Collective action among resource users has long been identified as a basic element of successful common pool governance, and one of the main concerns of common pool research is the identification of factors that affect collective action. Among the most commonly identified factors are trust, social capital, common preferences, shared knowledge, collaborative experiences, focusing events and expectations of future interactions. Thus far, however, relatively little attention has been paid to the historical-institutional context of collective action and the constraining effects of path dependency. Path dependency suggests that investments and adaptations in early resource management institutions can make it difficult for actors to abandon these institutions, thereby influencing and shaping subsequent collective action efforts. This article examines the impact that path dependency can have on collective action in common pools, by examining basinlevel water management in the Murray-Darling Basin of Australia, the Colorado Basin of the US and the Saskatchewan-Nelson Basin of Canada. In all three cases, early water apportionment institutions have proven strongly path dependent, significantly shaping subsequent collective action efforts at water conservation.
