Assessing climatic drivers of spring mean and annual maximum flows in western Canadian river basins

Date

2021

Authors

Dibike, Yonas B.
Shrestha, Rajesh R.
Johnson, Colin
Bonsal, Barrie
Coulibaly, Paulin

Journal Title

Journal ISSN

Volume Title

Publisher

Water

Abstract

Flows originating from cold and mountainous watersheds are highly dependent on temperature and precipitation patterns, and the resulting snow accumulation and melt conditions, affecting the magnitude and timing of annual peak flows. This study applied a multiple linear regression (MLR) modelling framework to investigate spatial variations and relative importance of hydroclimatic drivers of annual maximum flows (AMF) and mean spring flows (MAMJflow) in 25 river basins across western Canada. The results show that basin average maximum snow water equivalent (SWEmax), April 1st SWE and spring precipitation (MAMJprc) are the most important predictors of both AMF and MAMJflow, with the proportion of explained variance averaging 51.7%, 44.0% and 33.5%, respectively. The MLR models’ abilities to project future changes in AMF and MAMJflow in response to changes to the hydroclimatic controls are also examined using the Canadian Regional Climate Model (CanRCM4) output for RCP 4.5 and RCP8.5 scenarios. The results show considerable spatial variations depending on individual watershed characteristics with projected changes in AMF ranging from −69% to +126% and those of MAMJflow ranging from −48% to +81% by the end of this century. In general, the study demonstrates that the MLR framework is a useful approach for assessing the spatial variation in hydroclimatic controls of annual maximum and mean spring flows in the western Canadian river basins. However, there is a need to exercise caution in applying MLR models for projecting changes in future flows, especially for regulated basins.

Description

We acknowledge WSC, PCIC, NASA and CCCma for all data used in this study.

Keywords

peak flows, multiple linear regression, predictor, predictand, snow water equivalent, annual maximum flow, climate change, western Canada

Citation

Dibike, Y., Shrestha, R. R., Johnson, C. E., Bonsal, B., & Coulibaly, P. (2021). Assessing climatic drivers of spring mean and annual maximum flows in western Canadian river basins. Water, 13(12), 1617. https://doi.org/10.3390/w13121617