Trend analysis of water quality in the irrigation districts of southern Alberta, Canada

Abstract

Irrigation is essential for high agricultural production and crop diversity in semi-arid regions such as southern Alberta, Canada. Nearly 75% of Canada's irrigation takes place in Alberta's irrigation districts, making the management and maintenance of irrigation water quality highly important in this region. In this study, temporal water quality trend analysis was conducted on southern Alberta irrigation water from 2006 to 2023. The trends of 19 water quality parameters, including nutrients, salinity, physical characteristics, Escherichia coli, and pesticides, were evaluated at 74 sites. Of the total number of parameter-by-site tests (902) conducted, 36.5% had statistically significant decreasing trends, 1.3% had statistically significant increasing trends, and 62.2% had no trend. This indicates stability and improvement in water quality during the study period at the resolution of individual sites. Regional trend analysis revealed trends in 11 out of the 19 parameters tested: 9 decreased, 2 increased, and 8 exhibited no trend, which also indicated stable and improving water quality. Continued monitoring is important for areas and parameters showing increasing trends to guide mitigation action. This information can be used to focus water and land management decisions and direct resources to priority areas and parameters to ensure excellent quality irrigation water for all users.