As part of the National Energy Board (NEB) review process of the Trans Mountain Expansion Project (TMEP), Matsqui First Nation commissioned EcoPlan to conduct a socio-cultural impact assessment of the proposed pipeline that would pass through their traditional territory. Our approach to this impact assessment and the techniques employed had to address several challenges posed by the project, including: identifying a broad range of socio- cultural impacts (less tangible values that conventional impact assessments often fail to incorporate; identifying impacts from a future event (as the pipeline was not yet built, various future scenarios had to be developed, translating the technical language of assessment reports into meaningful narratives of events that may unfold); translating the impacts into a language regulators could understand (providing a clear, quantitative expression of how the project would affect Matsqui’s way of life and ability to thrive as a rights-bearing people). Our report addressed critical gaps regarding the biophysical, social, cultural and economic impacts of the Trans Mountain Facilities Application to the NEB. It also brought together analysis of well-established scholarship and regulatory precedent to extend the purview of impact assessment beyond the typical market-based approach.