A dense (and growing) population, the effects of climate change, an existing arid climate in much of the basin, and growing demand among competing users - coupled with the need to ensure sufficient water to protect aquatic and ecosystem health - all place significant pressure on the basin. Further compounding the challenge is the requirement that 50% of the annual natural flow must pass to Saskatchewan, a neighbouring province. In addition, the province evolved its water allocation policies and the associated legislation, culminating in the proclamation of a new Water Act in 1999. Pursuant to the Water Act, the right to divert and use water is granted by a licence or registration under the Water Act.