Environmental conflict management involves the management of multiple stakeholders with conflicting stakes. In this paper, an attempt is made to develop a shared mental model of stakeholders in an environmental conflict. The Transmission Gully project, a large-scale transport infrastructure project in the Wellington region of New Zealand is used as a case study. Selected stakeholders of this project tried to generate this shared model, in the form of a causal loop diagram. This model is analysed qualitatively to provide different insights into potential system behaviours.