Assessment of Meteorological and Agricultural Drought Indices under Climate Change Scenarios in the South Saskatchewan River Basin, Canada

Climate change has amplified the severity of droughts with potentially adverse impacts on agriculture in western Canada. This study assessed meteorological and agricultural drought Southern Saskatchewan River Basin (SSRB) using an array indices, including Standardized Precipitation Index (SPI), Precipitation-Evapotranspiration (SPEI), Self-Calibrated Palmer Drought Severity (scPDSI), Soil Moisture Deficit (SMDI), Evapotranspiration (ETDI). These indices were evaluated multiple regional climate model (RCM) projections assuming 1.5, 2.0, 3.0 °C thresholds global warming. A modified Water Assessment Tool (SWAT-M) was used to simulate soil water content (SWC), actual evapotranspiration (AET), potential evapotranspiration. The results a sensitivity analysis SUFI-2 method SWAT-CUP showed that performed well BIAS lower than 10% NSE R higher 0.7, range SWC output closely matched observed SWC. According RCM projections, annual precipitation increases for all three temperature while mean at greater rate rise temperature. projected PDSI SPEI suggest duration will exceed historical values SPI remain largely unchanged. Furthermore, severe conditions (SMDI < 2.0) are more frequent under scenario. ETDI historically 0.58 value is 0.2, 0.1, −0.2 first third scenarios, respectively. Simulated values, spatial maps, heat maps SMDI illustrated Canesm2.CRCM5 projects driest among RCMs. Agricultural which incorporate data, show significant effects indices. increasing dryness impact crop production, particularly scenario (3 °C) SSRB.