Assessing stakeholder impacts and adaptation to low water-levels: the Trent-Severn waterway

The Trent-Severn Waterway in central Ontario, Canada, is a large inland water system. It is managed for a broad range of stakeholders with different needs and expectations, creating a complex management context. Although variations in water levels occur, extreme low water-level events may increase in the future due to climate change, challenging management practices, in addition to requiring adaptation to reduce impacts. A modified policy Delphi was used to generate and evaluate ideas related to historical and future water-level impacts and adaptations. The paper presents the perspectives of three groups—cottagers and homeowners (CH), government (G), and industry and business (IB)—on their experiences with historic low water-levels, as well as their perspectives on future impacts and adaptations using two water-level scenarios: a moderate decrease of 25 cm and a more severe 50 cm decline. Shared impacts and adaptations (individual and collective) were identified along with those that were unique to a group. The likelihood of and consensus on potential impacts and most adaptations increased with the severity of water-level reduction. All groups indicated a higher likelihood of using collective rather than individual adaptations with the severe scenario, and in some cases, their contacts for assistance with adaptation broadened. While the modified policy Delphi requires significant effort by the analyst and respondents, it provides a useful framework for generating and analyzing perceptions and preferences of diverse stakeholders.