This study aims at advancing collaborative governance theory by investigating the interaction between two different collaborative arrangements within the same forested area of high ecological and social value in the Vindel River basin. Semi-structured interviews, policy documents and observations of board meetings were analysed based on analytical typologies of collaborative arrangements to answer the following questions: which factors can explain why a new collaborative arrangement was established within an area where one already existed? In what way do the two arrangements compete with or complement each other? And, to what extent do they address the effects of forestry on water? The analysis shows that a new collaborative arrangement was formed because the existing arrangement did not materialise certain stakeholders' expectations. Moreover, the two collaborative arrangements do not compete but rather complement each other. The newly established organisational/action collaborative arrangement presented those stakeholders most interested in on-the-ground action with the appropriate venue while freeing them from the organisational/policy arrangement that did not match their aims. However, both arrangements experienced power misbalances as certain stakeholders were perceived as having more influence on their agenda. Collaboration at this local-regional level was found to focus on limited problems with concrete and feasible solutions, such as fish migration, rather than on the complex problems with solutions marked by ecological uncertainty and power asymmetries, e.g. diffuse pollution from forestry.