Assessment of blue water-green water interchange under extreme warm and dry events across different ecohydrological regions of western Canada

•BW and GW are interlinked through dissimilar physical processes across ecoregions.•GW-BW relationship and their shift were projected under extreme warm and dry events.•In Mountains, future BW declines while GW maintains due to legacy moisture.•In natural lands, BW to GW shift is projected with a lag time and legacy moisture.•In crop lands, remarkable shortages in BW are projected with no shift to GW.