Work

Streamflow generation, hydroclimatic changes, and flood mechanisms in the Sheep River basin on the eastern slopes of the Canadian Rockies

Year: 2025

Type: article

Abstract: Study region The Sheep River basin on the Canadian Rockies’ Eastern Slopes of the Rocky Mountains, whose upper basins are unregulated and undeveloped. Study focus We investigated streamflow generation, hydroclimatic changes, and flood-generating mechanisms using parsimonious statistical methods and over 50 years of hydroclimate data at multiple spatial (sub-basin and entire basin) and temporal (annual, seasonal, monthly, and daily) scales. New hydrological insights for the region The upper mountainous basin generated ∼95 % of open-water streamflow, with ∼66 % from the upper-south basin, where rain, snowmelt, and the streamflow coefficient were higher. Annual and open-water precipitation declined in the lower basin, but overwinter precipitation slightly increased basin-wide. Overwinter snowpack loss increased in the lower basin, and snowpack loss seasonality weakened. Air temperature increased across all basins. Despite these climatic changes, streamflow remained unchanged, likely due to groundwater’s buffering effect. Open-water streamflow was primarily driven by rainfall, with additional rapid and slow snowmelt contributions. Overwinter streamflow was predominantly sustained by groundwater, but early snowmelt also contributed. Finally, extreme floods were triggered by heavy precipitation, although high antecedent basin wetness conditions influenced all floods. These findings highlight (i) the importance of mountainous basins in streamflow generation, (ii) the key role of groundwater on streamflow, and (iii) the need to consider complex and diverse hydrologic processes for water supply and flood management in the Sheep River basin under climate change.

Source: Journal of Hydrology Regional Studies

DOI: 10.1016/j.ejrh.2025.102562