Streamflow is changing in rivers across Alberta: assessing regional variation in changing hydrologic indices

• Author / Creator

  Hamilton, William Kyle

• 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.

  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.

• Subjects / Keywords

  • Alberta Natural Regions
  • Indicators of Hydrologic Alteration
  • Mann Kendall Trend Analysis

• Graduation date

  Fall 2020

• Type of Item

  Thesis

• Degree

  Master of Science

• DOI

  https://doi.org/10.7939/r3-acvv-rh06

• License

  Permission is hereby granted to the University of Alberta Libraries to reproduce single copies of this thesis and to lend or sell such copies for private, scholarly or scientific research purposes only. Where the thesis is converted to, or otherwise made available in digital form, the University of Alberta will advise potential users of the thesis of these terms. The author reserves all other publication and other rights in association with the copyright in the thesis and, except as herein before provided, neither the thesis nor any substantial portion thereof may be printed or otherwise reproduced in any material form whatsoever without the author's prior written permission.