Cumulative effects assessments at Hydro-Québec: what have we learned?

Abstract

Listen

Translate article

Twelve cumulative effects assessments (CEAs) have been conducted at Hydro-Québec since 1999. This article explains how they have evolved in a seven-step approach. It also describes the problems encountered and solutions found for each of these steps. Hydro-Québec's CEAs focus on historical and regional perspectives, including a detailed past baseline description. However, there is no specific methodology proposed for significance determination, and possibly no need for it. CEAs provide a broader view that is found useful to assess impacts sometimes not properly tackled at the project level, but the question of how the promoter should conduct follow-up and mitigation efforts in the context of cumulative effects is still open. CEA must be a separate section of an impact assessment with its own methodology, spatial and temporal scales. Only certain environmental components should be examined. A well-documented past baseline condition is essential. Future effects can rarely be predicted over a ten-year period when combined with other impact sources. Cumulative effects with other future projects are difficult to determine when no direct impact can be found at the project level.