The second case study focuses on the Danube River Basin in Central and Eastern Europe, governed by the ICPDR. The Danube River Basin faces very different collective action problems than the Mekong River Basin and is characterized by different interests and constellations of riparian states. It represents a river basin in the developed world, challenged by water quality rather than water quantity problems. This allows for testing our hypotheses in a very different setting, increasing the generalizability of findings. From a social science perspective, research on the Danube River Basin and the ICPDR is very limited. Some authors have focused on the collective action problems in the river basin and the potential conflicts arising from them (Jansky et al., 2004; McCaffrey, 2006), but the ICPDR itself has received limited attention (among the few existing analyses, refer to Linnerooth-Bayer and Murcott, 1996; Schmetje and Weller, 2005). In addition, a number of studies focus on the role of external support to the ICPDR as a means for solving water-related collective action problems (Margesson, 1997; Nachtnebel, 2000; Gerlak, 2004b). Water law scholars have been particularly interested in the Gabcˇikovo-Nagymaros Dam dispute between Hungary and Slovakia (Margesson, 1997; Fuyane and Madai, 2001), but accord little interest to the ICPDR. Research on the ICPDR therefore largely relied on official documents, with document access being facilitated by the RBO’s very open information-sharing policy that makes most documents available on the RBO’s website and its openly accessible database. In addition, interviews with representatives of the ICPDR, its member states as well as external actors (both donors and NGOs) have provided important insights into how the ICPDR governs the Danube River Basin (a list of interviewees is provided in Appendix 5.1).