each region. Streamflow at Water Survey of Canada stations was assessed for linear trends using a Mann-Kendall Trend Analysis. Our approach of assessing overall trends on a regional basis was validated when looking at trends in magnitude. The average daily flow rate for spring and summer months was found to be decreasing in the Boreal Natural Region but increasing in the Grassland Natural Region. Other hydrologic indices were found to exhibit significant trends on a province-wide level. Annual minimum and maximum flow conditions over a variety of durations were observed to be merging across the province. Similarly, the rate of change of streamflow between consecutive days is decreasing across Alberta. ii To determine whether these results were the function of climate oscillation patterns, a composite analysis was performed to determine the effect of the El Niño–Southern Oscillation (ENSO) and Pacific Decadal Oscillation (PDO) on hydrologic indices. Only 8% of parameters were found to be significantly influenced by PDO patterns and 4% influenced by ENSO patterns. iii Preface This thesis is an original work by W. Kyle Hamilton. No parts of this thesis have been previously published. iv Acknowledgements The completion of this dissertation would not be possible without the guidance and support of many individuals. This project would not have been possible without the technical support, mentorship, and patience of Dr. Mark Poesch. I would also like to thank the other members of the Fisheries & Aquatic Conservation Lab for their continued technical assistance, encouragement, and friendship over the years. Many thanks to Dr. Axel Anderson and Dr. David Olefeldt for sitting on the examination committee. I would like to thank my family for their encouragement throughout the project and Koda and Cooper for keeping me company during late nights in the office. Most importantly, I would like to acknowledge the support of my wife, Ali McNaught. Many of our life milestones have come and gone while I have been completing this dissertation, and I cannot overstate how much I appreciate her patience and reassurance. This work would not have been possible without her, and for that, I will be forever grateful. v Table of Contents Table of Contents ............................................................................................ vi List of Tables ................................................................................................ viii List of Figures ................................................................................................. xi 1 Introduction .............................................................................................. 1 2 Methods .................................................................................................. 10 2.1. Study Area ........................................................................................ 10 2.2. Hydrological variables ......................................................................... 11 2.3. Climate variables ............................................................................... 11 2.4. Trend analysis ................................................................................... 11 2.5. The Influence of Climate Oscillation Patterns ......................................... 14 2.6. Comparison of Reference Hydrometric Basin Network ............................. 14 3 Results ................................................................................................... 15 3.1. Mann Kendall Trend Analysis Results .................................................... 15 3.1.1. Monthly Median Streamflow (Group 1) ............................................ 15 3.1.2. Magnitude and Duration of Annual Extreme Conditions (Group 2) ...... 16 3.1.3. Timing of Annual Extreme Conditions (Group 3) .............................. 16 3.1.4. Frequency and Duration of High and Low Pulses (Group 4)................ 17 3.1.5. Rate and Frequency of Change in Water Conditions (Group 5) ........... 17 3.1.6. Climate Parameters ...................................................................... 17 3.2. Detecting the Impact of the Climate Oscillation Patterns ......................... 18 3.3. Trends Observed at Regional Hydrometric Basin Network Stations ........... 18 4 Discussion ............................................................................................... 19 4.1. Climate ............................................................................................. 19 4.2. Overall Trends in Alberta and the Potential Impacts on Fish Communities . 20 4.2.1. Group 1 – Monthly Magnitudes ...................................................... 21 4.2.2. Group 2 – Annual Extreme Condition Variables ................................ 22 4.2.3. Group 5 – Rate and Frequency of Change Variables ......................... 22 4.3. Regional Results ................................................................................ 23 4.3.1. Boreal Region .............................................................................. 23 4.3.2. Grassland Region ......................................................................... 26 4.3.3. Parkland Natural Region ............................................................... 28 4.3.4. Rocky Mountain Natural Region ..................................................... 29 4.3.5. Foothills Natural Region ................................................................ 30 vi 4.3.6. Canadian Shield Natural Region ..................................................... 31 5 Conclusion .............................................................................................. 31 Tables ........................................................................................................... 33 Figures ......................................................................................................... 59 References .................................................................................................... 77 Appendices .................................................................................................... 88 Appendix A – List of Water Survey of Canada (WSC) hydrometric stations in Alberta ...................................................................................................... 88 Appendix B – Mann-Kendal Test Results using the Yue Procedure .................... 133 Appendix C – Spatial Visualization of Mann-Kendal Test Results ...................... 163 vii List of Tables Table 1: Number of stations available for streamflow trend analysis. Table 2: Hydrologic parameters analyzed with the Indicators of Hydrologic Alteration methodology. Table 3: An example of a conceptual ecological model presented in Mathews & Richter (2007), showing the effects of each of the five hydrologic characteristics on successful spawning. Table 4: Climate variables analyzed for trends. Table 5: Trends in monthly flow magnitudes. Table 6: Trends in annual extreme flow conditions. Table 7: Average proportion of stations showing significant trends across all extreme flow condition variables. Table 8: Trends in timing of annual extreme streamflow conditions. Table 9: Regional results for timing of annual extreme streamflow condition parameters. Table 10: Regional results for frequency of high pulse events. Table 11: Trends in streamflow rate and change frequency parameters. Table 12: Trends in seasonal climate variables. Table 13: To determine the impact of climate oscillation patterns on the dataset, a composite analysis was run on each station for each IHA variable. A significant composite analysis result indicates a significant difference between two subsets of data. A significant difference between years with high and low PDO values indicates the data is significantly impacted by the PDO pattern. The percentage of stations where particular IHA parameters are impacted by PDO are summarized by region and across the province. viii Table 14: To determine the impact of climate oscillation patterns on the dataset, a composite analysis was run