A quantification and analysis of historical sectoral and regional water withdrawals in Canada

Canada is a water rich country with one of the highest annual water uses per person among developed countries. This study provides a systematic, comprehensive analysis of recent data on this water use at national and subnational scales. It spatially disaggregates surveyed data from Statistics Canada (StatCan) to develop a historical dataset from 2005-2018 for Canadian water withdrawals at provincial and river basin scales for seven water use sectors: domestic use, manufacturing, irrigation, livestock, mining, oil and gas and thermal power generation. Additionally, sectoral water withdrawals are estimated for each province-river basin combination. Sectoral priorities are analyzed at the provincial and river basin scales and historical trends are identified. Water use intensity indicators are calculated and compared between different provinces, and a water stress index is used to identify regions most prone to water shortages. We find that water use decreased nationally over the study years for all sectors except irrigation, mining and oil and gas. Ontario had the highest water use of all provinces, mainly for thermal power generation. Manufacturing and domestic sectors were the dominant users in Quebec and British Columbia while the Prairies had more diversified uses. Domestic water use per capita values in Newfoundland & Labrador and Quebec are higher than the national average and all global values included in the study for comparison. Finally, the irrigation sector withdraws the most water per $GDP nationally while the oil and gas sector withdraws the least. Dataset development faced challenges related to data availability and uncertainties in downscaling assumptions. These challenges are described, and emphasize the need for a systematic and standardized approach to water data gathering and sharing in Canada.