Relaxing the Principle of Prior Appropriation: Stored Water and Sharing the Shortage in Alberta, Canada

Abstract

Prior appropriation (allocation), ‘first-in-time is first-in-right’, provides a dominant water policy in western North America and some other regions world-wide. Concerns with this chronological prioritization arose during the Canadian Oldman River Dam project, since anticipated water for environmental flows and an indigenous group would have been unreliable with junior licenses. It was considered that in Alberta prior allocation applies only to the natural flow and water captured in a reservoir during surplus is not later bound by license seniority. Consequently, the Oldman Dam operation ensures minimal environmental flows and thereafter, ‘sharing the shortage’ is applied, with licensees receiving partial allotments during shortages. A related test-case for adjacent rivers with publicly-funded reservoirs accompanied a water shortage in 2001. It was considered unacceptable to cut-off water to a food-processing plant, a town, and water co-operatives with recent licenses, and consequently irrigation districts and others agreed to share the shortage, with all receiving 60% allotments. Following success, water sharing was also approved for 2002 and 2007. The discretionary use of stored water and sharing the shortage represent ‘equitable allocation’, an alternative to prior appropriation, which may benefit other jurisdictions facing water shortages.