Julie Thompson Klein's contributions to interdisciplinary and transdisciplinary research have enriched the way collaboration is discussed and handled by introducing concepts of boundary work and boundary crossing from the field of Science and Technology Studies. In recent years, she has been integrating those concepts into crossdisciplinarity, an effort culminating in the development of a framework for a forthcoming book ("Beyond Interdisciplinarity: Boundary Work, Collaboration, and Communication in the 21st Century"). With her permission, we have used an earlier version of her framework to analyze boundary work and boundary crossing in transdisciplinary sustainable water management projects in Australia and Switzerland. The aim of using the framework has been twofold: to explore and assess the heuristic value of the framework, i.e. how it improves our conceptualization of boundary work in the two projects, and to examine the framework itself, i.e. whether some of the seven concepts involved are hard to work with or should be further developed.