Assessing Hydrologic and Policy Implications of Irrigation on the Canadian Prairies Under Climate Change

• Main Author: Vonderbank, Lucas
• Other Authors: Stadnyk, Tricia, Black, Kerry, Pietroniro, Alain, He, Jianxun (Jennifer)
• Format: Master Thesis
• Language: English
• Published: Schulich School of Engineering 2023
• Subjects: climate change; irrigation; Saskatchewan River Basin; hydrologic modelling; Agriculture; Hydrology; Engineering; Engineering > Environmental; First Nations
• Online Access: http://hdl.handle.net/1880/115878; https://doi.org/10.11575/PRISM/40766

The Saskatchewan River Basin (SRB) covers a large portion of the Canadian Prairies. Agriculture represents a dominant land-use in the SRB, and since the early 1900s irrigation has evolved to become an important part of the sector, improving yields and enabling the production of high-value crops. With climate change projected to increase temperatures and alter precipitation patterns, uncertainty surrounding water security for irrigators and First Nations in the SRB is expected to increase. Given the impacts of climate change, the recent announcements from the Alberta and Saskatchewan Governments regarding irrigation expansion, and the risks faced by First Nations under changing streamflow conditions, a hydrologic analysis of the SRB that dynamically incorporates climate change and irrigation is required to assess future water security and the viability of current water governance (i.e., the Master Agreement on Apportionment). This study integrates Prairie-specific irrigation in the HYPE hydrologic model, and uses RCP8.5 NA-CORDEX climate simulations from 1976 to 2070 to estimate the effects of climate change. The results indicate that (1) drier summers are likely to put a strain on irrigation water supplies during the growing season; (2) that irrigation in the upstream reaches of the basin may cause reduced streamflow and a loss of seasonality in the downstream reaches, with implications for riparian ecosystems and the Saskatchewan River Delta; (3) that the system of prior allocation in Alberta puts disproportional water security risk on First Nations under low flow conditions; and (4) that compliance with the Master Agreement on Apportionment may become increasingly challenging on the South Saskatchewan River under future conditions.