In the Netherlands, a country of water, dikes, and dams, the role of civil engineering in policy making and public debates over flood safety have changed over the last four decades. This had not just implied that new directions in flood safety policy were considered by politics, but also that engineering experts traditionally working in this area found their credibility challenged by competing expertises. I will argue that in responding to those challenges, experts combined boundary work (upholding boundaries between science and non-science, or between different fields of expertise) with identity work, in which the planning of actions and learning from experience are informed by the identity of oneself as an expert. The views of experts on the boundary zone of science, policy, and public debate, and the role and skills one attributes to oneself, are regarded as important aspects of that identity work. On the basis of biographical-narrative research, this will show that although the four experts studied here belong to a specific generation of engineers, experiencing common challenges and developments in their field of work, the combination of identity work and boundary work results in specific roles and responses for each individual expert.