Does participatory governance benefit the environment? The European Water Framework Directive (WFD), which came into force in 2000 with the aim of revolutionizing European water governance, mandates participatory river basin management planning across the European Union. The belief of European policymakers and the European Commission is that participation will deliver better policy outputs and implementation. This book examines a range of approaches to participatory river basin management planning, and considers whether and how participation impacted on the environmental standard of planning documents, quality of implementation, and social outcomes. It draws on evidence from WFD implementation in eight case studies from Germany, Spain and the United Kingdom on the basis of a matched comparative case study design. The Directive sets common timeframes and procedural requirements, which provides a perfect test-bed and unique opportunity to study the effects of participation on implementation and outcomes in comparative perspective.