Using Comparative Social Impact Assessment to Understand Resistance and Support for Causeway Removal and Tidal River Restoration

Abstract

Since the mid-20th century, the adverse impacts of barriers in rivers, such as dams and causeways, have been widely acknowledged. Barrier infrastructure requires reexamination considering modern values and technology that allow, or require, more environmentally sound approaches for development. Barrier removal is often locally contested, yet few studies focus on understanding local people’s experiences in dammed river landscapes. The research included in this dissertation is intended to address this gap. We conducted a mixed-methods comparative social impact assessment to explore the evolution of two dammed tidal river landscapes and local people’s responses to landscape changes over time.

Our study sites are the Petitcodiac River, where a causeway was partially removed and natural tidal flow was re-established, and the Avon River, where causeway modifications are under consideration. Both sites are located on the inner Bay of Fundy on Canada’s East Coast. The objectives of this research were to: 1) look backward to assess how residents’ connections to and uses of a restricted tidal river and estuary developed over time with landscape change and infrastructure development; 2) determine how present uses, experiences, and perceptions of landscape change influence support for restoring tidal connectivity; and, 3) look forward by assessing cognitive and affective social impacts from Petitcodiac River causeway modifications to provide insights about the similar case evolving in the Avon River context.

There are three major findings from this work corresponding with each of the research objectives: 1) landscape values in times of transition require an understanding of the past and expectations for the future, as well as present uses and preferences; 2) social indicators of support for restoring tidal connection are measurable for ongoing, contentious decisions and strongest among them are landscape perceptions; and 3) comparative social impact assessment is an effective way to understand experienced social impacts and social acceptance over time during management changes. Rather than anticipating impacts, the main advantage of this approach is building understanding about perceptions, concerns, and expectations when modifying river barriers. We can learn from the Avon and Petitcodiac cases and make progress towards improving infrastructure adaptation and river restoration outcomes with benefits for people and the environment.