Implementation of IWRM has generally been approached mechanistically, with attention focused on identifying necessary conditions and developing useful tools and techniques. In contrast, this article examines alternative approaches to implementation in their totality, using IWRM in England as a case analysis. In England, the EU Water Framework Directive has been implemented through a ‘top-down’ approach but a ‘bottom-up’ approach has been adopted for catchment management. Both the Water Framework Directive and the catchment-based approach are consistent with the goals of IWRM, but their implementation arrangements are disconnected and operate at different scales. This example suggests that cross-scale interplay and bridging institutions are critical to the successful implementation of IWRM in complex governance settings.