Evaluating the Role of Social Capital for the Design of Sustainable River Governance Strategies: The Case of Tagus River

ABSTRACT This study examines the role of social capital in designing and implementing more effective governance strategies to improve the state of the Tagus River's significantly deteriorated middle reach (Spain). We employed social network analysis (SNA) to evaluate the bonding, bridging and linking social capital and the quality of stakeholder relationships. The findings revealed a loosely connected network, with only 8.3% of the possible links, and limited social capital. This hinders collaboration for Tagus River restoration. Media and civil society showed the highest bonding capital (density of 30% and 25.8%, respectively), while media and decision‐makers held bridging roles (average betweenness of 0.1 and 0.064, respectively). Additionally, relationship quality was undermined by conflicts, with 10 stakeholders—seven from civil society and three decision‐makers—identified as the main sources of conflict. These insights are crucial for shaping efficient management strategies and underscore the necessity to prioritise inclusivity, foster relationships and resolve conflicts.